dentistry the italian tribute treatise of implant to ... · treatise of implant dentistry 4) (4)....

Ugo Pasqualini - Marco E. Pasqualini

Forewords by:

Leonard LinkowCesare BrusottiEnrico CislaghiPier Luigi FlorisDino GarbaccioHans GrafelmannAraceli Morales SánchezBenito Vernole

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THE ITALIAN TRIBUTETO MODERN IMPLANTOLOGY

TREATISE OF IMPLANTDENTISTRY

Copertina titolo MA 1-10-2009 11:31 Pagina 3

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Despite the fairly recent rise of oral implantolo-gy from a scientific point of view, it must beremembered that the origins of this discipline

go back to ancient times. There are well-known descriptions of archaeologi-cal findings from the pre-Columbian era exhibitingstone inlays in teeth or even used to replace miss-ing dental elements (1). It is known that the Maya used bow drills (Fig. 1) toperform the “cosmetic” filing of natural teeth on liveindividuals, and tooth shaping varied according toregions and tribes. Malvin E. Ring reports that theywere also skilled at inlaying very well-carved stonesin meticulously prepared cavities on the labial sur-face of the front teeth and sometimes in premolars.These inlays, which served a purely aesthetic pur-pose, were made of a great variety of rounded min-erals of different colors, such as turquoise, quartz,serpentine and cinnabar (Fig. 2) (2).

The cavities were undoubtedly prepared in livingteeth. According to Ring, ancient oral surgeonswould spin a round hard tube similar in shape to adrinking straw, originally made of jade and later ofcopper (Fig. 3), between their hands or using a bowdrill, applying a slurry of powdered quartz in wateras an abrasive to cut a perfectly round hole in theenamel and dentin. The carved stones were then setin these cavities, fitting them so perfectly that manyhave remained in place for thousands of years (2,3). Nevertheless, the first successful implant treatmentsurvived to us is represented by the renownedmandible fragment with three implanted shellvalves. The Peabody Museum of Archaeology andEthnology at Harvard University had a mandiblefragment from an individual who lived between the7th and 8th centuries AD, with three cuneiformshell pieces in place of the three lower incisors (Fig.

Introduction

THE HISTORYOF IMPLANTOLOGY

Fig. 1 The manual drill used for tooth filing by the Maya.Fig. 2 Upper front teeth of a Maya individual from the 8th century AD.

Fig. 3 Enlargement of the drill tip, originally made of jade and later of copper.

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CHAPTER Iin collaboration with Paolo Zampetti

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TREATISE OF IMPLANT DENTISTRY

4) (4). The fragment was discovered by Dr. WilsonPopenoe and his wife Dorothy during research onthe Mayan civilization at Playa de los Muertos, onthe right bank of the Rio Ulúa in Honduras, whereother important excavations had also been con-ducted by the archaeologist Gordon. In studying this unusual finding, the expeditionmembers at first conjectured that the inserted ele-ments may have been a postmortem cosmetic treat-ment, possibly as part of a complicated funerary rit-ual or religious practice (4, 5).Two years later the fragment was given to thePeabody Museum. Catalogued as N. 20/54, it wasbelieved to be the evidence of a Mayan burial ritu-al, as the three tooth-shaped wedges appeared tohave been inserted posthumously. A few years lat-er, however, the artifact disappeared. It would certainly have been forgotten if the ItalianAmedeo Bobbio, born in Genoa and residing inBrazil, where he practiced dentistry and was profes-sor of Implantology at the University of Santos,hadn’t “rediscovered” it, providing scientific evi-dence that the three shells were inserted during lifeand that they represent the most ancient evidenceof alloplastic implants performed on humans (6).In his capacity as a dental historian, the distin-guished stomatologist wanted to research severalMayan findings that were already well known.Specifically, he wanted to investigate the report of“a black stone” implanted in place of a lateral low-er incisor into the mandible of a skeleton discov-ered almost 80 years earlier by the archaeologist R.R. Andrews among the ruins of the Mayan metrop-olis of Copán (Honduras), and preserved at thePeabody Museum (Fig. 5).In place of this finding, which had unfortunatelyvanished, Bobbio made another interesting discov-ery.

In my search in every sector of the museum, I suddenlymade an unexpected and important discovery: a wide

and compact mandibular fragment, almost the wholebody, more mutilated to the right and without the as-cending branches. The dental formula of the teeth thatare present is as follows: lateral incisor and canine on theright side; canine, premolars, first and second molars onthe left (Fig. 6). The extraordinary thing is that the threemissing incisors were replaced with three implanted ar-tificial teeth made of shell valves. The resemblance to natural teeth is simply astonishing,even if morphologically they have a very flattened an-teroposterior appearance.As a whole, the shape, including the endosseous radic-ular portion, suggests the idea of a triangle lengthenedto form a wedge. . . . In the fragment the natural teethdo not show any sign of decay, but in the natural teethof the left hemiarch small fracture lines of the enamelare visible, mostly horizontal on the labial aspect, butalso vertical ones on the canine. The implants were characterized by a small transversalgroove made carefully below the incisal margin, espe-cially the left lateral incisor. The artificial left incisor is implanted abnormally, rotat-ed on itself at an angle of about 80 degrees, so that thelabial aspect, which has a larger horizontal diameter, ison the side, perpendicular to the other teeth. This is atleast its current appearance, which is clearly visible inmy picture, because the photographs held by the mu-seum, taken in 1935 and slightly blurred, show a muchless pronounced anomaly. It is likely that the tooth fellat a certain point and was thus forced back into this ir-regular position. There is no literature on this mandibleand little or nothing was known until today.However, looking once again through the correspon-dence of the Peabody Museum, I found some informa-tion in a letter dated May 2, 1956 written by the then-director J.O. Brew to the British implantologist BorisTrainin, who had requested details about a “skull withimplanted teeth.” In his reply, Brew indicated that themandible with the three implanted incisors (reportingthe opinion of members of the same expedition) datedback to the 8th century AD, specifying that the teeth

Fig. 4 The Maya mandible found by Amedeo Bobbio.Fig. 5 Original drawing of the lower incisors, published in Andrews’s paper (1893): decayed teeth, with no inlays or cement residue (5 and 6);

the famous implanted lateral incisor, made of black stone (8); decayed bicuspid and large alveolar fragment (8).Fig. 6 Enlargement of the Maya mandible studied by Bobbio.

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were implanted postmortem, perhaps as part of a fu-neral ritual. . . . My point of view is substantially dif-ferent. On June 25, 1970, at the Harvard MedicalSchool I had the fortune to perform the radiographicexamination of all the mandibular teeth for the firsttime (Figs. 7–9). We found incontrovertible elementsthat allowed us to prove the presence of compact boneosteogenesis even around the implanted teeth, whichwere highly stable and were probably inserted with atechnique very similar to the current ones of [Leonard]Linkow and [Giordano] Muratori. Based on the radi-ographic image of the natural teeth, which have incom-plete apexes, and the features of the relatively smallmandibular body, it appears to be a twenty-year-oldwomanly fragment.In conclusion, this would appear to be the first authen-tic endosseous alloplastic implants survived to us, per-formed on live subjects, and which had certainly beenin service for several years (Fig. 10) (4, 6, 7).

Bobbio’s valuable research confirmed the excep-tional fact that 700 years before Francesco Pizarrobrought our “culture” to the New World, CentralAmerican populations already had a distinct civi-lization that was no less evolved than that of Euro-peans (8). It would be interesting to know the surgical tech-nique employed to insert the three implants foundafter so many years and maintained in situ by a bonycompact formation “radiographically similar to the

one that would surround a contemporary implant.”They were unquestionably plunged into freshenedsockets, since Bobbio radiographically demonstrat-ed the bone reaction that led to their inclusion dur-ing life. The time required to prepare the three im-plants could not have been so short that it wouldhave prevented the sockets from healing, unless theinserts were already prepared and ready to fit.Anesthesia should not have been a problem, giventhe ascertained knowledge of North American pop-ulations on the hallucinogenic and anesthetizingproperties of coca leafs and certain types of mush-rooms, nor should it have been difficult to drill thesockets with manual bow drills, probably using thesame “burs” employed to prepare the aesthetic in-lays on the labial surface of the front teeth.

The history of implantology I

Fig. 7 Original radiographof the three “immediate load”shell implants.Fig. 8 The X-ray of thecanine and premolarscontralateral to the area ofthe “implanted” teethdemonstrates that themandible belonged to ayoung individual, given thelarge root canals andradicular apexes.Fig. 9 The X-ray of the leftmolars and premolars of thearchaeological finding; theopen apexes of thepremolars prove that themandible belonged toindividual of about 20 yearsof age.

Fig. 10 This radiographicimage clearly shows the boneinclusion of two valve shellimplants with the formation oftwo new alveolar housingcavities (arrows). Theradiographic appearance isdifferent, as the centralimplant is rotated; it probablyfell and was forced back intoplace.

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The answer to the question of how those first (and,until now, unique) alloplastic implants were tem-porarily fixed during the phase of reparative osteo-

genesis probably lies in the horizontal grooves,which seem to represent the retentive site of a tem-porary ligature.

Fig. 11 The Tridacna used to make the shell fragments for the experiment.Fig. 12 The prepared Tridacna “implants”.

Fig. 13 Flap opening and exposure of the rat tibial bone with the site receiving the shell fragments.

Figg. 14, 15 Endosseous cavities where the shell fragments will be placed.Fig. 16 Close-up of the Tridacna “implant.”

Fig. 17 Insertion of one of the two artifacts.Fig. 18 Rat on the “autoptic” table before samples are taken.

Fig. 19 Macroscopic postmortem image of the bone surrounding the shell fragment three months after surgery.

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Recent and exhaustive histological research on thebehavior of shell fragments in direct contact withbone tissue in animal experiments has confirmedthe principle of osseointegration between the twotissues1 (Figs. 11–23) (9).As to the ability of Maya in carving and adaptinghard stones for the most disparate uses, there is im-pressive documentation of a ritual skull “embel-lished” with perfectly matched turquoise fragments(Fig. 24). A demonstration of the surgical skills ofCentral America’s pre-Columbian populationscomes from a skull discovered in Peru, showingsigns of perforation with rounded edges, partiallyclosed by a bony layer of reossification, which cer-tainly took place during life (Fig. 25) (2, 3, 8).

The Classical Age

We have examples of implant attempts made dur-ing the Classical Age that, unfortunately, are unsup-ported by findings or practical confirmations. Hip-pocrates2 (5th century BC) wrote about the possi-bility of anchoring artificial teeth to the gums usinggold or silk thread in order to replace extracted el-ements, advising the practitioner not to “throwaway mobile elements or teeth expelled from in-jured mandibles, but to put them back in place, ty-


Fig. 20 Sample of the tibial fragment with inclusions.Fig. 21 Another close-up showing the completedosteogenetic process.

Fig. 24 Ritual skull embellished with a mosaic of perfectly fittedpieces of turquoise (London British Museum).Fig. 25 Human skull (Peru, pre-Columbian period) with signs ofsurgical perforation. The partial reossification of the hole proves thatthe patient survived the surgery.

Fig. 22 Histological appearance of the bone surroundingthe “shell implant.” The peri-implant tissue does not show anytrace of fibrous tissue, nor can any evidence of macrophagesbe detected, but it appears to surround the implant withoutgaps in the retention niche (hematoxylin-eosin, 25x).Fig. 23 Magnified detail of Fig. 22 (hematoxylin-eosin, 40x).The peri-implant border is brighter, due to the presence ofnew bone with a higher mucopolysaccharide content,resulting in greater stain uptake.

1 Pasqualini M.E. “Un impianto alloplastico in una mandibola di 1300anni. Ricerca istologica.” Dent Cadmos 2000;11:57-62.

2 Of the entire Corpus Ippocraticum, the most interesting book in whichHippocrates dealt with dentistry is De Carnibus.

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ing them to the remaining teeth with gold thread”(Fig. 26) (1, 10, 11).The same recommendation was also made by AulusCornelius Celsus (1st century AD) who, in De Med-icina, mentioned the possibility of replacing a miss-ing dental element by implanting a tooth takenfrom a cadaver in subjects who, for various reasonshad lost a tooth; however, he did not report if suchtreatment was successful. Nevertheless, it must al-so be noted that the chief purpose of these replace-ments was cosmetic, whereas masticatory physiol-ogy was not given much consideration.

The Middle Ages

During the 10th and 11th centuries, importantcontributions were made by the Arabian school,mainly by Abucalsis (936–1013), one of antiquity’sgreatest surgeons. In his work, Kitab al Tasrif,which is entirely about surgery, he devoted longchapters to dental surgery.3 In particular, he de-scribed the procedures for replacing lost elementswith other teeth—natural or artificial—made ofbony fragments from large mammals, sustainingthat gold ligatures inserted into the gingival tissuewere useful for keeping them in place. In the Middle Ages, an era typified by mortificationof the flesh and vivification of the spirit, very fewdealt with dentistry, but one of them was Guy deChauliac (1300–67).4 In Chirurgia Magna, pub-lished in 1363, he extensively discussed dental is-

sues; Chapter 25, in particular, describes an at-tempt at tooth replantation (1, 12). Casotti (13) wrote that, less than a century later, theFlorentine Michele Savonarola (1384–1461) alsorecommended the ligature of replanted teeth withlinen or silk thread, demonstrating that the practicewas well known, despite the few available books ofthe time. Nicolò Falcucci subsequently illustrated the tech-nique of dental implantation with the aid of metalligatures.5

The Renaissance

During the Renaissance, with the definitive affirma-tion of the field of anatomy various branches ofmedicine gained momentum, and numerousanatomists and surgeons were also involved in den-tistry. One of them was Ambroise Paré, a military surgeonand one of the leading figures of his time, who pro-posed tooth replantation as he was quite knowl-edgeable about maxillofacial trauma caused byfirearms. He noted that it was possible to replantteeth that had been “expelled from their sockets ac-cidentally, tying them to the remaining teeth withgold, silver or linen threads, and keeping them tieduntil stabilization.”Paré’s description of a dental replantation attempt,reported in Vincenzo Guerini’s History of Dentistry,is fascinating. “A trustworthy person confirmed tome that a princess who underwent dental extrac-tion had the tooth immediately replaced with onefrom a young lady-in-waiting. The tooth becamefixed and some time later she (the princess) chewedon it, just as she had done with the tooth that hadbeen removed” (14).The Frenchman Dupont, a contemporary of Paré,introduced a highly original therapy for pulpiticpain: extraction of the tooth followed by immediatereplantation. Dupont’s therapy was adopted bynearly all the best French dentists of that centuryand the one that followed. The granuloma and api-cal abscess that would develop later had not yetbeen connected with pulp necrosis. In many cases,

Fig. 26 Gold “splint” ligature of an Etruscan “prosthesis.”

3 Abdul Quasim al-Zahrawi, latinized as Abulcasis, was one of the first to propose appropriate instrumentation for dental surgery, which he describedextensively in his richly illustrated work; many of the drawings were done by the author.

4 Guy de Chauliac was one of the most important surgeons of the 14th century; a professor at the Saint Esprit Hospital in Montpellier, he was thepersonal doctor of three Avignon popes.

5 Nicolò Falcucci, Sermones Medicales, Venice 1507.6 Gabriel Fallopius, a pupil of Andreas Vesalius (1514–64), was the first to demonstrate that tooth development starts in the fetal period, and he

discovered the dentoalveolar ligament.

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due to fistulization the definitive extraction of re-planted teeth was postponed at length.In Chirurgia, Gabriel Fallopius6 (1523–62), ananatomist in Padua, asserted that if a dental elementis lost or falls, or is extracted for therapeutic rea-sons, the tooth must be healed and then put backin its original site, and fixed to the adjacent teethwith gold or metal wire ligature. If the tooth is notrecoverable for whatever reason, another oneshould be made, reproducing the original shape asclosely as possible, and inserted into the socket.The material recommended for this type of treat-ment is ivory. It is important to note that this seemsto be theoretical rather than practical advice. In-deed, there is no clinical evidence in the literatureof the period and dentistry continued to be prac-ticed by empirics or mountebanks with results thatwere almost always disastrous (11).

The 1700s

Around the middle of the 18th century the work ofPierre Fauchard, considered the founder of moderndentistry, began to make a name for itself.7 In hisseminal work Le Chirurgien Dentiste, ou traité desdents he described five replantation cases and onetransplant. Regarding the latter, he wrote: “Thetransplant was performed on a captain who, as hisleft canine was causing him great pain, asked me ifit was possible to remove it and replace it with atooth extracted from another person. Having re-ceived an affirmative answer, he promptly had some-one call in one of his company’s soldier, who hadbeen advised in advance but whose canine was toolarge.” Lacking anything better to use and being amilitary surgeon at the time, Fauchard extracted thetooth anyway and transplanted it after filing it down. The account continues: “Upon seeing him againeight years later, the captain assured me that thetransplanted tooth had lasted six years, until the de-cay had completely destroyed the crown; he toldme that the root had been extracted by anotherdentist, and not without acute pain.” The decay inthe crown of the transplanted canine was probablyinduced by the filing, which had removed theenamel. Fauchard added that “a small-town colleaguewhose name he could not recall” had suggested a

special transplant technique, consisting of makingsome notches on the root of the extracted tooth sothat, after the transplant, it would consolidate intothe new socket. “By squeezing the root on all sides,[the socket] would insert its excrescences in the in-dentations” so that, “encrusted in this manner, itcould last for a considerable amount of time.” Thesetransplants made from a “donor” to a “recipient” be-came very widespread in Paris in Fauchard’s centu-ry, during which “rich patients bought poor peo-ple’s teeth.” Another description by Fauchard is worth report-ing.

On April 10, 1725 the daughter of Mr. Tribuot, purvey-or to the King, came to me. She was tormented by vi-olent pain caused by decay of the first upper small mo-lar on the right side.8 The girl wished to have the toothextracted to be released from her pain, but she was hes-itant, fearing disfigurement. Thus, she asked me iftooth replantation was possible, as I had previouslydone with her younger sister. I replied that it would beeasy if, during extraction, the tooth did not break, thealveolus did not chip and the gum did not become lac-erated. In the end, she decided to do it. I extracted thetooth very carefully. It did not break, nor did the alve-olus or the gum become lacerated; therefore, I was ableto place the decayed tooth back into its alveolus and tieit to the adjacent teeth with ordinary thread. I kept ittied for a few days, until it definitively stabilized. . . .To extend its life, I sealed the decayed cavity.

Stimulated by the scientific innovation launched byFauchard, in Europe other authors began to exam-ine the same issues. Louis Fleury Lecluse (1754),inventor of the root elevator for third-molar extrac-tion that was named after him and is still very use-ful, stated that he had performed about 300 replan-tations and that many of them were pulpitic teeth.After extraction and healing, he filled the teeth withlead and put them back in the sockets, assertingthat after only eight days they regained their normalfunction (15).Nicholas Dubois de Chemant (1797), dentist toLouis XIV, stated that he favored this therapy forpulpitic pain. Heinrich Callisen (16), who was veryfavorable to replants, wrote that he had successful-ly performed the simultaneous replantation of allthe upper frontal teeth of a lieutenant who had lost


7 Le Chirurgien Dentiste ou traitè des dents, published in 1728, was a milestone for the rise of dentistry and represents the first scientifically structuredtreatise on this discipline. It analyzes several branches of dentistry: the treatment of caries, surgery, prosthodontics, oral hygiene and orthodontics. Italso deals with implants and dental replantations.

8 The “small molars” were the first and second molars.

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them during the siege of Copenhagen. He specifiedthat replantations could be performed only withmonoradicular teeth. At the same time, however,the Englishman Thomas Berdmore, dentist to theRoyal Family of George III, was quite skepticalabout the real usefulness of replantations (17).John Hunter, author of The Natural History of theHuman Teeth, published at the end of 1771, be-lieved that it was possible to extract teeth and boilthem in order to “destroy their vitality” so that, oncedead, they could have no harmful effects and couldthen be replanted to become one with the maxillarybone. He also performed the famous experiment oftransplanting a human tooth with an open apex in-to a cock’s comb, later demonstrating with ananatomical exhibit—exceptional for the era—thatthe vascular tissues of the receiving animal hadgrown inside the pulp cavity of the tooth, whichhad stabilized there and subsequently erupted (18). Toward the end of the 18th century, dentistry num-bered the invention of artificial teeth among itsmain achievements, and this would prove to be ofgreat importance for the future development of im-plantology (19). Several authors dealt with this area and, indeed, asalready noted, the preparation and replacement ofa human tooth with an artificial one was attempteda number of times over the centuries. Various ma-terials were used to manufacture the replacements:the bones and teeth of cows, horses, rams, deer andother animals; mother-of-pearl; ivory; and hip-popotamus, whale and walrus teeth. Allsurgeons/dentists believed that such materials hadaesthetic characteristics coupled with an organicmineral composition that could prevent salivarystagnation, and functional qualities to allow normalchewing and phonetic clarity. It gradually becameclear, however, that such therapeutic measureswere fallacious: cow bone did not satisfy aestheticrequirements and proved to be porous, tending toyellow; cow and horse teeth had a very differentcolor from that of humans; ivory lacked enamel andtended to decompose. Hippopotamus teeth werepreferred and used, as were the rarer whale andwalrus teeth, not only because they had enamel,but also because—once filed—they could easily beadapted to human tooth morphology.

Human tooth replantation merits separate discus-sion. Apart from moral or religious issues, wherebythe use of teeth taken from the dead was consideredprofanation and an insult to the memory of the de-parted, this practice was not universally accepteddue to the serious septic complications for the in-dividual in whom the teeth were implanted, evenafter appropriate treatment and disinfection.9

Nevertheless, it is clear that, regardless of the typeof animal tooth employed, all showed more or lessthe same drawbacks, such as permeability, the ten-dency to soften and decompose, sudden colorchanges, and a terrible stench.In 1764 Alexis Duchateau made porcelain den-tures, but they proved to be very fragile; in 1766Dubois De Chemant then perfected the material bymodifying its composition. Nonetheless, these rep-resented attempts at placing multiple elements atthe same time (18, 19).

The 1800s

It was in 1806 that Giuseppangelo Fonzi(1768–1840) (20) invented the mineral tooth, adiscovery that would be of great importance for thefuture evolution of implant dentistry. His greatestachievement was the idea of manufacturing singleartificial teeth that could be implanted directly intothe socket using platinum hooks, fulfilled impor-tant aesthetic and functional requirements, andwere also chemically unalterable.10

In the wake of Fonzi’s work, during the 19th cen-tury other attempts were made, including the cre-ation of what can be referred to as the first attemptat an endosseous metal implant.This was designed and placed in a fresh human ex-traction socket by the Italian Maggiolo in 1809.Considered French because he practiced in Parisand published his book in Nancy, Maggiolo was ac-tually from Chiavari, in the region of Liguria. Hegraduated in medicine in Genoa and moved toFrance during the period of the Cisalpine Republic.Since his metal implant anticipates many modernconcepts, it is interesting to review the passage inwhich he discussed the concept in his book, LeManuel de l’Art du Dentiste (Figs. 27, 28) (21).

9 The few authors who proposed these methods (Lefoulon, Maury, Dubois De Chermant) asserted that the replanted human tooth had bettercharacteristics than others: higher resistance against the corrosive action of saliva, a better appearance, higher success rates and lower costs.

10 Fonzi called these artificial elements “terrometallic teeth.” In addition to the mineral pastes in use at the time, they were also composed of substancesthat gave them particularly high mechanical strength, consistency and hardness. The main substances employed by Fonzi were kaolin, Limogessilicate, zinc oxide, titanium oxide, manganese oxide, gold oxide. Fonzi noted that he was able to create 26 shades of color by using variouscompounds.

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It often happens that the gold posts securing the artifi-cial teeth to the natural roots remain locked in the boneeven after they are worn out, acting as partial anchors.Therefore, before splinting the artificial crowns to morestable teeth or extracting them, the attempt could bemade to replace the posts with roots made of the samemetal, so that they can become stable within the sock-ets while retaining the artificial crowns firmly, as if theywere placed on natural roots.The procedure is feasible whenever an old root is still

fully inside its alveolus, emerging from it by no morethan half of its length and only if the socket has all ofits natural retention capacity. . . . If conditions are suchthat success is plausible, then one must manufacture anartificial metal root proportionate to the opening left bythe root to be replaced.The dentist should thus have available a series of arti-ficial roots, in the various sizes of the roots of incisors,canines and bicuspids, which are the only teeth whosesockets permit the procedure to be performed.

What follows is a description of their manufactur-ing technique (Figs. 29, 30).

The first piece (no. 11), which we will call the rootbody, is a long thin gold tube whose diameter andheight correspond to the various alveolus dimensionsof the roots to be replaced. One of the tube ends mustbe enlarged by hammering a thin tapered mandrel in-to it. A lateral opening, similar to the one designed formy snap teeth, described previously, is then cut on thisside of the tube (or body).11

A gold plate must be prepared, an oval with the sameshape as the horizontal section of the natural tooth to bereplaced, and a hole the diameter of the larger end of thetube must be made in the center. The two pieces (nos.11 and 12) are then soldered together so that the platehole exactly matches the larger end of the tube and oneof its ends is positioned over the notch on the tube. Itstwo ends must be curved slightly to fit the margins of thealveolus opening as precisely as possible. Then a secondsmall gold tube must be prepared, with a diameter sim-ilar to the one of the opposite and thinner end of thetube. It must be cut into four sections, being sure to keepits upper extremity intact, as this will bring the four sec-tions together into a sort of ring.The four wings are then reduced and separated fromeach other with a file. At this point, they will be curvedto form a sphere resembling the one shown in drawingno. 13. The small sphere must now be inserted ontothe thinner end of the tube, so that two thin wings cor-respond to the larger ends of the elliptic plate and theother two to the smaller ends (21).

The author specifies that the four wings of his smallsphere must be placed so that two of them are ori-ented according to the long axis of the elliptic plateand the remaining two toward the short one, in or-der to adapt them roughly to the apical third of theroot being replaced.


Fig. 27 The original cover of Maggiolo’s treatise (1809).Fig. 28 Maggiolo’s diagram for manufacturing dentalprostheses and the endosseous implant.

Fig. 29 Original diagram for manufacturing the endosseousimplant.Fig. 30 Gold casting made according to the original diagramfor the modern reproduction of this artifact.

11 Maggiolo is referring to the first part of his book, describing his newtechnique of “snap” artificial crowns, which are accurately portrayedin the second series of sketches in Fig. 28.

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The ring connecting the four wings must then be sol-dered to the thinner tube section. The ends of threethin wings will also be soldered halfway on the tube;further ahead I will explain why the fourth plate is notsoldered like the others. The three pieces, which—once soldered—will give the implant its shape, mustbe made of 18K gold, not only because this alloy issolid enough, but also because does not cause anyproblems and remains inside the alveolus (Figs. 31,32).

Maggiolo deduced this because, in his opinion,“the gold posts of artificial teeth could harmlesslyremain the sockets even after complete resorptionof the natural roots.” His explanation continues indetail.

Now that our artificial root is ready, we will preparethe site for its insertion. The old root must be extract-ed. Since damage to the socket walls must absolutelybe avoided, it will be firstly divided into three pieces,using forceps with sharp beaks, suitable for its longi-tudinal separation. One beak must be introduced in-to the root canal, forcing the other one from the out-side, perpendicular to its axis. Firmly snapping theforceps will split the root up to the apex. The pieceswill then be removed with watchmaker’s pliers andextracted with gentle and gradual movements, with-out injuring the gum or fracturing the socket. Theprocedure will require a few minutes of patience, but

this is of little importance when the dentist’s objectiveis to succeed. In fact, it is advisable to avoid hastewhen extracting teeth or roots.12 After the root hasbeen removed (and the patient has rinsed his mouthwith solution of equal parts water and vinegar), theartificial root must be inserted into the empty socketvery carefully. Its base, formed by the oval plate, mustbe pushed below the gum, which will quickly shiftabove it. Attention should be paid to ensure that thenotch on the larger portion of the tube is rotated to-ward the inside of the mouth.13 The artificial root willthen be forced into the socket until it reaches the bot-tom. Positioning the thumb toward the index finger,placed in the oral cavity, gradually but firmly com-press the socket walls against the metal root. Thecompressions must be repeated for two-three weeks. The patient should be advised not to displace the ar-tificial root; he must rinse with astringent alcohol so-lutions while the artificial root gradually becomesfixed in the alveolus.Numerous examinations have demonstrated that, af-ter extraction, the alveolus walls do not preserve thecentral cavity for a long time, but progressively closeit as they move toward each other.My artificial root is stable for several reasons. If thealveolus walls have not been fractured during extrac-tion, it is easy to see why, during healing, they will fa-cilitate its fixation inside the newly formed bone. Furthermore, since the artificial root is thin below theoval plate and consists only of the smooth portion ofthe tube and the small sphere, the alveolar bone wallscan converge and close around the root, increasing itsstability, so that the only way to remove it later will beby fracturing the socket.I already mentioned that one of the four sphere wingsshould not be soldered to the tube like the others.Sometimes, in fact, the sphere can be slightly largerthan the alveolar cavity, preventing the artificial rootfrom reaching the bottom of the alveolus and makingit less stable. However, our compression of the alveo-lus forces the free wing against the bone wall like aspring, thus providing further fixation, a crucial con-dition for the success of the procedure. The artificialroot proves to have achieved sufficient stability when,gently pressing on its outer surface, it does not moveeven when the pressure is applied to the gum. Thisproves that the alveolus is stabilizing it permanently.It is not a good idea to immediately insert the snaptooth, which should not be fitted to the artificial root

Fig. 31 Schematic drawing of Maggiolo’s implant placed in the post-extraction socket.Fig. 32 The principle of “osseointegration” according to Maggiolo.

12 Maggiolo’s recommendations prove that the surgeons of the early 19th century were already using anesthesia that could guarantee slow enoughwork time and thus the accuracy of the procedures. Sulfuric ether vapor was already in use and Davy had published his work on the anesthetizingproperty of nitrous oxide or “laughing gas” nine years earlier.

13 The “notch” allowed the snapping insertion of the artificial tooth. Since it was rotated toward the mouth, the snapping mechanism was not visible.

31 32

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until it has achieved maximum stability; otherwise, allof our good work will have been vain.Therefore, I recommend that the snap tooth not be in-serted until another month has elapsed from the timecomplete fixation of the artificial root has been ascer-tained, so that it (the tooth) cannot alter the stabilityof the root.This procedure does not cause any problems becausethe healing tissues can easily enter through the metalvents.The procedure can be considered one of the finest ex-amples of dental art, because it has such importantadvantages that, for some time now, I have neverfailed to consider the option of employing it. I havealmost always achieved very satisfying results, bothfor the persons I have treated and for myself.

This is the report of the first endosseous metal im-plant, translated from the book written by Maggi-olo, “inventor”—as he defines himself—and doc-tor of surgery of the University of Genoa, and al-so Member of the Medical Society of Lyon (Figs.33–35).The Maggiolo implant was also cited 36 years lat-er in William Roger’s Encyclopédie du Dentiste(1845). Roger warns that the “Maggiolo experi-ments” must be monitored constantly and cleanedfrequently with disinfectant mouthwash “becausethey cause teeth mobility, a bad smell and pain.”He also mentioned the case of a patient who, de-spite such precautions, “couldn’t wait to have theartificial root removed, as it was real torture!”Roger’s criticism notwithstanding, Maggiolo’s “ar-tificial root” represents the first metal implantused to replace lost human teeth. His implant pre-cedes ours by nearly two centuries and, despite

the limited surgical possibilities of the time, thelack of anesthetics and antibiotics, and the com-plete lack of occlusal knowledge, it essentially en-compasses many of the concepts that developedduring our era and are wrongfully considered theexclusive and original brainchild of some of ourcontemporary colleagues.In fact, Maggiolo’s artificial root prefigures:1) the principle of osseointegration by new bone

apposition through and above the emptyspaces of vented structures made of metal;

2) the principle of reparative osteogenesis protec-tion by the “two-step submerged implant”technique;

3) the search for primary stability as the sine quanon condition for osteogenesis.

It had limited success due to a combination of thefollowing concomitant factors:1) the non-biocompatibility of the 18K gold alloy,

containing cytotoxic materials such as copper,and the even more cytotoxic alloy employed forsoldering;

2) the lack of effective anesthetics, antiseptics andanti-inflammatory agents;

3) the fact that it was impossible to conduct radi-ographic checkups of the sockets, any wallfractures and/or the possible presence of apicalgranulomas (the roots to be extracted, dis-cussed by Maggiolo, had never been treatedwith appropriate root canals!);

4) the limited availability of properly shaped met-al structures fitted for the sockets.

In the United States, dentists—who since the 19thcentury had been at the forefront of dental sci-ence—conducted numerous implant attempts andexperiments.


Fig. 33 Reproduction of the implant. Fig. 34 Another close-up.Fig. 35 Original drawings of the artificial tooth for insertion into the implant (1809).

33 34 35

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Around the 1840s Chapin A. Harris and HoraceH. Hayden, founders of the Baltimore College ofDental Surgery (1840), attempted endosseous im-plants employing iron teeth of their own design(18).Harris, in particular, was the first to place a lead-coated platinum post in an artificial socket “to re-semble the root of a natural tooth.” Harris had al-so roughened the lead in order to provide the re-tention for the “new” tissue that was supposed toform inside the artificial cavity. After removing theligature used for temporary splinting to the adja-cent teeth, he placed a porcelain crown on thatimplant, an operation that—in his opinion—wassuccessful.Today we know that lead is not biocompatible. Re-active and inflamed hypertrophic tissue must haveformed around that implant, giving the illusion oftemporary stability. Three similar implants (placed in surgically pre-pared sockets) were also performed by Perry andEdward (1888 and 1889), and reportedly wereequally successful.Slightly different implants, also lead-coated, wereperformed by Edmunds in New York. He report-ed that on October 21, 1886, he had “implanted”a platinum “capsule” coated with lead and rough-ened with a drill. Four years later, on March 12,1889, he performed a similar operation at thedental clinic of the First District Dental Society ofthe State of New York during the Society’s annualcongress. It is interesting to note that during thesame year he worked on his colleague Juan JosefRoss, from Guatemala, placing one of these im-plants in an artificial socket made near an upperincisor that have fallen out years earlier. He re-ported that four days later Dr. V.H. Jackson, whohad attended the surgery, had ascertained that theartificial tooth “was still in place and showed re-markable stability, with no apparent irritation ofthe surrounding tissues.”Lead is, in fact, a much more cytotoxic elementthan the 18K gold employed by Maggiolo. Thechoice of lead as coating material for the internalplatinum frameworks was probably due to the factthat it is easy to use. In fact, it can be melted(327.46°C) and poured into cavities similar tothose made by drilling the edentulous ridges.Moreover, before it hardens completely, the inter-nal platinum framework can be easily immersedin it. It is also very easy to roughen, modify and

adapt in the event of emergencies (22).Harris, Perry, Edward and Edmunds may haveemployed lead because it cannot be attacked bysome of the most corrosive acids, failing to consid-er its high toxicity. Indeed, it is a tricky and pow-erful poison that has been known to cause intoxi-cation since antiquity. Hippocrates identified it aswhat had poisoned a galena miner; Pliny the Elderdescribed its toxic effects on slaves forced to dothe same work. Even when lead was being testedas an implant material, the effects of saturnism inworkers who had daily contact with the element(such as typesetters) were well known.In the same year in which Edmunds inserted hisfirst lead-coated platinum capsule (1896), Lewisimplanted a porcelain tooth with an internal goldsupport, thus assuring of a successful outcome aswell! Two years later, the German Znamensky de-scribed some of his experiments with endosseousimplants made of “carved porcelain,” rubber andgutta-percha. In March 1895, William Bonwill reported to theFirst District of the Dental Society of the State ofNew York that he had successfully implantedpierced tubes as well as solid gold and iridiumposts in artificial sockets, used “to replace individ-ual teeth and restore full dental arches.” Bonwill’simplants represent a step forward in the evolutionof such attempts, because he used pure materialssuch as 24K gold and iridium, which are virtuallyincorruptible, and employed them not only to re-place individual teeth, but also to add artificialabutments to multiple tooth prostheses. Bonwill’stechnique was also adopted by Gramm, who like-wise used solid pierced cylindrical implants madeof 24K gold and/or iridium.In the implantology field, Payne is the last authorof the 19th century and the first of the 20th. Heused silver “capsules”14 and gave a practicaldemonstration at the 1908 American Dental Asso-ciation Congress. Accepting the validity of Payne’s silver capsules isdifficult, but since he gave other public demon-strations of the method three years later, we canassume that, at least for a while, the implants andporcelain structures showed sufficient stability. Although these cases cannot be considered full-fledged success stories, it must be stressed thatduring this century, figures from Maggiolo toPayne progressively attempted—at least on a con-ceptual level—to use increasingly “inert” materi-

14 Payne’s “capsules” were similar to the vented tubes of Bonwill and Gramm, the only difference being the material: silver in place of 24K goldand/or iridium.

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als, and this was paralleled by the development ofthe concept of inserting alloplastic roots with a re-tentive morphology.Other attempts were made by several authors. In1870 Rogers tried to place metal implants in thejaw; in 1888 Lewis made and used a platinumroot-shaped implant with a porcelain crown, fol-lowing impression taking of the alveolar cavitywith a plaster-based material. In 1890 Léopold Ollier proposed platinum andnickel-plated steel screws as an osteosynthesismeans, but it remained an isolated experimentwhose application was more useful for orthope-dics and traumatology than it was for dentistry.In 1891 Wright designed a porcelain tooth with aporous root in order to facilitate its fixation with-in the socket. On the basis of this experiment, thefollowing year Friel replicated the model, provid-ing the root with a certain number of holes con-nected to each other by a central channel thatopened at the crown to facilitate drainage in theevent of an apical abscess (18, 23).

The 1900s

The early 20th century was marked not only byPayne’s renewed attempts to employ his silvervented cylinders, but also Sholl’s first porcelainroots, “roughened” in order to increase retention.While not as biocompatible as studies would at-tempt to demonstrate even 70 years later,15 porce-lain was nevertheless a better material than theones proposed previously.The first artificial porcelain root, inserted in August1903, was checked in November of the followingyear and showed good stability. Nevertheless, it isimportant to note that the artificial crown placedon the implant had been blocked with two splint-ings to the crowns of the adjacent teeth.16

This brings us to E. J. Greenfield’s “two-step” cages(1913), which anticipate the evolution of modernimplantology, despite their flaws (Figs. 36–40) (24,25).Casto in 1914 and Kauffer in 1915 placed spiral-shaped implants, both stating that they were satis-


Fig. 38 Magnified view of the basket. Fig. 39 Greenfield’s prosthetic technique.Fig. 40 The surgical cut made with a Greenfield drill implicated leaving the central bone core (original drawing).

Fig. 36 Original drawing of the Greenfield drill for the endosseous basket (1913).Fig. 37 X-ray of a Greenfield basket, which is perfectly osseointegrated.

15 See the results of Pasqualini’s studies on animals, described in Chapter 2.16 As temporary stress breakers for long bridges, they used the implants of Sholl and Brill (1926–32–36), as well as those of A. Hurska Jr. (1936),

albeit with minor variations.

36

38 39 40

37

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fied with the outcomes. After World War I, the Frenchman H. Léger-Dorez(1920) designed a “tubular extension” implant(Fig. 41) that was conceptually similar to the mod-ern expandable screw in its forced anchoring intothe bone. With this kind of mechanical compres-sion, he believed he had designed an important in-novation, as he thought that his implants could bestabilized immediately, even before “biological” en-capsulation through reparative osteogenesis.The materials for his four-piece “tubular extension”implant were made of 24K gold for the body andplatinum for the internal expandable screw. As wewill see later, the failure of those implants (andsimilar ones that we will examine) lay precisely inmechanical expansion, which was rigid and forcedbeyond the endurance of living bone tissue. That year, Weigele placed a frustum-shaped pieceof ivory into artificial sockets, protected by mucosasutured over it; the ivory should have promoted aslow resorption reaction by ankylosis, one thatwould allow the temporary load of a post crown tobe inserted subsequently. Years later, Weigele re-ported that he had used his ivory cones as en-dosseous overstructure supports for the temporaryanchorage of lower complete dentures. Concern-ing this method, which is limited time-wise by theinevitable rejection of ivory by human bone, wemust emphasize the important principle of the“two-step submerged” implant, anticipated byMaggiolo a century earlier, followed by Greenfield(1913) and Alvin Strock (1933) in the first half ofthe 20th century.In the attempt to create solid and resistant inclu-sions coated with materials he believed were inert,Abel (1934) used Vipla vitrified steel and “reticu-lated” platinum cylinders coated in porcelain.With the same hope of finding—at last—the idealbiocompatible material, Wuhrman (1937) usedvented platinum structures, assuming that it wasinert, given that it was a pure element with a highmolecular weight. The idea was brilliant, but un-successful.In 1938 the U.S. patent office granted P.B. Adamsexclusivity for a “two-step” implant for the “spher-ical” anchorage of removable prostheses (“Anchor-ing means for false teeth”). The implant had noluck but, re-examined today, it closely resemblesthe osseointegrated implants presented by theSwede Per-Ingvar Brånemark 40 years later (Figs.42, 43).Why did the implant fail? The main reason residesin extremely low biocompatibility of the materialsthat were employed, coupled with the lack of prac-tical clinical demonstrations.

Fig. 41 The Léger-Dorez implant (1920).Fig. 42 P. B.Adam’s original drawings for the patent of hisimplant system (1938).Fig. 43 This prosthetic anchorage technique has changedvery little in 70 years.

41

42

43

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In 1938 Gustav Dahl, also Swedish, attempted asubperiostal mandibular implant, inserting fourmetal posts on which he later anchored a prosthe-sis. It is important to note that, after this attempt, theSwedish Dental Society asked him to refrain imme-diately from performing the treatment—the penal-ty being expulsion from the society—just when theprocedure seemed destined for success (26). In 1939, in Boston the Strock brothers began hu-man testing with screws made of Vitallium, a

chromium-molybdenum-cobalt alloy that they hadalready tested on dogs. Their scientific reports about their experimentswere characterized by modesty, prudence and ele-gance, and despite the fact that they represent yetanother milestone in the evolution of implantol-ogy, they remained virtually unknown and weremistaken for the many failures of other methods(Figs. 44–51) (27–29).In 1941 Glenn D. Irwin again proposed a post-ex-tractive “rapid-expansion” implant that, like the


Fig. 44 Alvin Strock and Marco E. Pasqualini in 1985.Fig. 45 A copy of the original publication on Strock’s two-step submerged implant, with a dedication to Ugo Pasqualini.

Fig. 46 Strock’s two implant morphologies; they are submerged implants (1948!).Fig. 47 Original pictures and radiographs of a Strock submerged implant that is perfectly integrated (1948).

Fig. 48 Detail: agenesis of the lateral left upper incisor (original).

Figs. 49, 50 X-ray magnifications (original).Fig. 51 Strock’s threaded screw. Left: the screw immediately after placement in a post-extraction socket.

Right: complete healing of the bone is visible at three months.

44

46

49 50 51

47 48

45

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previous one devised by Léger-Dorez, did not havemuch success.The following year Gunhtert used gold-palladium-silver alloy implants, citing that they offered highresistance to fracture, great elasticity (which heconsidered useful in adsorbing occlusal loads) andthe absence of reactivity with the host tissue.In the 1940s Jean Lehmans successfully placedsome very original implants, which he named “ex-pandable arch” implants, demonstrating their pos-itive outcomes radiographically; these implantscould also be placed in thin edentulous ridges(Figs. 52–54) (30). His implants, made of tanta-lum—whose biocompatibility had already beendemonstrated in orthopedics—for the first time,were composed of a threaded pin with a thin elas-tic circular band inserted into it and kept in placeby two nuts (also threaded), respectively in its“apical” and “occlusal” portions. When turned, thetwo nuts could extend the band toward the bonegroove ends in which the implant had previouslybeen placed. Therefore, it was locked even beforesecondary stability occurred due to closure of thegroove through reparative osteogenesis. The elasticpressure of Lehmans’s expandable arch wasenough to stabilize the implant without causing is-chemia beyond the bone’s reactive capabilities. In the history of implantology, this represents thefirst attempt to use a bone groove in place of acylindrical bore. The groove was created by a se-ries of thin vertical tunnels that were then connect-ed by mean of a fissure bur. High-speed drills didnot exist at the time and, consequently, these stepswere mandatory. Nevertheless, Lehmans’s implantwas not very successful, although the author pro-posed it again a number of times after the middleof the century: in 1959, 1960 and 1961 (30).In 1946 Meylan also patented a more complicated“wire spring” implant that exploited the elasticpressure of two steel looped wires placed in a largeartificial alveolar cavity, where they were spread by

the progressive screwing of two bolts.Other experiments were also made by immersingartificial roots in thermosetting or self-curingacrylic resin. The following tests were performed:a) inclusions of roots made of thermosetting resin,

manufactured from the impression of fresh ex-traction sockets, by Charad-Nur, (1948) andRossi (1949);

b) inclusions of self-curing resin, placed while stillin a soft state in surgically undercut sockets, byKelly and Rottemberg (1948). After the self-cur-ing resin had been pressed into the cavities andundercuts, but before it hardened, a post wasinserted in the cavity for the future artificialcrown, or the crown was fitted with a retentivepost, which rapidly became one with the self-curing resin placed there a few seconds earlier.The unavoidable overheating produced by resinpolymerization was compensated—at least intheory—by a water-cooling jet.

These authors were not the only ones who, attract-ed by the novelty of the plastics that had alreadybeen used experimentally in ophthalmology andorthopedics, attempted to perform such proce-dures. Nonetheless, since similar attempts contin-ued in the second half of the century, they will bediscussed ahead.In 1946 Norman Goldberg and Aaron Gerschkoffproposed Vitallium juxta-osseous implants, in-tended mainly for use in the lower jaw; they wereset on the mandibular ridge and kept in place byscrews (Figs. 55–71) (31, 32).The year 1947 is historical, as it marks the birth ofmodern implantology. On February 27 of that year,at a conference held at the AMDI (Italian DentalAssociation) in Milan, the Italian Manlio Formiggi-ni proposed the hollow spiral screw in stainless-steel wire or tantalum, a white-silver materialwhose technical use could be veritable torture. Itsdesigner named the method “direct endoalveolarinfibulation” and it marked the definitive transition

Fig. 52 Lehmans’s original drawing. Fig. 53 53 Examples of Lehmans’s endosseous implants.Fig. 54 X-ray of an arch implant (1959).

52 53 54

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to the era of endosseous implants (Figs. 72, 73)(33).

The screw I designed for intramaxillary infibulation ismanufactured with a wire made of unalterable materi-al, with a thickness of 1-1.2 mm, bent to form a spi-ral around a central axis that stabilizes the system. Thecentral axis is fixed at the apex of the spiral because itforms its extension, whereas at the base it is solderedto the free end of the spiral, thus allowing the forcedscrewing of the implant into the anatomical or surgi-cal socket. Therefore, my designation of ‘hollow screw’seems justified, as the screw pitch is, so to speak, free

and suspended, but stabilized by the central shaft(33).

It would be interesting and, indeed, crucial for thehistorical knowledge of implantology to quote thewhole report that Formiggini gave in Stresa in1952, when he presented several clinical cases andbrought with him two patients who chewed—problem-free—with fixed prostheses cemented onhis “infibulations.”

Before starting my speech, I would like to thank theBoard of Directors of the Dental Association for giving

Fig. 55 Severe periodontitis in a 29-year-old woman.After complete edentulation and healing, Luigi Marziani of Rome placed two totalsubperiosteal implants (1955).

Fig. 56 The inferior implant made of tantalum. Fig. 57 Preparation of one of the two mesh plates.

Fig. 58 Latero-lateral X-ray of the two mesh plates inserted. Fig. 59 Frontal X-ray.Fig. 60 Patient’s profile before and after.

Fig. 61 Appearance of the mucosae before insertion of the Dolder bars on the threaded abutments of the implants.Fig. 62 Close-up of the healed soft tissues. Fig. 63 Placement of the prosthetic splinting bars.

Fig. 64 The two definitive overdentures (1955).

55 56 57

58

61 62 63 64

59 60

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me the honor of presenting the results of my studies ina field where other scientists already made several at-tempts, always with negative results.17

The replacement of permanent teeth that have beenlost following trauma or expulsive diseases, or havebeen surgically removed has long been the dream ofpatients and stomatologists. And now, if I weren’t afraidof being overly modest, I would say that, with themethod I am going to present, I am confident that Ihave fulfilled this aspiration. For the idea of designing my system, I can thank thenegligence of a client whose upper canine I extracteddue to periodontitis and a periapical abscess. After ex-traction, I inserted an iodoform pledget into the sock-et, advising him to keep it in place and come back thefollowing day to have it removed. He instead returnedtwo months later, swearing that the drainage was stillin place! This seemed odd to me and I checked it care-fully: the oral mucosa was absolutely normal and theaccess to the alveolar cavity appeared to have closed al-most entirely by then. After inserting a probe withsome difficulty, I felt the pledget, which I promptly re-moved. The extraction was difficult, painful and

bloody, because connective tissue had grown betweenthe iodoform gauze meshes, fixing it to the socket wall.I was surprised by the fact that the gauze had not beenexpelled as a foreign body and had not caused inflam-matory reactions.At this point, I thought that the gauze could be re-placed with a similar but unalterable material. There-fore, I prepared a small roll of steel wire netting, whichI experimentally introduced into the fresh socket of an-other patient. The result was negative, because thesmall roll was soon expelled. Consequently, I under-stood that it was not simply a matter of introducing aforeign body into the socket, but of keeping it in placeat all cost.

Fig. 65 The same patient 52 years later! Fig. 66 Upper denture in place of the subperiosteal implant, which was removed in 1997 dueto oroantral communication after 42 years of service. Fig. 67 Healing and healthy appearance of the palatal mucosa.

Fig. 68 Lower overdenture still working with the subperiosteal implant (2007).

Fig. 69 Dehiscence of the tantalum implant placed in 1955, without any complications for the patient.Fig. 70 Bar and dehiscence (2007). Fig. 71 The prosthesis with latch attachments still in service after 52 years!

17 At the time of his report (right after World War II) Formiggini could nothave been aware of the results of the Strock brothers’ studies.

Fig. 72 One of Formiggini’s first screws (1947).Fig. 73 Close-up of the Formiggini spiral.

65

69 70 71

66 67 68

72 73

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With that in mind, in place of the small roll I designeda stainless-steel wire screw (which could be also madeof other unalterable metals, preferably tantalum—if itweren’t so expensive [in Italy]). My screw can be manufactured in two ways: with asturdy wire with a diameter of about 1.8 mm, rolled in-to a slightly conical spiral and ending at the base witha short straight portion parallel to the axis of the cone,or with a thinner wire with a diameter of 1.2 mm,shaped like the previous one but with the addition ofa central axis made of the same wire that, starting at theapex of the spiral, extends to the opposite end, whereit should then be connected using a spot welder or, bet-ter yet, ordinary soldering. For fixation and elasticityreasons, I choose the latter type of spiral and I startedexperimenting on an old man from a nursing home inModena, from whom I requested the utmost confiden-tiality.Unfortunately, this happened toward the end of 1943,when I was suddenly forced to leave Modena becauseI had been issued a double arrest warrant.18 I fled tonearby Bologna under the assumed name of Manfre-dotti, and for 17 months I organized and directed thehealth services of the local partisans. In the meantime,my office was invaded by the armed forces of the Ital-ian Social Republic, who also confiscated the notes Ihad gathered on the subject, along with my profession-al material.When I returned after the liberation, that first patientof mine had died along with his secret. At that point,and with far greater peace of mind, I resumed my stud-ies. Today I present myself to you, dear Colleagues, withthis introductory note and my report on three success-ful cases. Before illustrating them to you, I wouldbriefly like to discuss the surgical technique for thistype of implant. It can be placed in fresh and artificial sockets alike, asa support both for single crowns and prosthetic de-vices. Before inserting the screw into the artificial or naturalsocket that will host it, it must be flame-sterilized with-out heating it to red hot and must then soaked in iod-oform powder, which the heat will melt to form a su-perficial layer of antiseptic varnish. The screw mustthen be inserted in the socket by screwing it forcefully,as you would with an ordinary screw, until all you cansee on the surface are the straight ends, which are

welded together and designed to act as the bearing postfor the future prosthesis.Obviously, when extracting the tooth to be replacedwith my system, it is advisable to measure the thick-ness and length of its root with a compass and a probe,in order to obtain a reference in choosing the implant,which must be slightly larger, because it is essential thatit create its own accommodation within the correspon-ding socket walls.It should be borne in mind that the screw or, rather,the spiral must be inserted deeply, until it is complete-ly contained within the socket cavity. On the outside,the two ends forming the central shaft are all that willprotrude, but only in part. The procedure is differentwhen an artificial socket needs to be prepared.Following anesthesia, a small incision is made in thesoft tissues up to the periosteum. A cavity resemblinga socket must then be made in the bone, initially usinga round bur and subsequently widening the bore witha commercially available drill, the type the French calla couteau de Rollins.19 All that remains to be done at thispoint is insert the selected screw promptly, followingthe same procedures employed for the previous case.I have never observed the slightest inflammatory reac-tion with my procedures, although a few days afterplacement the screw can become slightly mobile. It canbe fixed again, screwing it in until it is stable. You should not expect absolute stability immediately,because it will be achieved later, when granulation tis-sue has formed between the elements of the spiral.Bone tissue will subsequently obliterate the alveolarcavity. The best timing for applying the prosthesis is left to theoperator’s discretion. Regarding impression taking, there are no special rec-ommendations. It is performed as done for a commonpost crown, but to facilitate this operation, the protrud-ing end (the bearing post) can be covered with a smallstainless-steel tube, which will be retained in the im-pression material and subsequently become part of theprosthesis, preferably made of synthetic resin. Esteemed Colleagues, I would like to ask you to exam-ine the radiographs of three cases I treated using themethod I just described. I would have liked to have mypatients here with me, but current conditions made thisimpossible.20 I must also confess that I would also haveliked to present statistical data with a larger number ofcases but, as I am sure you can easily understand, I


18 The double arrest warrant for Formiggini was a result of the racial laws against Jews that had just been enacted by Mussolini, who embraced thecriminal theory of his German ally. Formiggini’s father, humiliated by the measure, killed himself by jumping from the bell tower of the Cathedral ofModena.

19 Similar to Ottolenghi’s drills.20 For his second report, given five years later at the Italian Dental Congress in Stresa (1952), Formiggini brought in patients wearing implants.

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could not have expanded my study without running therisk of the information getting out.Two intraoral films refer to two young patients: the firstone is of a certain Z.G., 20 years old, from CastelfrancoEmilia and a soccer player, whose central left incisor Iextracted on October 31, 1946; I then placed one of myscrews on November 22. On January 3 I completed theprocedure with a tooth made of synthetic resin. The de-lay in applying the tooth was due to the fact that the pa-tient had urgent business to attend to and was unableto come. There was no immediate or late inflammatoryreaction. The radiograph, taken one month after thescrew was inserted, shows a small area of bone resorp-tion due to a previous suppurative process, but also thetendency toward the formation of bone tissue betweenthe screw pitches.The second radiograph is of a certain V.G., a 22-year-oldfrom Finale Emilia, who on November 13 underwentextraction of the upper left canine, followed a few dayslater by screw insertion, which was then completed onthe 30th of the month with a crown made of syntheticresin. The radiograph, taken just 20 days following in-fibulation, shows the tendency to encapsulation by thenewly formed tissue, although an area of bone rarefac-tion persists at the alveolar apex, due to a previous pe-riapical abscess. No inflammatory reactions.Nevertheless, the most demonstrative case is the thirdone, a certain M.G., a 40-year-old from Cavezzo and aregular client, who was wearing an upper left four-ele-ment gold bridge supported by the first premolar andthe second molar. Due to septic periodontitis of the sec-ond molar and the wisdom tooth, I had to remove thebridge and extract the two distal molars. I consideredreplacing the distal abutment tooth that I had just ex-tracted with one of my implants, and of the three avail-able alveolar cavities I chose that of the second molar,since its axis was parallel to the front abutment. I theninserted the screw. Again in this case, as in the previous two, there was noimmediate or late inflammatory reaction. The onlything I was forced to do was turn the screw once eightdays following insertion, in order to further stabilize itfurther. The first radiograph, taken 25 days after surgery,showed that the bone tissue was still rarefied around thescrew. Consequently, I felt it best to wait 20 more daysbefore applying a four-element bridge, the anterior ofwhich was a gold crown, whereas the other three, dis-tal, were gold-resin crowns.The second radiograph, taken 40 days later with theprosthesis in place, shows the crown, the metal prosthe-sis structure and the screw, around which (and this isthe most interesting aspect) we can already observehealthy bone tissue that is invading even the spaces be-tween the screw pitches. This demonstrates that not on-

ly did the osteoporotic reaction typically found in thepresence of a foreign body fail to occur, but that a repar-ative process and reossification of the alveolus had al-ready started. From a functional point of view, I can as-sure you that my patient, like the others, is enthusiasticabout the prosthesis and can chew without any pain.I hope that my simple report and the modest case studywill suffice to prove the validity of my method. I amconfident that the successful outcome of my first threecases will soon be confirmed by my future experiencesas well as yours (Figs. 74–80) (34).

Despite the veracity of the concepts it expressed, thereport left itself open to criticism from many whowere more accustomed to scientific presentations.And this is inevitably what happened!The dental world was experiencing a justified peri-od of cautious skepticism toward endosseous im-plants and hope instead lay in the possible successof the very recent technique of subperiosteal im-plants. As a result, failures (due to technical mis-takes made by Formiggini’s first disciples) were giv-en greater consideration than successes when itcame to official judgments (35, 36).This method was later accepted with only a few ex-ceptions, and more so abroad than in Italy. We willalso see how the modifications made by his pupilsallowed a large number of patients to enjoy the ben-efits of the implants that originated from his ingen-ious innovation. Some of these modifications—above all those madeby Carlos Perron Andres—were limited to replacingthe two vertical portions of the screw with a singlemetal portion that was thicker and more rigid (Figs.81, 82).At the beginning of the century Perron Andres pro-vided many radiographic demonstrations of the va-lidity of Formiggini’s “hollow spiral,” which theSpaniard improved slightly, though strictly in termsof the solidity of the external prosthetic abutment(37).The only difference between Formiggini’s originalspiral (the two small external portions had to bejoined using a spot welder or soldering) and in Per-ron Andres’s version the two portions were replacedby a single fused block. Nevertheless, over the yearsthis method gradually and definitively became es-tablished, gaining widespread consensus, and stud-ies were conducted on the histological reactions ofthe tissue involved in the implant treatment (Pini,Zepponi, Sordo, Gola, Roccia, Marziani et al.). (38).During the 1950s Blum made a few—but unsuc-cessful—attempts at using self-curing syntheticresin in the socket, in which the implant was placedbefore the resin hardened completely. However, the

39

experiments were soon abandoned due to the toxi-city of the compound (18). At this point, we would also like to mention the con-tribution made by the Dental Clinic of the Universi-ty of Pavia, as we are currently conducting a histo-riographical overview to shed light on the many sci-entific studies conducted over the course of 90 yearsof activity. The Associazione Europea Odontostom-atologica per gli Impianti (European Dental ImplantAssociation) was founded at the University of Paviain 1955, and experimental and histological studies

were conducted here (Palazzi, Borghesio, Branchini,Piazzini, Continolo). Vitallium implants were em-ployed, i.e. the type that had already been used pre-viously; as noted, this alloy is made of cobalt (65%),chromium (30%) and molybdenum (5%) (39–41).It was also during the 1950s that Flohr experiment-ed with implants made of steel-reinforced resinscrews (42), whereas in 1961 Stefano Tramonte wasthe first to propose the self-threading screw inchromium-cobalt-molybdenum and chromium-nickel-molybdenum; he was also the first in the


Fig. 74 Two Formiggini spirals in service since 1952 and checked in 1981 after other implants were inserted.Fig. 75 Close-up of the previous image.

Fig. 76 Detail of the X-ray: excellent adhesion of the bone tissue around the spiral (1960).

Figs. 77, 78 Formiggini spirals, loaded and unloaded (1958). Fig. 79 Image immediately after placement into the socket.

Fig. 80 An excellent radiographic image of one of Formiggini’s screws, still working perfectly in 1985.Figs. 81, 82 The Perron Andres implant.

74

77

80 81 82

78 79

75 76

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world to employ titanium as implant dentistry ma-terial (43). The following year Muratori presented“hollow” screws, which represented a further im-provement of Formiggini’s screws in terms of shape,structure and surgical technique (44). In the late 1950s and early 1960s, in France RaphaelCherchève further modified the design of theFormiggini screw (Fig. 83), creating the double-he-lix implant (45); a similar device, with minor mod-ifications, was also employed by his countrymanMax Jeanneret (Fig. 84).The greatest developments in endosseous implan-tology took place in the 1970s with the creation ofthe “blade” (the name used by Linkow) (46) and the“needle” (the name used by Scialom) tantalum im-plants (47–48). In Italy, several authors proposed anumber of modifications, such as the “custom uni-versal blades” created by Muratori in 1970 (49) andthe “postless polymorphic blade implants” devisedby Ugo Pasqualini; (46) in 1975 Pier Luigi Mondanicame up with the idea of using intraoral solderingfor the needles; in 1974 Dino Garbaccio proposedthe bicortical self-threading screw. These authorswill be discussed in the chapters that follow.21

In the late 1970s and early 1980s, Brånemark pre-sented the so-called “osseointegrated” implants. Ac-cording to Brånemark, osseointegration “is the di-rect structural and functional connection betweenliving bone and the surface of a load-bearing im-plant.” The method consists of positioning screw-shaped titanium implants with small threads(screws for metal), offering good resistance to torqueand able to assure good mechanical elasticity. Theyhave microgrooves that permit integration with thebone tissue, which shapes itself around the implant.Titanium is considered the most biocompatible ma-terial, as it can be used in a wet-organic environ-

ment; it is made of titanium dioxide (51). Many of these concepts had already been anticipat-ed by Pasqualini (1962), as we will detail in thesechapters (50, 52).

References

1. ZAMPETTI P. Storia dell’implantologia. Proceeding of the1st National Congress of Multidisciplinary Implantology. Isti-tuto Padre Monti: Saronno, Italy; 2004. p. 135. 2. ALDOVRANDI C. A Odontologia na America Precolom-biana. Rev Ass Patil Chir Dent 1949;1:25.3. ANDREWS R.R. Prehistoric crania from Central America.Int Dent J 1893;12:914.4. BOBBIO A. The first endoosseous alloplastic implants inthe history of man. Bulletin of the history of Dentistry1972;6:20.5. ZAMPETTI P. Primi tentativi di implantologia orale oste-ointegrata in epoca precolombiana. Doctor Os 2005Ott;16(8):979-80.6. BOBBIO A. Maya, the first authentic alloplastic, endosse-ous dental implant. A refinement of a priority. Rev Assoc PaulCir Dent 1973 Jan-Feb;27(1):27-36. 7. BOBBIO A. Historia de odontologia. Dispense della Facol-tà di Odontologia di Araquara; S. Paulo. 1969. 8. CACERES E. Historia de odontologia en Guatemala. Cittàde Guat: Tipografia Nacional de Guatemala; 1938.9. PASQUALINI M.E. Un impianto alloplastico in una man-dibola di 1300 anni. Ricerca istologica. Dent Cadmos2000;11:57-62.10. ZAMPETTI P. Luci ed ombre in implantologia. Procee-dings of the 17th International Odontostomatologic Con-gress; Monte Carlo, Principality of Monaco. 2005. p. 23. 11. RODRIGUEZ BAENA R., RIZZO S., ZAMPETTI P. Con-siderazioni storico-cliniche sull’evoluzione dell’implantolo-gia. Rivista di Storia della Medicina XII NS 2002;XXXIII(1-2):149-56.12. NUNZIANTE A., BAZZI F. Storia dell’implantologia. Pro-ceedings of the 21st International Congress of History of Me-dicine; Siena, Italy. 1968. p. 874-80.

Fig. 83 Different designs of endosseous screws used in the 1960s and 1970s. The middle one is the Tramonte screw, currentlyproposed as an “elective” immediate load implant. Fig. 84 The Jeanneret implant.

21 It must be remembered the Swiss Samy Sandhaus who, towards theend of the 1960s studied the one-step and two-step screws inalumina and zirconia called “Cristalline Bone Screw”.

83 84

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13. CASOTTI L. Odontology in the museums. Minerva Sto-mat 1955 Mar-Apr;4(2):122.14. GUERINI V. Storia dell’odontoiatria. Torino. 1976.15. ZAMPETTI P. Due dentisti-artisti del Settecento francese:Louis Fleury Lecluse e Francois Joseph Talma. Doctor Os2004 Set;15(7):809-10.16. CALLISEN E. Principi del sistema della chirurgia moder-na. V. 1-2, 4-6. Bologna. 1796-1799. 17. MURATORI G. Curiosità e fatti nell’evoluzione degli im-pianti e dei trapianti dentari. Proceedings of the 24th Natio-nal Congress of History of Medicine; Taranto-Bari, Italy.1969.18. ZAMPETTI P. L’evoluzione dei materiali utilizzati in im-plantologia. Considerazioni storico-cliniche. Odontoiatria.Rivista degli Amici di Brugg 2003;22(1):65-72. 19. AULIZIO F. Cenni storici sull’evoluzione della protesidentaria. Riv Ital Stomatol 1960:497-520.20. In honor of Giuseppangelo Fonzi, inventor and maker ofthe 1st porcelain teeth in 1806. Dent Cadmos 1968Aug;36(8):1185-86.21. MAGGIOLO G. Manuel de l’Art du Dentiste. Nancy: Edi-tions C. Leseure; 1809.22. BERTOLINI A.M., MALIZIA E. Gli elettroliti in biologia ein medicina. Milano: Editrice Ambrosiana; 1951.23. MURATORI G. L’implantologia attraverso i tempi fino aiconcetti più moderni. Dent Cadmos 1993:13-40.24. GREENFIELD E.J. Una radice artificiale. Lab Progr DentRev 1911;XV.25. GREENFIELD E.J. Implantation of artificial crown andbridge abutments. Dent Cadmos 1913;55:364.26. DAHL G.S.A. Subperiostal implants and superplants.Dental Abstracts 1957;2:685.27. STROCK A.E. Experimental work on a method for repla-cement of missing teeth by the direct implantation of a me-tal support into the alveolus. Am J Orthod Oral Surg1939;25:467.28. STROCK A.E, STROCK M.S. Method of reinforcing pul-pless anterior teeth-preliminary report. J Oral Surg1943;I(6):252-255.29. STROCK A.E., STROCK M.S. Further studies on the im-plantion of inert metals for tooth replacement. Alpha Omega1949;43:107-10.30. LEHMANS J. Implants à arceaux endo-osseux. RevueOdonto-stomatologique 1961.31. GERSHKOFF A., GOLDBERG N.I. Implant dentures.Philadelphie: JB Lippincott Co; 1957.32. CORTESE G., LINKOW L.I. Survival of a subperiostealtantalium mesh from 1955 to 2004, still in situ and well per-forming in 2004. Historical report. Br J Oral Maxillofac Surg2005;44(1):71.33. FORMIGGINI M.S. Protesi dentaria a mezzo di infibula-zione diretta endoalveolare. Riv Ital Stomatol 1947:193-199.34. FORMIGGINI M.S. Otto anni di pratica col mio metododi infibulazione metallica endomascellare. Riv Ital Stomatol1955:38-44.

35. FORMIGGINI M.S. Protesi fisse in bocche edentule amezzo di infibulazioni dirette endomascellari. Riv Ital Stoma-tol 1954:814-821. 36. FORMIGGINI M.S. Impianti alloplastici endossei. Precisa-zioni sul mio metodo. Rass Trimest Odontoiatr 1956:94-100.37. PERRON ANDRèS C. Biodinamica degli impianti endos-sei a spirale. Dent Cadmos 1963:9.38. MARZIANI L. L’uso del tantalio nella chirurgia ricostrut-tiva con speciale riguardo all’impianto dentale subperiosteo.Proceedings of the 11th International FDI Congress; Lon-don.1952.39. BRANCHINI C. Rilievi istologici su un impianto allopla-stico umano. Proceedings of the 2nd International Sympo-sium on Alloplastic Implants; Naples, Italy. 1958. p. 263-76.40. PALAZZI S. Stato attuale della dottrina degli impianti se-condo l’esperienza della Clinica Odontoiatrica dell’Universi-tà di Pavia. Rass Trimest Odontoiatr 1958:7-9. 41. ZEROSI C. E COLL. Impianto completo sperimentale sucane e controlli istopatologici. Rass Trimest Odontoiatr1956:50-89.42. FLOHR W. Implantation of resin in the region of the pa-ce and maxilla; clinical and histological results. Revue Stoma-tol 1953 Feb-Mar;54(2-3):113-29.43. TRAMONTE S.M. A proposito di una modificazione stru-mentale negli impianti endossei. Rass Trimest Odontoiatr1963:129-136.44. MURATORI G. Metodo personale di impianti endoosseia barra di fissazione rimovibile. Minerva Stomatol 1965:95-102.45. CHERCHÈVE R. Sistema personale di impianti endoos-sei. Riv Ital Stomatol 1961:388-400.46. Linkow L.I. 8 years of intraosseous implantations. DentCadmos 1970 Dec;38(12):1829-90.47. SCIALOM J. A new look at implants: a fortunate disco-very: needle implants. L’Information Dentaire 1962;44:737.48. SCIALOM J. Implants aiguilles. J Oral Implant TransplantSurg 1965;11.49. Muratori G. Implantation using custom-made blades.Dent Cadmos 1971;39(6):897-91650. PASQUALINI U. Reperti anatomo-patologici e deduzioniclinico-chirurgiche di 91 impianti alloplastici in 28 animalida esperimento. Riv Ital Stomatol 1963:3-98.51. FAVERO G.A. Osteointegrazione clinica: i principi di Brå-nemark. Milano: Masson; 1994.52. PASQUALINI M.E. L’osteointegrazione ha origini italiane?Proceedings of the 9th SISOS National Congress; Saronno,Italy. 2006. p. 20-21.

Figs. 6–9 Courtesy of Prof. Amedeo Bobbio – São Paulo, Brazil.Fig. 37 Courtesy of Prof. Leonard Linkow – New York, United States.Figs. 48–50 Courtesy of Prof. Alvin Strock – Boston, United States.Figs. 55–71 Courtesy of Dr. Giancarlo Cortese – Turin, Italy.Figs. 1–4, 7, 9–11, 16, 22, 23 taken from Pasqualini M.E. “Un impiantoalloplastico in una mandibola di 1300 anni. Ricerca istologica.” DentCadmos 2000;11:57–62.


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TREATISE OF IMPLANT DENTISTRY CHAPTER II

The first chapter introduced the reader to the implantdentistry of the past when, despite the enthusiasm ofthe few who had successfully placed implants in hu-mans, the reasons for the vast number of failures wereunclear. At the time, few authors had presented theirpersonal inventions, generally tending to attributefailure to others’ methods and success to their own! Furthermore, many orthodox thinkers rejected theidea of implants, speculating that the absence of theepithelial attachment—a widespread but wrong con-cept—would inevitably lead to implant expulsion.They failed to realize that many traditional prosthe-ses anchored to natural teeth, and thus unquestion-ably with the attachment lacking in implants, under-went the same fate.At the AMDI Congress (Italian Dental Association)held in Stresa in 1952, Formiggini presented the caseof a patient wearing a dental prosthesis fixed one ofhis spiral implants, with no evidence of drawbacks.His “reckless” intervention drew criticism over theabsence of a seal between the outside and the insideof the body. This objection, based on mainstream sci-ence, discredited previous implants as well asFormiggini’s, although they appeared to be incrediblystable and showed no sign of tissue damage.It must be acknowledged that, based on reports of thefirst implant attempts performed by Maggiolo, whoproposed the first one, and those by other authorswho presented their own over the 150 years that fol-lowed, it was virtually impossible to tell if success orfailure was due to the materials or, rather, if the causelay in different surgical techniques, individual reac-tivity or the operator’s technical skills. A specific con-cern had to be added to the many open questions:permanent communication with the external envi-ronment, which could favor the penetration ofpathogens into the body. The effect exerted by oc-clusal load, both in the immediate postoperative pe-riod and over time, likewise remained unsolved.

In an endeavor to shed light on the topic UgoPasqualini proposed a series of progressive studiesdealing with a single issue at a time, moving to thefollowing only after finding clear, acceptable and ob-jective answers for each one.This chapter will be devoted to these studies con-ducted long ago. In order to understand their advan-tages and limitations, the reader should be aware thatscientific demonstration of the protective principle ofreparative osteogenesis (i.e. osseointegration)—nowwrongfully attributed to Brånemark’s later research—originated in those very studies. The delayed and im-mediate load implant techniques will be discussedextensively in this book, together with indications fortheir potential use.

M.E. Pasqualini

The four issues addressed byresearch on endosseous implants

I began this research in 1957 and published theresults at the end of 1962. It was conducted on28 dogs, for a total of 91 endosseous implants,with the cooperation of three university insti-tutes: the Dental Institute of the University ofModena, the Pathology and Special VeterinarySurgery Institute of the University of Milan, andthe Institute of Pathological Anatomy of the Uni-versity of Modena. The study took five years andthe issues I planned to address were:1) clinical, radiographic and histopathological as-

sessment of the biocompatibility of the mostwidely used materials;

2) parallel assessment of the osseointegrativeproperties of endosseous artifacts by means of

ANIMAL TESTING

by Ugo Pasqualini

43

reparative processes of surgical wounds;3) clinical, radiographic and histopathological

evaluation of how permanent communicationwith the external environment, an essentialcondition for implant loading, influences adja-cent mucosae and tissues;

4) assessment of the effect of occlusal load sec-ondary to prosthesis placement (Fig. 1).

Despite any misgivings, I choose dogs as my testanimals, as they are close enough to humans interms of diet and general physiology. At first I used a monkey, which has a masticatoryapparatus similar to that of humans, although itlacks Bennett movement. An initial attempt con-vinced me of the tremendous difficulties that thischoice would entail in the future. Monkeys arenot easy to approach and after surgery they try—with tenacious constancy—to modify any im-

plants that are placed. They suffer a great deal incaptivity, do not tolerate anesthetics well, andhave different feeding needs than humans. Theiroral cavity is also much smaller than that of dogs. Therefore, I chose healthy dogs examined at theInstitute of Veterinary Surgery of the University ofMilan.1 Their partial edentulation was performedunder general anesthesia (with chemital sodiumIV at the dose of 4 mg/kg, after preanesthesia withEucodal vials 0.01 mg IM, at the dose of 1 or 2vials, weight-adjusted). Only the premolars and tearing teeth of themandible were extracted, leaving the front teethfrom canine to canine and all the upper teeth insitu (Figs. 2, 3). Despite the loss of premolars andthe lower tearing teeth, the animals were still ableto eat as they were given a special diet, whichconsisted of boiled rice with oil, ground meat and

Animal testing II

?

??

?

?

?

??

1. Alloplastic materials and reactions of the connective tissue

2. Retentive structures of the alloplastic root

3. Neck area and reactions of the epithelium to the alloplastic material

4. Masticatory load

Fig. 1 The four phases of implant research (U. Pasqualini,1962).

Fig. 3 The dogs could eat due to the presence of the lowerfront teeth and the entire upper dentition.

Fig. 2 The teeth extracted from the animals: two premolarsand two tearing teeth.

1 I would like to thank the Pathology Institute of the Veterinary Clinic of the University of Milan, Aldo Tagliavini, who was its director at the time,Armando Santi and Antonio De Gresti; I am also grateful to Tarciso Micheletto and Alberto Cupia for their kind, selfless and very valuableassistance.

1

2

3

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cooked vegetables. All animals regained and ex-ceeded their initial weight. Extractions were al-ways followed by suturing of the surgicalwounds, which accelerated the healing processand favored socket ossification.Three to four months later, the animals under-went another surgical procedure (in this case, al-so with preanesthesia with Eucodal IM followedby general anesthesia with chemital sodium) inorder to proceed to the next experimental phase. A total of 91 implants were placed. For mandibleexplants, 28 of the 30 animals initially implantedwere sacrificed; two of the dogs were killed by ex-cess anesthesia during the extraction procedures.

Study on biocompatibility of the materials

Choice of materialsI expected the first phase of my research to yielda conclusive answer about the biocompatibility ofimplant materials with regard to the type of tissuereaction at the insertion sites, where they hadbeen in a quiescent state for six months below themucosa (Fig. 4). Implant materials had to be:1) biologically inert for the host tissues;2) physically and chemically stable over time,

without any alterations;3) resist to fracture, wear and deformations;4) sterilizable.Venable, Stuck, Beach and Key (1937–47) (1–3)had already demonstrated that implant materialshad to be chemically and electrolytically inert, be-cause potential differences can also occur be-

tween implant and host tissue due to the presenceof organic fluids, which act as electrolytes. Thegalvanic currents generated as a result could haveled to metal corrosion and subsequent implantexpulsion. Bertolini and Malizia (4) also conduct-ed an exhaustive study on electrolytes in biologyand medicine, a research so interesting that, eventoday, it is a very useful reference for those inter-ested in probing the topic. The following materials had already been usedbefore my experimentation, with mixed results:1) gold and gold alloys;2) platinum and other elements from the same

group of Mendeleev’s periodic table;3) silver;4) copper, lead and manganese;5) porcelain and glass; 6) plastics; 7) tantalum; 8) stainless steel and Stellite (chromium-cobalt-

molybdenum).Silver, copper, lead and manganese were exclud-ed from the trial. In effect, silver is soluble in allcommon acids and also oxidizes in the presenceof atmospheric oxygen, forming silver sulfate,which is poisonous. Copper also lacks the funda-mental qualities required for implant materials,because it readily alters in the presence of humid-ity, forming cupric carbonate (verdigris), which isalso poisonous. As already mentioned, lead like-wise lacks the properties required for implant ma-terials. Pure 24K gold does not have adequate resistanceto load, wear and deformation. These negative as-pects seemed to be offset by the addition of oth-er noble metals from the platinum group: palladi-um, iridium, rhodium or osmium, in alloys al-ready employed by other investigators. I decidedto include them in my study, as I was unable tofind any histological reports about tissue reac-tions to these materials. The fact that the authorswho used them and guaranteed (as usual!) theconstantly positive results of their procedures wassimply not enough for me.As to the behavior of tissues in direct contact withporcelain, again, I could not find any histologicalreferences. Although high-fusing porcelain hadno fracture resistance, the literature reportedgood clinical performance if it was reinforcedwith internal metal structures. A porcelain with alow fusion point, whose strength was increasedwhen fired on a special gold alloy, had recentlybeen put on the market, so I felt it was appropri-ate to separately examine the behavior of thisporcelain and the possible biocompatibility of its

1 2 3 4 5 6 7 8

1. Self-hardening resin2. Self-curing resin3. High-fusing porcelain4. Gold-platinum5. Platinum-iridium6. Ceramco gold and Permadent7. Stellites (Vitallium)8. Stelliti (vitallium)

Fig. 4 The biocompatibility tests were performed with differentmaterials prepared with a truncated cone shape, and inserted below themucosa with the same surgical technique (U. Pasqualini, 1962).

{{

{

Materiali alloplastici e reazioni del connettivo

4

45

alloy support, known at the time as Ceramcogold, which had a secret formula.2

Tantalum, whose complete biocompatibility hadalready been demonstrated in laminar forms,proved to be so difficult to cast that it had to beexcluded from the study for use in endosseousimplantology. Scialom’s drawn-tantalum needletechnique, which will be examined later in thebook, was still unknown at the time (6). Severalinteresting histological studies had already beenconducted on self-curing and thermosettingresins, but the results were so conflicting that Ifelt it appropriate to include them in my experi-mental program.Vitallium, already employed in orthopedics, wascertainly biocompatible. Until then it had beenused by only a handful of authors in endosseousimplantology, but I decided to include it never-theless, in order to obtain additional direct con-firmation of its biocompatibility.

Research methodsAll implants had to be buried in the bone tissuebelow the mucosa for approximately six months(Fig. 5).The examined materials were: 1) self-curing and thermosetting resins;3

2) low-fusing porcelain;3) 5% gold platinum alloy;4) platinum-iridium;5) Ceramco porcelain and gold alloy;6) surgical Vitallium.Each material was shaped into a truncated cone,and all implants were placed with the same sur-gical technique (Fig. 6).The artifacts, identical in shape but different incomposition, were inserted in open surgery intocavities, prepared by calibrated drills, onto thehealed edentulous ridges. The implants wereburied in the bone tissue up to its external sur-face, and were immediately covered by suture ofthe mucosa to avoid microbial contamination andmechanical stress. The implant sites were prepared with two conicaldrills of progressive diameter. The first drill wasused to create a small cavity, which was expand-

ed to the desired diameter with a larger one.Drilling was always performed under saline irri-gation to prevent overheating and bone necrosis. To avoid result bias due to individual reactions, atleast five different materials were placed in eachmandible of the first animals, and all insertionswere meticulously followed by suture of the mu-cosa (Figs. 7–10).By adopting these precautions, I intended toavoid the controversial conclusions of previousstudies, often conducted with unclear techniquesand dissimilar artifacts, and communicating withthe external environment.4

Animal testing II

Fig. 5 Overview of the 28 experimental inclusions used fortests on tolerance to different metals and materials (1956).

Fig. 6 The surgical technique employed for insertion.

2 Other types gold alloys fused to porcelain were marketed later, but I believe that they are not biocompatible,as we will see was the case with Ceramco-gold.

3 Several truncated cone implants were prepared, four made of thermosetting resin and four of self-hardening resin. Those made of self-hardeningresin in a liquid state were excluded from the experiment because the heat they would have developed during polymerization within the bone wouldhave been cytotoxic and necrotizing.

4 Except for Maggiolo’s gold implant (1809), the silver one by R. E. Payne (1900), Greenfield’s platinum and gold-iridium type (1913), the Vitallium oneby the Strock brothers (1948) and Benaim’s resin implant (1959) (7–13).

5

6

46


Furthermore, while the experimentation on hu-mans performed by most of my predecessors hadbeen limited to the observation of general clinicaltolerance, supported only by radiographic testsand very few biopsies (most examinations wereperformed in the event of expulsion), my researchwould have to include autoptic and histopatho-logical examinations for definitive acceptance orexclusion of the materials being tested.There were twenty-eight inclusions, four for eachtype of material: truncated cones made of ther-mosetting resin, self-hardening resin, porcelain-gold, platinum gold, platinum-iridium, Ceramcoporcelain and gold, and surgical Vitallium.

ResultsAfter one year (it took six months for the edentulousareas to heal, and six more months for completionof the tissue reactions around the inclusions) I ob-tained reliable answers for each examined material.

The dried mandibles were radiographed beforeexamining the inclusions, which immediately re-vealed different macroscopic tissue reactions tothe various materials. I will not describe themhere, because interested readers can find detailedreports in the captions of the corresponding fig-ures (Figs. 11–17). The histological examinations required removalof the inclusions and serial sections of the adja-cent tissues (Figs. 18–25).All tissues adjacent to low-fusing porcelainsshowed atypical foamy degeneration. The reportof the bioptic analysis of the bony tissue apposedon the porcelain surfaces, performed by AntonioStagliani, Director of the Anatomopathology In-stitute of the University of Modena, made the fol-lowing observations.

A superficial examination reveals that tissue responseto porcelains appears to be positive in terms of the

Fig. 7 Five different materials inserted in a hemimandible. Fig. 8 Other inclusions inserted in sockets prior suture of the mucosa.Fig. 9 Suture of the mucosa. Fig. 10 Healing of the soft tissues six months following surgery.

Fig. 11 Mandible explanted six months following surgery, prior to visualization of the implants. Fig. 12 Implants six months followingsurgery, after incision and detachment of the mucosa. Fig. 13 X-ray of two hemimandibles from the same animal: a) left to right:

thermosetting resin, Vitallium, self-curing resin (expelled), porcelain, gold alloy for porcelain; b) left to right: Vitallium, self-hardening resins(expelled), Vitallium, porcelain. Fig. 14 Left to right: porcelain, self-curing resin, three Vitallium implants.

Fig. 15 Left to right: platinum gold and platinum-iridium implants (expelled). Fig. 16 X-ray of Vitallium implants. Note the bone levelabove the shorter implant. Fig. 17 Detail of the formation of new bone above the Vitallium implant (arrow).

a b

7 8 9 10

11 12 13

14 15 16 17

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absence of inflammatory phenomena, but the bonetissue is only partially visible, with bone cells that arenot very evident, included in small niches. The cyto-plasm is negligible; the nucleus is small and almostpycnotic, with compact chromatin. In some sectionsthe lamellar bone structure is completely absent:Here the tissue has been transformed into an amor-phous acidophilic mass with no detectable cellular

elements, and it seems to show the dissolution of thefundamental bone structure, following breakdown ofits osteocytic component5 (Figs. 26–28).

The Ceramco gold artifacts were clearly in an ex-pulsive phase, which had already been foreshad-owed by the radiographic examinations. Thehigher histological sections showed an invaginat-

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Fig. 26 Radiographic appearance of a porcelain inclusion (arrow) next to the outcome of a self-curing resin implant expulsion (left)and the inclusion, in an expulsive phase, of a Ceramco gold implant (right).

Fig. 27 Foamy degeneration of the bone tissue adjacent to the porcelain. Fig. 28 Histological finding of tissue adhering to a porcelain inclusion; the collagen fiber layer is visible above.

5 From the original publication of U. Pasqualini Reperti anatomopatologici e deduzioni clinico chirurgiche di 91 impianti alloplastici in 28 animali daesperimento. Riv It Stom 1962;12:36 and 1963;1.

Fig. 18 Radiographic overview of the analyzed materials. Fig. 19 Radiographic detail of the threeperfectly osseointegrated Vitallium implants. Fig. 20 Hemimandible with five inclusions in situ, afterdecortication. Fig. 21 Anatomical specimen immediately after removal of the inclusions, followingimmersion in formalin and prepared for the histological examination. Fig. 22 Macroscopic appearance ofthe anatomical specimen of a mandible; a gold platinum implant can be observed on the left and a Vitalliumimplant on the right. Fig. 23 Diagram illustrating the technique used for histological sections.Fig. 24 A few of the many histological specimens. Fig. 25 Macroscopic appearance of a histologicalsection: a) compact bone and b) cancellous bone.

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ed and atrophic epithelium over large areas of fi-brotic tissue, irregularly scattered among en-closed areas of bone tissue in hyaline-like degen-eration. The sections performed at the apical tis-sue resorption level, easily visible on the X-ray,showed the invasion of small inflammatory cellsthat completely replaced the original bone tissue. Around the thermosetting resin cones, all still inplace, there was a soft and easily detachable fi-brous capsule that was very evident in the histo-logical specimens, which in the deepest layerwere composed of massively hyaline-like tissuesurrounded by granulation tissue. All the truncat-ed cones made of self-curing resin were absentand had already been expelled (Figs. 29–31).Around the gold-platinum and platinum-iridiumalloys, I found signs of bone involvement, with athin layer of collagen fibers interposed betweenthem and the surface of the metals extracted forthe histological examination (Fig. 32), as well aspatterns of similar involvement with a layer of

variable thickness, depending on the sectionedarea, and irregular fibrotic tissue.The Vitallium inclusions instead appeared to beperfectly osseointegrated due to physiologicalreparative osteogenesis of the surgical insertionsites, with the progressive apposition of young,healthy and well-remineralized bone tissue, withno interposition of collagen fibers between thenew bone and the metal. The more intense coloration of the peripherallamellae on the outer surface of each artifact (a se-mi-arc section is all that is visible in the figure) isdue to greater activity by mucopolysaccharides,which are abundant in newly formed tissues andthus permit greater stain uptake. It was very in-teresting to note the different architecture, con-stantly devoid of any inflammation, of both theold and new bone tissue, which was alwaysarranged in well-oriented concentric lamellae onthe outer surface of the Vitallium cones (Figs. 19,33, 34).

ConclusionsThe study confirmed that the failures of manyprevious implant attempts were attributable tothe use of unsuitable materials, showing that in-clusions made of biocompatible substances, with-out communication with the external environ-ment, underwent complete osseointegration.Having verified that surgical Vitallium, a chromi-um-cobalt-molybdenum alloy with no traces ofberyllium, was a material that, per se, would notlead to failure, the other materials were excludedfrom the second study, as they proved to be toxicto the body. I gave up any further implant at-tempts with resins—self-curing and thermoset-ting alike—since my research confirmed their bi-ological inadequacy, nor did I conduct any othertests with noble alloys such as platinum-iridium

Fig. 29 The different radiographic aspect of the outcome of self-curing resin that was expelled (arrow) between a porcelain inclusion (right)and a Vitallium inclusion (left). Fig. 30 Thermosetting implant showing marked peripheral radiolucency, indicating expulsion.

Fig. 31 Histological specimen of the tissues adjacent to a thermosetting resin. Tissue disarrangement, hemorrhagic areas and hyalinedegeneration are evident.

Fig. 32 Histological appearance of the tissue enclosing aplatinum-iridium gold alloy, with pattern of tissue damage andbone resorption.

29 30 31

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and gold-platinum, which were equally cytotox-ic, or with porcelain.It was very interesting to prove histologically thatporcelains (which many years later would be pre-sented again as the ideal material) had indeedcaused the peculiar foamy degeneration de-scribed by Stigliani, which completely altered thehistological appearance of the including bone. Itis important to note that a postoperative X-ray sixmonths later showed that these porcelainsseemed to be fully osseointegrated by healthy tis-sue that, instead, “foamed” around them. The ra-diographic picture of the apparent compenetra-tion of bone tissue and porcelains was due to thesimilar radiolucency of porcelain and the con-tiguous bone. Histological analyses are thereforeof crucial importance in such cases, when the re-sults clearly contrast with the outcomes thatcould be inferred from the X-rays.

The retention of endosseousinclusions

IntroductionAfter the aforementioned results, I decided to de-sign a retentive form that would allow Vitalliumto be used as s stable abutment that could bear afuture prosthetic load. Here I have quoted my introduction to the report(1962) of the subsequent trial, so that the readercan compare my deductions on Vitallium withconsiderations about titanium, which is currentlyemployed for dental implants.

The roots of human teeth are connected to the boneby means of a joint, unique in the entire organism,known as the gomphosis. Due to its presence, thetooth is not in direct contact with the maxillary bone,but is joined by means of a very large number of col-lagen fibers (Sharpey’s fibers) that connect the radic-ular cement to the lamina dura of the socket walls.They provide stability but also have a very light cush-ioning effect. Sharpey’s fibers thus act as an in-traosseous ligament between the socket walls and theradicular cement, which are very similar to each oth-er from a histological point of view.The hopeful attempt to recreate this type of connec-tion with replantations never yielded appreciable re-sults because, after its complete destruction duringextraction, the osteofibrous joint is replaced througha process of ankylosis. Regarding implants, my previous study demonstrat-ed that the bone forms in a mirror-like fashion on the

surface of biocompatible materials (Vitallium) thatremain buried during the reparative osteogenicphase. Unfortunately, however, this does not allowme to assert that mere direct contact of the bone tis-sue with the macroscopically smooth surfaces of theinclusions is sufficient for their fixation.The Vitallium cones employed for the biocompatibil-ity test had real contact with the new bone, withoutthe juxtaposition of collagen fibers and with remark-able adhesion, although it was not so strong that itprevented me from extracting them for the histolog-ical analysis of their including tissues. In light of the current knowledge [the reader shouldbear in mind that we are talking about 1962!], itseems that implant stability is achievable onlythrough bone proliferation between the macroscopicretentions on the inner or outer surface of theirburied portion. Implants should also be kept in aquiescent state for the whole period required fortheir fixation.

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Fig. 33 The healthy appearance of the bone tissue next toVitallium. Note the concentric stratifications of the newly formedarea, mirroring the metal implant surface.Fig. 34 Close-up of the previous image at a highermagnification. Note the absence of collagen fibers and the moreintense staining of the new tissue, which—like all young tissue—has plenty of mucopolysaccharides with a high affinity forlaboratory staining (hematoxylin-eosin).

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Thirty-five years later I was forced to revise thoseconsiderations. Like other colleagues, I had thechance to verify that it was impossible to removeseveral endosseous needles that had fractured af-ter years of service. Their outer surface was ap-parently smooth, but even if firmly grasped withforceps they were impossible to remove from thebone, to which they seemed to have “fused.” Wewill have the chance to examine this fascinatingtopic and update it with very recent informationin Chapter 10. Now, however, I will return to myconsiderations from 1962.

I had also noted that the temporary retention of en-dosseous implants, which my predecessors immedi-ately provided with an external abutment, almost al-ways occurred with the interposition of a thick lay-er of fibrous tissue: the ratio between its thicknessand that of the newly formed outermost bone repre-sented the various phases of the “stable mobility”typical of most of the implants of the time (thoughnot all) (14–19). According to many authors of theera, the faster the connection of the external abut-ment with stable natural dental elements wasachieved, the thicker the bone layer became, thusaugmenting implant stability. Consequently, theyrecommended inserting the submerged implant sec-tion as deeply into the bone tissue as possible, sincethis would further increase the ratio between thenew bone and the layer of interposed fibrous tissue,which is much less retentive. Since in my previousstudy I had verified that bone apposition on myburied Vitallium inclusions took place without theinterposition of fibrous tissue, I planned to design aretentive form that would avoid any load stress bythe external abutments, in both the postoperativeand osseointegrative phases, as this could affect theosseointegration process. This was the only way toget an objective answer about the possibility that thebone tissue could definitively incarcerate my ventedinclusions of biocompatible material in a stable andpermanent manner.

Study on the best retentive design for the inclusionsResearch into the best design for retentive inclu-sions, in terms of minimal bone destruction, keptme from concluding the second phase of thestudy. I had already published a diagram with thefollowing solutions to create the insertion site on

the edentulous ridge; the vented artifacts had tobe included by means of the osteogenic reparativeprocesses of the surgical incisions:a) sagittal groove;b) cross groove;c) Greenfield’s circular groove;d) full-thickness bore (Fig. 35).I had tried and immediately abandoned the sagit-tal incision of the alveolar ridge, conceptuallysimilar to the one later employed by Linkow.6

High-speed drills had not been invented yet andI faced numerous difficulties in attempting to cre-ate a regular groove. The straight incision, alreadyproposed by Lehmans for his arch implant(1946), classified in my diagram as a sagittalgroove, supposedly meant reduced tissue sacri-fice, but only in theory: since I had to use low-speed drills my groove ended up being impreciseand much larger than necessary. I faced the samedifficulties with the cross groove, which merely

Fig. 35 Different implant techniques designed and sketchedby Pasqualini, published in 1962.The author also anticipatedthe technique for blade implants (letter A in the diagram), takenup by Linkow and published eight years later.

6 Leonard Linkow republished my sketch, acknowledging my authorship, on pages 90 and 92 of Theories and Techniques of Oral Implantology,published by C.V. Mosby Company, which he wrote two years later with Raphael Cherchève (1970) (20).

35

doubled the problems I had already had with thesagittal one.Using the two drills with progressive diametersused to insert solid cones during the experimenton the biocompatibility of materials, I could eas-ily have created similar cavities in which to insertthe vented—not solid—Vitallium artifacts shapedlike truncated cones, similar to those proposedinitially proposed by Greenfield (Figs. 36–38).I felt that his second proposal of a circular bonegroove was the one that would permit the inser-tion of vented cylinders very similar to those hehad designed in 1913, the difference being theuse of a material such as Vitallium, whose com-plete biocompatibility I had just proved histolog-ically.Unlike completely empty cavities, Greenfield’scircular groove left a core of vital bone in the im-plant site. This would theoretically reduce thetime needed for cylinder integration, since thereparative osteogenesis of the small surgical open-ing would be extinguished after bone growththrough the venting of the Vitallium cylinder(Fig. 39).

Research methodsIn order to obtain reliable answers, like Green-field I avoided any communication with the ex-ternal environment, protecting the artifacts viaimmediate suture of the mucosa, which I had pre-viously incised and detached to visualize the bonesurface to tackle with the toothed hollow drill.7

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Fig. 36 Original drawing by E.J.Greenfield (from Dent Cad 1913;4364).Fig. 37 Diagram of the various solutions adopted for the emergingpost: (1) deepening of gingival pocket, (2) natural pocket,and (3)pocket according to Greenfield’s and personal methods (U.Pasqualini,1962).Fig. 38 Diagram of an implant with a connection with the externalenvironment, inserted below the mucosa to encourage inclusiveosteogenesis without external stress (1).Representation of thecompleted osteogenesis (2).Connection with the “prostheticabutment”and crown (3 and 4).

Fig. 39 The surgical technique.36

37

38

39

7 I did not feel that Greenfield’s “tissue punch” would be useful here, asit limited the visibility of the underlying bony crest and the choice of theoptimal site, also making it more difficult to perform the protectivesuture of the mucosa.

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The manufacture of the vented Vitallium cylin-ders was not an easy task, since the alloy castingrequired clever expedients and coatings thatcould withstand the extremely high temperaturethat was required: 1350–1450° C. The toothedhollow drill, commissioned from a specializedcompany, was much easier to make (Figs. 40,41).The first infixions were performed in two dogs,placing four cylinders in each hemimandible, fora total of sixteen implants. After creating the circular grooves, before placingthe vented Vitallium cylinders I removed about 2mm of the outer layer from the central bone corewith a round bur, in order to bury the cylindersbelow the occlusal surface of the alveolar ridge(Figs. 42, 43).The inclusions, immediately protected by sutur-ing the mucosa, were left in a quiescent state andwithout communication with the external envi-ronment for the following four months, which Ibelieved was sufficient to complete the reparativeosteogenesis of the surgical grooves and subse-quent integration of the cylinders.The results were not as uniform as I had hoped.In fact, the mandibles of these animals had areaswhere the cylinders were missing, alongside per-fect inclusions (Figs. 44, 45).In those areas I had made the mistake of forcingthe cylinders into the insertion sites with pressureexceeding the metabolic healing capabilities ofthe inner bone core. The sectors where implants had been lost stillshowed signs of their violent postoperative expul-sion. In two animals, checked one month aftersurgery, it was possible to observe two expulsionsin progress.If the first part of my research had not alreadyconfirmed the biocompatibility of the materialused for the baskets, it would have been hard for

Fig. 40 Castings of Vitallium baskets (1956).Fig. 41 Two of the author’s Vitallium cylinders, with the toothed drillsused for their insertion into the circular bone groove (U. Pasqualini,1962).

Fig. 44 Hemimandible with perfect inclusions.Fig. 45 The same hemimandible showing the area (left) inwhich an implant was expelled for unknown reasons (U. Pasqualini, 1962).

Fig. 42 Three cylinders with internal threading, immediatelyafter insertion (U. Pasqualini, 1962).Fig. 43 The three cylinders from the previous illustration,showed in the autoptic specimen at three months from surgery.Note the adhesion of the tissues over them (U. Pasqualini,1961).

40 41 42

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me to avoid making the mistake of ascribingthose failures to the material rather than the sur-gical preparation, or to communication with theexternal environment, which I had consciouslyavoided.There remained doubts as to why, in the same an-imals (and often in the same hemiarch), somecylinders were expelled because they had beenpressed too deeply into the grooves and otherswere instead perfectly integrated (Figs. 46, 47). After a few tests on dried mandibles I realizedthat the diameter of one of the toothed hollowdrills I had commissioned to make the circulargrooves was 2/10 mm smaller than the others.This minor difference is what led to compressionand/or fracture of some of the bone cores andtheir resorption, with the consequent expulsion

of the connected implants. In this case, rather than enhancing the reparativeosteogenesis of the grooves, the central bonecores were expelled by pathological mechanisms,taking the connected implants with them. Therefore, I inserted sixteen vented baskets intwo other edentulated dog mandibles, but thistime I placed them in completely empty cylindri-cal holes after removing the central bone core(Figs. 48–50). All sixteen cylinders were perfectly osseointegrat-ed by means of reparative osteogenesis of themodified cavities (Figs. 44, 51–65).In the mandibles of these two dogs I also insert-ed a vented Vitallium cone, placed directly in ahole made with the same drills used to insert thecones in various materials for the first phase ofthe study. The results described above provided importantinformation, indicating that biocompatibility andisolation from the external environment were notsufficient, per se, to ensure the success of the in-clusions, which could have been expelled by ex-cessive compression of the bone tissue, causingnecrosis and subsequent expulsion by bone re-sorption mechanisms.8

With this data at hand, I could then address thethird issue that I had set out to solve, i.e. com-munication of my inclusions with the externalenvironment, a crucial condition for future load-ing.

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8 In several other chapters, we will again discuss the important topic, examined and discussed here for the first time, of the failures of many otherimplants due to excessive compression of the bone tissue.

Fig. 48 Explanatory diagram of the fracture of the bone core inside a basket, causing bone necrosis and subsequent implant expulsion.Fig. 49 The removed bone core. Fig. 50 Necrotic bone tissue inside the basket (1),due to bone core fracture. Fibrous tissue can be noted

in the peri-implant area (2), indicating failure and thus expulsion.

Fig. 46 X-ray showing the loss of a basket. The arrowindicates the expulsion site.Fig. 47 X-ray of the area where the basket was lost.

46 47

48 49 50

Communication with the externalenvironment

Communication with the external environment, in-dispensable for implant loading (Fig. 66), was thechief question about which everyone at the time—me included—kept their opinions to themselves.The absence of the epithelial attachment, uponwhich Gottlieb had based his theory of the impor-tance of the continuity of the epithelium (21, 22),

drastically reduced the hopes of succeeding inmaintaining constant external communication ofthe abutments, which had to connect the sub-merged part of the implants to the prostheses. Despite the fact that, at the time, communicationwith the external environment was considered thefatal reason for the failure of every type of implant,no one had yet sufficiently demonstrated the pointto which this critical factor could be mistaken withother causes of rejection.

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Fig. 51 X-ray of three vented baskets six months following surgery. Fig. 52 Detail at a higher magnification.Fig. 53 Macroscopic appearance of a basket implant. Fig. 54 Autoptic finding with macroscopic visualization of an osseointegrated

cylinder. Fig. 55 Radiographic image showing inclusion of the implant within the supporting bone tissue.Figs. 56-60 Behavior of the bone tissue surrounding the baskets. Fig. 61 Diagram of the use of the carborundum disk to divide the

experimental implants and the bone tissue in two mirror-image portions. Figs. 62-64 The completed sections.Fig. 65 Histological specimen of bone tissue adjacent to an osseointegrated cylinder. On the right, note the more intense staining of the

including healthy new bone (hematoxylin-eosin, 40X).

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62 63 64 65

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The Strock brothers partially contributed to thisdiscussion with their histological demonstration ofthe absence of inflammatory reactions in caninegums, crossed by an orthopedic screw inserted inthe maxillary bone, as did Formiggini with an in-complete radiographic demonstration on the clini-cal validity of his first stainless-steel spiral infibula-

tions. However, their reports were limited to a fewcases, considered among seemingly analogous onesthat had negative outcomes. Unlike my predecessors, I had the chance to designa much more extensive study, focusing exclusivelyon the risk of permanent communication with theexternal environment: I had at my disposal an ex-perimentally proven surgical technique and a mate-rial like Vitallium, whose biocompatibility and in-tegrating capabilities I had ascertained. The latteroccurred through the reparative osteogenic mecha-nism of the surgical wound, in which the Vitalliumhad been inserted and provided with undercuts orother retentive forms. The important thing was tokeep it in a quiescent state and with no communi-cation with the external environment.Therefore, I simply had to give my Vitallium cylin-ders—placed in the insertion sites without com-pression—structural elements that could connectthem to a future prosthetic abutment, as I wasaware that any failure would be attributed to themalone. To obtain precise answers that could not bemistaken for concomitant causes of failure, I had tomake sure that the connections could not be dis-placed by stress due to occlusal dynamics, whichcould have altered the quiescent state required forthe reparative osteogenesis of the inserting sites(Fig. 67).

Research methodsIt was quite difficult to manufacture the threadingon the occlusal surface of the wax cylinders, but mydental technician was able to forge and replicate itin the subsequent Vitallium castings.9 The newthreaded cylinders were inserted in the same fash-ion as those used in the previous study, followingremoval of the central bone cores within the circu-lar grooves. Three months following the insertions,and again under general anesthesia, I incised againthe mucosa of the dogs to free the threading andconnect it to the respective external posts. I ran in-to a number of difficulties, however, because near-ly all of the threadings were covered by periosteumand, consequently, I also had to destroy sections ofhealthy contiguous tissue. The autoptic microscop-ic sections and histological specimens demonstrat-ed that the addition of the internal threading hadnot modified any of the normal histological archi-tecture of the integrating tissue, which was com-posed of healthy bone harmonically apposed to themetal structures of the cylinders and connected viathe vent holes to the newly formed tissue inside the

Animal testing II

EPITHELIAL A

TTACHMENT EPITHELIAL ATTACHMENT

? ?

Fig. 66 Diagram of the “crucial” factor of implant inclusion,represented by the area of the epithelial attachment along theemerging post.

9 Nino Monfrini, whom I thank for his intelligent, generous and enthusiastic cooperation.

Fig. 67 Diagram of cylinders with short external threadedposts to simplify the implant connection with the futureprosthetic crown.

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cylinders, without the interposition of fibrous tissue(Figs. 58, 59).In another group of dogs, I then inserted a secondset of cylinders, already fitted with a very shortemerging post (Figs. 68, 69), in order to check ifimmediate communication, carefully shieldedagainst occlusion and the compressive forces exert-ed by the tongue, could get through the critical pe-riod of the reparative osteogenesis without infec-tious complications. A positive outcome would allow me to avoid thetroublesome search for the previous internal

threading, which would have required reopeningthe mucosa and destroying the new bone sectionscovering their occlusal surfaces.The very short posts were designed to emerge at themucosal level without transmitting external me-chanical stress, while also maintaining an openingbetween the mucosa and the buried portion of theimplant (Fig. 70).In essence, with the exception of the added risk ofmicrobial infiltration, the quiescent state requiredfor the including osteogenic process had been rig-orously protected. With those cylinders, which hadvery short emerging posts, I aimed to give the firstscientific answer to two open questions regardingthe behavior of tissue in contact with the “emerg-ing” implants, providing:1) the histological pattern of the mucosa surround-

ing the metal neck of the implants;2) the histological pattern of the tissues apposed to

the buried structures and communicating withthe external environment.

The animals were sacrificed six months later. Thesections of the superficial mucosa in contact withthe necks of the implants showed histological pat-tern identical to those of the mucosa adjacent to theamelodentinal junction of natural teeth.The sections of the deeper layers also showed pat-terns similar to those of every other histologicalspecimen (known to date)10 of what is referred toas the epithelial attachment of Gottlieb, found atthe bottom of the gingival sulcus of healthy youngindividuals. Observation of even the most superficial sections,in direct contact with the metal posts, alreadyshowed the absence of the keratinic layer, and inthe deepest sections the constant, gradual decreas-ing of the epithelial layers could be noted, down togerminal cells alone, with no infiltration in the un-derlying corium, proving the absence of any sign ofinflammation (Figs. 71–77).The sections performed in the direction of theemerging posts exhibited patterns identical to thoseof similar sections of the mucosa adjacent to thecervical margin of sound human teeth set stably intheir sockets.

Observations on the theory of the epithelialattachment of GottliebThe consistency of findings raised the question ofre-examining the theory of epithelial continuity, asit had been interpreted by Gottlieb regarding thefunctions of the epithelial attachment between the

Fig. 68 Three cylinders immediately after insertion, two withemerging posts. The central one has internal threading.Fig. 69 Two cylinders with short external threaded posts.

Fig. 70 Three short emerging posts six months followingsurgery. Note their minimal height (arrow), which protects themfrom external mechanical stress.

10 The scanning microscope and Karl Donath’s ground section technique had not been invented yet.

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Fig. 71 Diagram of the analyzed histological sections showing the different cutting directions. Fig. 72 Some of the hundreds of specimens that were prepared. Fig. 73 Full-thickness section of the bone tissue and the basket with external threading, obtained

with a carborundum disk six months following placement. Note the regeneration of bone tissue above the uppermost portion of the basket.Fig. 74 Macroscopic section of a cylinder with a threaded post, removed six months after placement, and of the corresponding includingbone tissue. The two arrows indicate the mucosal level before removal, performed in order to visualize the tissue immediately underlyingthe neck area, consisting of healthy and perfectly osseointegrated bone. The histological examination was performed around the post.

Fig. 75 Collection of mucosa for the histological examination of the neck area of the emerging post, performed by means of perpendicular sections. Fig. 76 Anatomopathological and histological appearance of a mucosa section (orthogonal to the emerging

post) adhering to the implant neck, just above the epithelial attachment area. Note the absence of the keratin layer on the side facing the implant and the healthy appearance of the basal layer, without any inflammatory infiltrations in the underlying corium.

Fig. 77 Higher magnification of the histological specimen of the mucosa and corium in contact with an emerging post.The epithelium shows no sign of inflammatory infiltrations

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mucosa and the natural teeth, and suggesting a dif-ferent etiopathogenesis of periodontitis. Interestingas this hypothesis may have seemed, however, fur-ther confirmation would be necessary before itsclinical validity could be demonstrated.The topic would be discussed extensively in mybook Le patologie occlusali. Eziopatogenesi e terapia,published 30 years later with conclusions that, atthe time, I could not have predicted. I am citingthis detail simply to emphasize to the reader thatthis study, conducted long ago and seemingly un-related to occlusion problems, laid the scientificgroundwork for the chapters in the book that fo-cused on the direct cause-effect relationship linkingthe balance between static and dynamic occlusionwith the life of the implants, regardless of any mi-crobial cofactors.According to Gottlieb, Orban and many authorswho still agree with their theories, the epithelial at-tachment joins the mucosal epithelium to the toothenamel, “both of which deriving from the same em-bryonic ectodermal tissue.” It thus acts as a barrier,preventing pathogens from penetrating the under-lying tissues, as otherwise—according to this theo-ry—they would promote gradual destruction of thedeep supporting tissues of the tooth. In Le patologie occlusali. Eziopatogenesi e terapia, Ihighlighted the weaknesses and contradictions ofthis “exclusive” etiological concept, which shouldinstead include occlusal imbalance, of which it rep-resents the predominant factor. At the time of my study on dogs, these conceptsgreatly added to skepticism about the reasonableuse of implants because, according to the afore-mentioned authors, it was unthinkable that a sim-ilar defensive barrier could be achieved betweenmetal and the mucosa. The clinical, radiographic, anatomical, histologicaland anatomopathological findings regarding the tis-sues in contact with my experimental implants,

which had short emerging posts and were kept in aquiescent state during reparative inclusive osteoge-nesis, instead showed that the peripheral seal,which they were certainly lacking, did not negative-ly influence their permanent biological integration.Before me, only Weinemann (23) had postulatedthe existence of a very different type of contact withrespect to the one theorized by Gottlieb and Orbanat the implant/mucosa interface. In 1956 he noted,“I no longer believe that the epithelium of theenamel organ merges with the oral epithelium dur-ing tooth eruption. I instead believe that a differentsecondary attachment replaces the former one. . . .With implants, this attachment can be compared tothe biochemical mechanism that allows numerousinsects to adhere to other structures by secretingvarious substances; this may also be possible whenthe enamel is artificially replaced by inert materi-als.11 Perhaps the epithelium is connected to theimplant the way cement is to an erupting tooth.”Forty years later Taylor (24), Listgarten and Lai(25), and Gould, Brunette and Westbury (26) alsoagreed that, thanks to the presence of hemidesmo-somes in the cytoplasm, epithelial cells could ad-here to inert inorganic and biocompatible materi-als. Nevertheless, I believe that their assumptionsare inaccurate since, with both an optical and scan-ning microscope, I have never observed any junc-tion between the mucosal epithelium and the met-al structures. The real seal is between the deep mu-cosal layer and the periosteum above the bone tis-sue that includes the implants, when it is apposedwithout the interposition of fibrous tissue. Anyone dealing with implants can verify it on theirown patients who have functional and stable im-plants, using a simple probe as shown in my bookLe patologie occlusali. Eziopatogenesi e terapia.12

On the behavior of the including bone tissueAll implants placed in the cavities where the central

11 Biocompatible.12 See Chapter 5, Part 2, of my book Patologie Occlusali. Eziopatogenesi e terapia. Milan: Masson, 1993.

Fig. 78 Hemimandible on the autoptic table. The arrow points a buried basket. Fig. 79 Radiograph.Fig. 80 X-ray of the two inclusions, one with an externally threaded post and one with an internally threaded post.

78 79 80

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bone core had been removed were perfectly os-seointegrated even though they had a short emerg-ing post. The new bone had apposed on thesestructures in a mirror image and completely filledthe voids without the interposition of fibrous tissue(Figs. 78–80).The bone in contact with the metal structures wascollected for histological examination after dem-ineralization by immersion in trichloroacetic acid,renewed 3 times/day for 30 days. The histological sections confirmed the radiograph-ic findings; the complete absence of fibrous tissueis quite obvious in the two specimens I have repro-duced here at the highest magnification (Figs. 81,82). One can clearly observe the more intense stain-ing of the new tissue, due to the greater stainingaffinity of mucopolysaccharides, which are abun-dant in young tissue.13 It is fascinating to note theconstant presence of a different lamellar architec-ture between the newly formed bone, apposed tothe metal structures, and the older bone tissue. An interesting image shows the bone section ap-posed around the lowermost (and partially sub-merged) portion of a short emerging post, where wecan see that the tissue adhering to the post forms anarc with a smaller diameter (Fig. 83). I have addedarrows to some of the pictures to highlight how themagnification of the histological pattern makes itpossible to identify osteocytes and their nuclei, en-capsulated in their mineralized niches at this point.The arrow outside the semi-arch apposed on thesurface of a basket indicates that the tissue residues,which the microtome has moved into the emptyspace, are produced by the microtome blade usedto prepare the sections to be examined (Fig. 84).Furthermore, the complete absence of fibrous tis-sue in each of my exhibits testifies that the “emerg-ing” implants with a short post, and kept in a qui-escent state during the reparative osteogenic phase,were always osseointegrated via the apposition ofnew bone mirroring their structures.This proved that keeping the implants below themucosa was not strictly required; it was sufficient toprevent the short emerging post, which maintainedcommunication with the external environment,from transmitting the mechanical stress of thetongue to the submerged portion during swallow-ing and chewing.I also obtained excellent osseointegration, withoutthe interposition of fibrous tissue, using truncatedcone implants inserted in cavities made with thesame conical drills employed during the first phase

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13 In this case hematoxylin-eosin.

Fig. 83 Healthy including bone, in contact with the deep structure of acylinder from which it was artificially removed for the histologicalexamination (hematoxylin-eosin 180x).

Fig. 81 View of the bone tissue around a basket. Note the wavycontour indicating tissue reorganization around the implant holes, andintense staining testifying to its new formation.Fig. 82 Close-up at high magnification. Note the different direction inthe architecture of the lamellae of the old and new bone tissue, and theabundant osteocytes that had just matured (hematoxylin-eosin 130x).

81

83

84

82

Fig. 84 Another specimen: the arrow indicates the stretching of alamella of newly formed tissue, due to the use of a microtome(hematoxylin-eosin 180x).

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of the study on the biocompatibility of implant ma-terials.

How to use the emerging postsAnother problem to solve involved finding a way toadd prosthetic abutments to the short emergingposts of my last two-phase implants once they werecompletely osseointegrated. Therefore, I threadedthem, since screwing them in was the only way toguarantee that they would be joined properly. Ichecked a set by introducing it into the edentulousmandibles of the last animals and leaving it in placefor six months with the threaded portion slightlyprotruding from the mucosa. The histological andanatomopathological findings confirmed the resultsthat had already been observed with the previous im-plants. The full thickness sections performed with acarborundum disk showed identical anatomic pat-terns, demonstrating—also macroscopically—theneoformation of bone tissue outside, inside andacross their vented structures, as well as above theocclusal surface and around the lowermost portionof their short threaded emerging posts (Figs. 85–90).

Studies on occlusal loadThis third part of the research (which, as mentioned,took five years) provided enough data to switch toimplant experimentation on humans, but I did nothave as the positive certainty I needed regarding theconsequences of occlusal load, which was indispen-sable for their prosthetic use.

I could easily have used dogs again, but their differ-ent teeth morphology and TMJ joint mechanicswould have made it impossible to draw conclusionsapplicable to humans.14

Furthermore, I had to plan too many anesthesias: forimpression taking, crown fitting, cementation andperiodic checkups. Dogs do not tolerate prolongedand repeated anesthetic procedures well.15

Therefore, load tests could only be performed on hu-mans.At that time my knowledge of gnathology was limit-ed to the scanty technical baggage of the state of theart of the dentistry of four decades ago, with only afew nebulous concepts of occlusion that had beenrelegated to the background by the resurgent meth-ods of the historical gingivectomies of Riggs, Picker-ill, Black, Nodine and Neumann (27–31), enhancedby the introduction of new instruments for peri-odontal surgery from the United States, and by thefascinating periodontal reconstruction techniques ofKirkland, Orban, Goldman, Schluger, Fox, andGlickman (32–36). Despite the temporary therapeu-tic results of their methods, I still had too many ques-tions about the real causes behind the mobility andexpulsion of many “healthy” natural teeth in thesame mouth where other elements, in seeminglyanalogous conditions, remained quite stable andshowed no recession of the supporting tissues.How could I undertake a reliable investigation aboutthe influence of occlusal load on the stability of im-plants over time if I still did not understand why

Fig. 85 Hemimandible after decortication. Figs. 86-90 Histological section orientations of the bone tissue, performed around the osseointegrated baskets.

14 Dogs’ molars differ from those of humans. Dogs have “tearing teeth” because their masticatory apparatus lacks the lateral movements and canineguidance that are instead typical of humans.

15 During the first phase of the study I lost two dogs due to excess anesthesia.

85 86 87

88 89 90

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many natural teeth, without any bacterial plaque orcalculus, gradually lost their stability? Aware of mylacunae regarding the etiopathogenesis of the grad-ual destruction of the periodontium of these ele-ments, I decided to postpone the last phase of thestudy so that I update my knowledge on the subject.Therefore, I published the results of the first threephases of the study on dogs, postponing tests of thefourth phase on humans, which—tellingly—werecompleted 40 years after the publication of my bookLe patologie occlusali. Eziopatogenesi e terapia. Here I have cited the conclusions of the experimentsof my early years, published in 1962 with the title“Ricerche anatomopatologiche e deduzioni clinico-chirurgiche di novantun impianti alloplastici in ven-totto animali da esperimento”. This study won thetop “Campione d’Italia” prize for the best scientificwork presented at the International Italo-Swiss Den-tal Congress that year.16

I do not know how the bone that has encapsulat-ed these implants will react to future testing of aphysiological load. Nevertheless, I can predictwhat will happen in the event of overloading:they will be expelled, but with no greater riskthan that observed when natural teeth subjectedto similar pathological stresses are expelled. I can-not say if the physiological loads will transformthe bone, directly apposed to the metal structures

of the implant in a quiescent state, into fibrousand less resistant encapsulation or into moredurable osteofibrosis, or if it will maintain thesame original histological architecture at length.It is with this same doubt that I am facing thequestion—unsolved so far—of the eventual ben-efits of cushioning achieved through mechanicalmeans.For the time being, however, I can assume thatsimilar experiences in the human field, performedwith the same technique employed with animals,should not entail any greater risks than those ofminor routine dental surgery. In any event, I amconfident that if the area of our specialty dealingwith periodontal disease achieves the goals cur-rently set by new studies on the rehabilitation ofstatic and dynamic occlusion, together with oraland general hygiene, this will avoid many mis-takes, not to mention incorrect assessments,about the potential therapeutic use of endosseousimplants as an alternative to traditional prosthe-ses (Figs. 91, 92) (37).

I could not have predicted that this research on im-plants, which I had conducted with youthful curios-ity and sparing no efforts—thanks to the help andselfless collaboration of Armando Santi of the Insti-tute of Special Pathology and Veterinary Surgery ofthe University of Milan and Antonio Stigliani, Direc-

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16 Awarded by Branzi, Benagiano, Giosuè Giardino and Giacomo Armenio, Directors of the Dental Clinics of the Universities of Bologna, Rome, Naplesand Bari, respectively.

Fig. 91 The original cover of Pasqualini’s publication (1962).Fig. 92 Detail of the scientific work that anticipated the current concepts of modern implantology.

91 92

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tor of the Institute of Pathological Anatomy of theUniversity of Modena, and the unconditional sup-port of the Dental Unit of my institute, headed by Ar-rigo Provvisionato (I was his assistant), and its latedirector, Benito Vernole—would represent the mostsweeping and comprehensive experimental researchon the topic in worldwide literature. Moreover, Icould not foreseen that the same principles I had justdemonstrated scientifically would be presented 15years later by P. I. Brånemark, of the University ofGothenburg (38). In the years immediately following the publicationabout my implants, I concluded the final experimen-tal phase of the study on the influence of masticato-ry load, bringing in the same scientific curiosity thathad made me so passionate about the issue of im-plant biocompatibility and osseointegration. There-fore, I entered the vague field of occlusion, trying tounderstand the different viewpoints of periodontalsurgeons and gnathologists, and forcing myself tolearn—and personally verify—all of their differentand contrasting indications.This led to a better understanding of the variousfacets of the problem and the narrow boundariesraised by several “dogmatic” concepts of certainpathological manifestations and the uncertain etiolo-gy of the two main causes of tooth loss: dental cariesand periodontal disease.The solution to these problems, which initially inter-ested me only in relation to the conclusion of the firstthree phases of my research into implants, openedup a much broader horizon that covers virtually allof the pathophysiology of the oral cavity.The fourth phase, examining the effects of occlusalloading on the life of loaded implants, was conclud-ed a decade later at a congress I attended as the mainspeaker, where I first spoke about “implantology andapplied gnathology” and showed that, aside fromrisk-taking and/or surgical inexperience, the samecauses that lead to success or failure of implants arealso responsible for the maintenance or loss of natu-ral teeth (39).Immediately thereafter I announced the positive re-sults I had obtained by applying the protective prin-ciple of reparative osteogenesis, which I had testedwith baskets, to my polymorphic blades (39–45,49).

NoteIn 1959 Benaim (46) placed vented cylindrical im-plants made of Stellite—similar to the kind I hadjust used on dogs—directly in humans. They werevented hollow cylinders with four circular openings;the occlusal portion had internal threading for theinsertion of a prosthetic abutment three weeks after

implantation. Benaim left the internal bone core that I had learnedto remove, as I had already observed its dangers anddisadvantages. His two-step implant, morphological-ly very similar to my first completely buried cylin-ders (and Greenfield’s) was designed solely to avoidmicrobial infections during the healing of the mu-cosa and was to be used after three weeks, when thesuture had healed completely. All his implants wereexpelled for the same reasons that caused the expul-sion of my first cylinders: the risky presence of thecentral bone core, as I had identified.In 1958 Cherchève had designed an implant henamed “sleep away,” consisting of an internallythreaded screw without a post. Throughout the heal-ing phase the screw was left “resting” below the mu-cosa. When healing was complete, a screw was intro-duced through the oral mucosa and screwed into theinternal threading of the first screw. Cherchève’s two-step implant had very limited success and was aban-doned. It is easy to see that it too was based on theembryonic principle of osseointegration, which un-fortunately did not take place due to excessive com-pression of the implant, which had been forced intobone tunnels that were too narrow (47). Also in 1958, Thomas F. Kiernan (48) patented avery complicated two-step buried implant. It was atruncated stainless-steel cone with a long internalthread, next to which there were small tunnels withlittle tubes, also made of stainless steel, that expand-ed toward the outside after a long post was insertedin the implant, thus ensuring greater retention. Withregard to this implant as well, we have no informa-tion about practical experiments, nor if the implantwas successful.

References

1. VENABLE C.S., STUCK W.G., BEACH A. The effects onbone of the presence of metals; based upon electrolysis. Anexperimental study. Ann Surg 1937;105:917. 2. VENABLE C.S., STUCK W.G. The internal fixation of frac-tures. Springfield, Illinois (USA): Edit. Thomas; 1947.3. KEY A.J. Stainless steel and Vitallium in internal fixationon bone. Arch Surg 1941;43:614.4. BERTOLINI A.M., MALIZIA E. Gli elettroliti in biologia ein medicina. Milano: Editrice Ambrosiana; 1951.5. MARZIANI L. L’uso del tantalio nella chirurgia ricostrutti-va con speciale riguardo all’impianto dentale subperiosteo.Proceeding of the 11th International FDI Congress; London.1952.6. SCIALOM J. A new look at implants: a fortunate discove-ry: needle implants. L’Information Dentaire 1962;44:737.7. MAGGIOLO G. Manuel de l’Art du Dentiste. Nancy (Fran-

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ce): Editions C. Leseure; 1909.8. PAYNE R.E. Implantations of tooth by silver capsule me-thod. Dent Cadmos 1901;43:1401.9. GREENFIELD J. Una radice artificiale. Lab Progr DentRev 1911;XV.10. GREENFIELD J. Implantation of artificial crown andbridge abutments. Dent Cadmos 1913;55:364.11. STROCK A.E. Experimental work on a method for repla-cement of missing teeth by the direct implantation of a me-tal support into the alveolus. Am J Orthod Oral Surg1939;25:467.12. STROCK A.E., STROCK M.S. Further studies on the im-plantion of inert metals for tooth replacement. Alpha Omega1949;43:107-10.13. BENAIM L. Implants viewed realistically. L’InformationDentaire 1962;44:519.14. CHERCHÈVE R. Perfezionamento della tecnica degli im-pianti alloplastici endoossei. Proceeding of the 2nd Interna-tional Symposium; Pavia, Italy. 1959.15. LEHMANS I. Risultati ottenuti in due anni di esperimen-to con l’impianto ad arco. Riv Ital Stomatol 1946;4:409.16. PERRON ANDRES C. Impianti-eteroplastici endomascel-lari con la vite di Formiggini. Prot Dent 1957;2:8.17. PERRON ANDRES C. Emplantes intro oseos aloplasticoscon espirales de Formiggini. Ann Med 1958;XLV(febb).18. PERRON ANDRES C. Biopsia di un impianto endoosseodi Formaggini. Prot Dent 1959.19. ZEPPONI F. Protesi fisse a mezzo di infibulazioni endo-mascellari. Riv Ital Stomatol 1955;1:45.20. LINKOW L.I., CHERCHÈVE R. Theories and techniquesof oral implantology. St. Louis (USA): CV Mosby Co;1970.21. GOTTLIEB B. Der Epithelansatz am Zahne. DeutscheMonatsschrift für Zahnheilkulde 1921;39(5):142-7.22. GOTTLIEB B. Zur Biologie des Ephitelansatzes und derAlveolarrandes. Deutsche Zahnärztliche W 1922;25:434.23. WAINEMANN J.P. Biological factors influencing implantsdenture success. Implant Dent 1956;2:12. 24. TAYLOR A.C. Adhesion of cells to surfaces. New York(USA): Academic Press; 1970.25. LISTGARTEN M.A., LAI C.H. Ultrastructure of the intactinterface between an endoosseous epoxy resin dental implantand the host tissue. J. Biol Buccale. 1975;3:13-28. 26. GOULD T.R.L., BRUNETTE D.M., WESTBURY D.M. Theattachment mechanism of epithelial cells to titanium in vitro.J Periodont Res 1981;16:611-616. 27. RIGGS I.M. Phyorrea alveolare. Dent Cadmos1882;24:524.28. PICKERILL H.P. Prevention of dental caries and oral sep-sis. London (UK): Ed. Baillière Tindal Co; 1912.29. BLACK C.V. Special denture pathology. Chicago (USA):Medico Dental Publishing Co; 1915.30. NODINE A.M. Surgical treatment of phyorrea. Dent Cad-mos 1921;63:345.31. NEUMANN U. Atlas der radical Chirurgische behandungder paradentosen. Berlino: Ed. Meuser; 1926.

32. KIRKLAND O. Surgical treatment of periodontoclasia:modified flap operation. Am J Dent 1932;19:1911. 33. ORBAN B. Indications, technique and postoperative ma-nagement of gingivectomy in the treatment of periodontal. JPeriodontol 1941;12:89. 34. GOLDMAN H.M. The development of physiologic gingi-val contours by gingivoplasty. Oral Surg Oral Med Oral Pa-thol 1950;3(7):879-88.35. GOLDMAN H.M., SCHLUGER S., FOX L. Periodontaltherapy. St. Louis (USA): CV Mosby Co; 1956.36. GLICKMAN I. Clinical periodontology. The periodon-tium in health and disease. Philadelphia (USA): Saunders Co;1959.37. PASQUALINI U. Ricerche anatomopatologiche e dedu-zioni clinico chirurgiche di 91 impianti alloplastici in 28 ani-mali da esperimento. Riv Ital Stomatol 1963;12 e 1963;1. 38. BRÅNEMARK P.I., Hansson BO, Adell R, Breine U, Lin-dström J, Hallén O., Ohman A. Osseointegrated implants inthe treatment of the edentulous jaw. Experience from a 10-year period. Scand J Plast Reconst Surg 1977;16.39. PASQUALINI U. Impianto protesi e gnatologia applicata.Proceedings of the National Congress of Alloplastic Implants.Mestre, Italy: Ed. A.I.I.A; 1972.40. PASQUALINI U. Endosseous implants. Protection of re-parative osteogenesis with the “screw stump”. Dent Cadmos1972 Aug;40(8):1185-94.41. PASQUALINI U. Subcortical bars: principles and technicof a new endoossal implantation. Personal technic. Preventi-ve note. Dent Cadmos 1972 May;40(5):672-93.42. CAMERA A., PASQUALINI U. Comportamento dell’epi-telio umano intorno ai perni uscenti degli impianti endossei.Associazione Italiana Impianti Alloplastici 1972;3:12-7.43. PASQUALINI U. Ricerche isto-anatomopatologiche edimplantologia. Associazione Italiana Impianti Alloplastici1972;5:40-7.44. PASQUALINI U. Impianti endossei: istologia comparatadella “zona del colletto” in un dente naturale, due monconiin incavo e tre viti di Tramonte. Associazione Italiana Impian-ti Alloplastici 1972;6:15-20.45. PASQUALINI U. L’impianto protesi nel monoedentuli-smo dei denti frontali superiori. Rivista Europea d’Implanto-logia 1978;1:60.46. BENAIM L. Presentazione di un impianto tubolare endo-osseo. J Stomat Inf Dent 1959;16:7.47. CHERCHÈVE R. Les implants endo-osseoux. Paris: Li-brairie Maloine; 1962.48. KIERNAN T.F. jr. Individual tooth implant. US patent N.2.857.670; 1958.49. MELICA V.M. L’osteointegrazione ha origine italiana. IlGiornale dell’Odontoiatra 1993;X(12):15.

Figs. 1, 6, 7, 11–13, 24, 26, 28, 29, 31–36, 38, 41, 42, 44, 52, 53–54,

56, 59–61, 65–70, 74–77, 83. From Pasqualini, Le patologie occlusali.

Eziopatogenesi e terapia. Milan: Masson, 1993.

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TREATISE OF IMPLANT DENTISTRY CHAPTER III

When Pasqualini concluded his studies ondogs, interest toward subperiosteal im-plants—oddly considered less risky

than endosseous ones—was dwindling (Fig. 1).The first failures of those implants, along withtheir challenging surgical removal, began todampen the initial enthusiasm aroused immedi-ately after G.S.A. Dahl, Mazzotto-Sabras, L.Marziani A. Gershkoff and N.I. Goldberg had pro-posed, modified and publicized them1 (1–6) (Fig.2).In the same decade (1960–70) endosseous im-plants underwent important evolutions that canbe summarized as follows:1) modifications of the spiral infibulations of

Formiggini, Zepponi, Cherchève, Perron An-dres and Jeanneret;

2) the conversion of Formiggini’s spiral into Mu-ratori’s hollow-screw implant and Linkow’sVent-Plant;

3) Scialom’s new tripodial tantalum needle tech-nique;

4) Tramonte’s new self-threading screw tech-nique.

The descriptions of the modifications of the spi-rals of Formiggini, Zepponi, Cherchève, PerronAndres and Jeanneret were described by the au-thors in their highly detailed publications. Al-though both Muratori’s hollow screws andLinkow’s Vent-Plant were derived from the firstFormiggini spiral implant, they diverge fromthem so much that they can rightly be consideredfully fledged original implants. Scialom’s new tripodial tantalum needle methodand Tramonte’s self-threading screw technique,which also appeared in the 1960s, will be covered

in subsequent chapters, as they effectively repre-sent two new implant concepts.

THE EVOLUTION OF ENDOSSEOUSIMPLANTS IN THE 1960s

1 For this technique, other important authors include Trainin, Lee, Benaim, Bello, Sol, Salagaray, Borrel Ribas, Pelletier and Maurel (7–12).

Fig. 1 Lower subperiosteal implant checkups at 1–3–5 years(1990–95).

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Muratori modified andtransformed Formiggini’s spiral

Giordano Muratori entered the small world of im-plantology with a report published in Paris(1961) about several successful cases treated withFormiggini’s screw technique (13).The following year (1962) he presented an initialmodification of the original spiral, made of castVitallium with threading along two vertical sup-ports, leaving a wide gap in between. The threadsthen continued along a solid cylindrical shaftwith a slightly smaller diameter.Muratori’s screw consisted of an “active” en-dosseous portion, characterized by a short hollow

spiral with sharp edges, which extended into along thinner round shaft ending with a rectangu-lar section designed to be grasped with a torquewrench. A gold cap could be secured over this section forthe prosthetic overstructure (Figs. 3, 4). In 1967he created a new screw from a block of titanium,a completely biocompatible material that hadbeen introduced recently and was first employedin dental surgery by Tramonte.2

The use of titanium made it possible to sharpenthe threads and permitted mechanical precisionunattainable with cast Vitallium. The mass-produced screws were classified as“normal” (with a thread diameter of 2 and 4 mm,and a total length of 16 mm) and “long” (with athread diameter of 3-4 mm and length of 21 mm)(Fig. 5).Muratori’s implants came with an elaborate toolkit to be used for their exact placement in previ-ously calibrated and tapped bone cavities. UnlikeCherchève, Muratori employed a lance drill as thefirst cutting tool for the alveolar ridge, an instru-ment he referred to as a perforating drill. This in-strument assured much more precise cutting ac-tion than round burs, and it easily penetrated theouter layer of compact cortical bone, drilling atthe depth established for the normal or longscrews and preparing the terrain for the cylindri-

The evolution of endosseous implants in the 1960s III

2 We will discuss Stefano Tramonte in Chapter 4, part 2.

Fig. 3 Original Muratori screws.A gold cap can be screwedonto the right side.Fig. 4 Detail of Fig. 3 showing the small screw for insertion ofthe prosthetic overstructure.

Fig. 2 Another first-generation lower subperiosteal implantremoved due to fracture of the metal frame (arrow).

Fig. 5 Other Muratori screws.

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cal helical drill (Figs. 6–8).To insert the screws with 3-mm threads, the au-thor recommended using a 2.25-mm “expanding”cylindrical drill for soft and cancellous bone, anda 2.50-mm drill for compact bone. To insert the4-mm screws into the cancellous bone, the authoradvised using the 2.75-mm expanding drill, fol-lowed by the 3-mm drill if resistance of compactbone was encountered. When long screws wereused, these drills could continue to be used, stop-ping the insertion at the second circumferentialnotch. The tunnels were completed with “bone taps” (al-so provided with reference notches) to be usedmanually to create the deep insertion site for thespiral portion of the implant, avoiding dangerous

compression of the bone tissue housing it whilemaintaining its retentive characteristics (Figs.9–11).A second set of instruments, longer than the firstones, allowed implant insertion even in areaswhere adjacent teeth could prevent the head ofthe contra-angle from moving axially toward theridge. Muratori’s kit also had a ratchet wrench that, ap-plied to the back of Doriot contra-angles, permit-ted their manual rotation, so that thanks to a spe-cial mandrel they could insert both tappers andscrews even in distal areas. Today these peculiarcontra-angles are hard to find on the market.A series of pre-made gold “transfer caps” allowedthe laboratory to position them precisely on the

Fig. 6 Diagram of the Muratori tool kit. Fig. 7 Original tool kit.Fig. 8 The original instruments used for inserting a Muratori screw.

Fig. 9 Left to right: lance drill, expanding drill and tapper.Fig. 10 Drill and tapper for compact bone.

Fig. 11 Perforating lance drill (left), drill for compact bone (center), and expanding drill (right).

6 7 8

9 10 11

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emerging implant portions and screw them in,representing the first removable structures in im-plantology. This technique is clearly illustrated inthe author’s book Multi-type oral implantology(1972) (14–19) (Figs. 12, 13). Muratori’s screws were designed to be inserted sothat the neck protruded a few millimeters abovethe oral mucosal surface. The purpose of this fea-ture was to immediately connect readymade pros-thetic abutments of different heights, and notmerely to avoid mechanical stress on the lowerimplant portion. Placed very deeply into thebone, this portion was mechanically stable imme-diately after insertion and could counteract over-loading before reparative osteogenesis was com-plete.Muratori performed his first operations by insert-ing the hollow screws directly through the mu-cosa. However, after several failures due to inad-equate positioning, he recommended open sur-gery for critical cases. We have published several radiographs, courtesyof the author, that show the progressive and ex-cellent osseointegration of these screws (Figs.14–16).

Linkow’s Vent-Plant

In 1963 Leonard Linkow—unknown in Europe atthe time—devised a further modification of thehollow spiral screws, changes that Cherchève andMuratori had already made to Formiggini’s spiral.His implant, which he dubbed the Vent-Plant,was initially made of Vitallium and later of titani-um (20).Chronologically, Linkow’s Vent-Plants should bediscussed after Scialom’s tripodial tantalum nee-dle and Tramonte’s self-threading screws. Howev-er, since they are a direct elaboration of the hol-low screws (although they did not bring any sub-stantial improvement to them), from a didacticstandpoint it is more appropriate to discuss themat the end of this chapter.Titanium Vent-Plants consist of an open portion,delimited laterally by two bars that are joined api-cally to a plate (or a small ring or even a simplehorizontal bar), followed by another portion thatis also hollow but is threaded, ending in a solidsection that extends outward and terminates witha smooth square-section extension, designed sothat it can be screwed and connected to the pros-thesis (21, 22). Vertical grooves between the spirals were de-signed to facilitate entry (Fig. 17).

In discussing this, Linkow wrote: “The modifica-tions underwent dozens and dozens of variations.The vent was enlarged and reduced in size; it waslengthened and shortened. The spiral portion wasreduced apically from the earlier models. Enoughvariation was inherent in the design so that avent-plant suitable for almost any site was avail-able and could be utilized in many edentulous ar-eas” (Fig. 18).Preparation of the tunnel for the housing of theVent-Plant was then performed with a round burthat permitted subsequent widening with a cylin-


Fig. 12 Muratori’s original drawing.Fig. 13 X-ray of three implants (1966).

Fig. 14 Another original drawing.Fig. 15 X-ray of two loaded implants (1970).Fig. 16 Case of two edentulous ridges treated with the screws ofMuratori and Cherchève. On the right: detail of the perfectosseointegration of the retentive structure of a Muratori screw.

12 13

14

16

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drical helical drill. The author made further com-ments. “As the implant was screwed into thebone, the vascular bone chips were deposited in-side the V-shaped ‘sluice-ways’ and ended up in-side the vent, thereby eliminating any excessivepressure to the surrounding bone. The self-tap-ping feature reduced the danger of the priorpreparing of too wide a site for the implant inser-tion with a tapping instrument. Upon insertion,therefore the vent-plant was much more securethan most other forms of spiraled endosseous im-plants that cannot ‘tap’ their own way into thebone. Immediately after the vent-plant wasscrewed into position it could also be unscrewedout of the bone and removed, and all of the bonechips were evacuated out of the vent. The implantwas then rescrewed into the bone allowing ablood cloth to form inside the vent which led tofibrous tissue formation which eventually formedbone.”The author noted that this technique was laterimproved by removing a bone plug from themandibular symphysis using a hollow milledtrephine; the graft was placed into the vent of theimplant, before the second insertion. Accordingto Linkow, the grafting would act as a scaffold fornew bone growth, which would gradually resorband replace it. The bone harvested from themandibular symphysis was later crushed before

the chips were placed into the vent “as most ofthe bone core from the base of the mandible wasavascular”.To prevent the type of failure Linkow attributedto the low compatibility of titanium (sic!), he al-so attempted to coat several Vent-Plants with alayer of aluminum dioxide, but the results wereless than brilliant, as he honestly acknowledged(Fig. 19).In his most recent book Linkow added several X-rays of perfectly osseointegrated Vent-Plant im-plants (Figs. 20-23).

RemarksI have quoted Linkow’s words from the first vol-ume of his excellent book Implant Dentistry Todaybecause, despite his current fame and well-de-served reputation as a pioneer of implantology,these implants are not only are virtually unknown,but they have essentially never been used in Eu-rope. Therefore the following considerations mustbe made.The concept of self-tapping, using the implant be-fore reinserting it into the site cleaned of boneresiduals, can also be applied profitably to otherscrew implants. Equally remarkable is the idea ofgiving the Vent-Plant an initial smooth portion—open and without any spirals—that should act asa guide for engagement of the implant and a non-compressive storage chamber for the bone frag-ments recovered after its removal in the firstphase. Instead, I consider the chin-bone harvest-ing procedure, performed to add “ground” bone tothe bottom of the Vent-Plant insertion tunnels, tobe entirely useless. The idea of using bone coresharvested at the bottom of the implant bore anddirectly inserted into the apical hollow portion ofthe implant is nothing short of dangerous and canpotentially cause failure due to bone resorption.As to the risk associated with this method, thiswas experimentally demonstrated in the secondphase of Pasqualini’s research on dogs. Linkowhimself stated that he did not achieve good resultswith it.

Fig. 18 Titanium Vent-Plants. Fig. 19 The implant after coating (aluminum dioxide).

Fig. 17 Three Vitallium Vent-Plants (1963).

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In any event, Linkow’s Vent-Plants, together withthe hollow screw implants of Cherchève and Mu-ratori, can be classified among the best screw im-plants designed up to that point (23–25).

References

1. DAHL G.S.A. Subperiostal implants and superplants. DentalAbstracts 1957;2:685.2. MAUREL G. E COLL. Implants métalliques sous-périostéspour édentés totaux et partiels. Technique et résultat. Rev FrOdontostomatol 1956;7.3. MARZIANI L. L’uso del tantalio nella chirurgia ricostruttivacon speciale riguardo all’impianto dentale subperiosteo. Atti del-l’XI Congresso Internazionale FDI; Londra. 1952.4. MARZIANI L. Implantation sous-périostée en tantale. Rev FrOdontostomatol 1959;5.5. GERSHKOFF A., GOLDBERG N.I. Implant dentures. Phila-delphia (USA): J.B. Lippincott; 1957.6. GERSHKOFF A., GOLDBERG N.I. Implant dentures. Indica-tions and procedures. Philadelphie (USA): J.B. Lippincott; 1957.7. TRAININ F.B. Subperiosteal implants. Le Journal DentaireBelge 1960 Jan-Feb;51:31-40.8. BENAIM L. Implants viewed realistically. L’Information Den-taire 15 Feb 1962;44:519-528 e 22 Feb1962;44:617-624.9. BELLO B., ESTEVES AREAL P. Denturas implantades. Rio deJaneiro;1956.10. SOL B., SALAGARAY F. New type of implants. Rev Fr Odon-tostomatol 1963 Aug-Sept;10:1106-1124.

11. PELLETIER M. Considération clinique et prothétique sur latechnique des implants métalliques sous-périostés. Rev FrOdontostomatol 1958;5.12. BORREL RIBAS A. Pràctica de la Implantologìa. 20 años deexperiencia en implantologìa endoòsea. Sabadell: Ed.G.E.D.E.I.; 1985.13. MURATORI G. Quelques cas d’implants endo-osseux. RevFr Odontostomatol 1961.14. MURATORI G. Histological examination of an implant afterfive years. Newsl Am Acad Implant Dent 1967 Jul;16(3):63-4. 15. MURATORI G Intra-osseous alloplastic implants in the jaws.Histology and radiology from 5 to 7 years later. Minerva Chir1967 Jun 15;22(11):687-88.16. MURATORI G. Endooseous implantation. From interven-tion to prosthesis. 8. The immediate implantation general me-thods. Dent Cadmos 1968 Aug;36(8):1113-54.17. MURATORI G. Personal method of endosseous implant forremovable prosthesis. J Anglocont Dent Soc 1969 Apr;(20):23-6. 18. MURATORI G. L’implantologia orale multitipo. Bologna: Ed.Marino Cantelli; 1972.19. MURATORI G. Oral implantology: historical-scientific rela-tionship.4. Dent Cadmos 1989 Feb 15;57(2):15,17-23,25-30.20. LINKOW L.I. Clinical evaluation of the various designed en-doosseus implants. J Oral Implant Transplant Surg 1966;12:35-46.21. LINKOW L.I. The age of endoosseus implants. Dent Con-cess 1966;18:4.22. LINKOW L.I. The radiographic role in endoosseus implantinterventions. Chronicle 1966 Jun;29(10):304-11.23. LINKOW L.I. The versatility of implant interventions. DentConcepts 1966 Fall;10(2):5-17.24. LINKOW L.I., CHERCHÈVE R. Theories and tecniques oforal implantology. St. Louis (USA): CV Mosby Co; 1970.25. LINKOW L.I. Implant dentistry today. A multidisciplinaryapproach. Padova: Ed. Piccin; 1990.

Figs. 16–23 Courtesy of Leonard Linkow.


Fig. 20 An implant immediately after placement and a drill inplace for another insertion.Fig. 21 The two implants.Fig. 22 Definitive prosthesis placed on two implants loadedfor two years. Note the perfect adaptation of the bonesurrounding them.Fig. 23 Radiographic checkup of a Vent-Plant at 12 years.

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TREATISE OF IMPLANT DENTISTRY CHAPTER IV - Part I

Scialom’s pins, Tramonte’s self-threadingscrews and Linkow’s blades, represented themost important dental implant innovations

of the 1960s and were paralleled by marketingcampaigns. It was effectively the latter, rather thanthe scientific review of their therapeutic value, thatcontributed to their circulation in the dental worldand made inroads with public opinion, which waseven more receptive. This is proven by the fact thatscientific demonstrations about the need to shieldimplants that are not stable yet from externalstress—a claim validated by a trial lasting five years,the sacrifice of twenty-eight animals and the jointefforts of three university institutes—would gothrough further studies and an extensive marketingcampaign before becoming the most widespreadimplant technique worldwide three decades later.

Jacques Scialom’s needle implants

In 1962 an implant with a completely different de-sign compared to the previous ones was presented,and it exploited the immediate stability and resist-ance of divergent needles, inserted deeply into thecompact bone. Each needle, placed directly into the

bone through the mucosa, could easily be pulledout (Figs. 1, 2), but after external blockage the nee-dles became a single unit that could withstand ex-traction and showed exceptional stability. Theemerging portion of the needles, bent and broughtclose to each other with a pair of pliers, were lockedtogether with self-curing resin, forming a singleblock, and they were then shaped to form an abut-ment. The divergence of the needle also had the ad-vantage of distributing the occlusal load across avery broad support (Fig. 3). This technique was de-signed by the Frenchman Jacques Scialom, whonamed it “technique des implants aiguilles” (nowknown as the Scialom needle or pin implant tech-nique) (1-6). The needles were made of tantalum, arelatively “new” metal that is pure, acid- and base-proof, and totally biocompatible1 (Figs. 4–7).In 1970 Piero Mondani replaced the basic metalused for the implants with titanium, due to itsgreater ductility for implant purposes (Fig. 8) (7–9).

IMPLANTS OF THE 1960s

Part I

Fig. 1 Mandrel mounted on a micromotor for needle insertion in thebone tissue according to Scialom’s technique (1962).Fig. 2 Tantalum needle engaged with the corresponding mandrel.

Fig. 3 Bernkopf’s scheme for the study of load distributionover divergent needles (1970).

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Drawn titanium is highly stress-resistant, so thatwhen three or four needles are inserted with differ-ent divergent angles and are united externally intoa single block, they are:1) virtually impossible to remove;2) able to bear a high load stress (10).The needles have a flattened lancet tip to ease bonepenetration by rotation; at the opposite end twosmall tabs permit their engagement with a series ofthree mandrels fitted with a coupling for a low-speed contra-angle. The tabs slide into the grooves of the first mandrelfor nearly its entire length, in order to hold the nee-dle in place while avoiding tip oscillation when it isrotated. Following needle insertion into the boneup to the end of the first mandrel, the latter is re-placed by a second mandrel, which allows furtherpenetration without displacing the needle tip, con-tained by the bone walls at this point. The thirdmandrel has two very short lateral grooves and per-mits further minor penetration of the needle intothe cortical bone. The Scialom kit also came withsteel drills (no. 8, 10 and 12 Torpan drills) for oc-clusal compact bone perforation in the event ofhigh resistance to needle-tip penetration. The practical demonstrations on patients were per-formed by very expert operators, whom Scialomhad personally selected from all over Europe andtrained. The surgery appeared to be extremely easyto perform due to the almost complete absence ofbleeding and pain, which was easily managed withjust a few drops of local anesthetic. The absence ofpostoperative pain and the possibility of immediateloading with temporary prostheses made the con-cept even more interesting to the “audience.” Theneedle implant was used extensively in the 1960sand 1970s, but was misinterpreted because it wasconsidered easy to perform. Nothing could be fur-ther from the truth—and we feel this is essential tonote—because it is actually the most complex anddifficult implant to place. The technique cannot belearned in a two- or three-day course, as in the case

of other types of implants. It requires physicians who are extremely well-versed in implantology, anatomy, biology, biometal-lurgy and physics; its philosophy, design, andrules—dictated by construction engineering—must be mastered fully. It requires specialists whoare willing to devote a great deal of time to learningthe technique of an implant passing through boneareas inaccessible to other implants that differ inform. Indeed, in the event of failure, the implantcan be removed without leaving any residual bonelesions. The needle implant technique was shrewdly adver-

Implants of the 1960s IV

1 Tantalum (from Greek mythology, after Tantalus; punished for his offenses against the gods, in Hades he was condemned to be within reach of food andwater he could not eat or drink, as an eternal reminder of his crime) was discovered in Sweden by Anders Ekeberg in 1802 and isolated by Jöns Berzeliusin 1820. Atomic symbol Ta, number 73 of the Mendeleev table; its atomic weight is 180.95 amu. Tantalum largely occurs in the minerals tantalite [(Fe,Mn) Ta2O6] and euxenite,and its deposits can be found in Australia,Brazil,Canada, the Democratic Republic of the Congo,Mozambique,Nigeria,Portugaland Thailand.At first it was used as filament in electric light bulbs, but was soon replaced by tungsten. For industrial applications it is still used to makestructures that come in contact with liquids and corrosive gases, and as essential component of rectifying electrodes. It is highly corrosion-resistant: Attemperatures below 150°C it can be considered totally immune to chemical attack, and can be dissolved only by hydrofluoric acid. In medicine it isemployed as suture thread in neurosurgery, as a component of orthopedic screws and plaques, and, as described, in implant dentistry. Its melting pointis 3017° C (5463° F), and it is very expensive to produce.

Fig. 8 Titanium needle (Mondani, 1970).

Figs. 4, 5 Examples of tantalum needles. Fig. 6 Anatomicalspecimen showing the mandibular nerve course that, with the Scialom

needle technique, can be avoided without causing any damage.Fig. 7 Example of 4 needles bearing a bridge for 4 years (1967–71).

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tised. Equipment sales became big business, sincethe professionals who witnessed the surgeries(which seemed very simple to perform) rushed tobuy the kit, sold solely to those who attended thedemonstrations. It must be noted that, if performedcorrectly, the needle implants permitted (and stilldo!) the quick replacement and rehabilitation of

both single-tooth and complete edentulism, even inthe frequent cases that were not eligible for thetherapeutic measures offered by other oral implanttechniques. The tripods often allowed placement ofthe needles even in areas mesial and distal to themaxillary sinus (Fig. 9), and—incurring a low lev-el of risk—also in resorbed mandibular ridges. Inthis case, through their skill and anatomical knowl-edge the demonstrators were often able to avoid theinferior alveolar nerve by placing the needles later-ally. Surgery was performed using a few drops of lo-cal anesthetic, sufficient for pain management with-out blocking the sensibility of the nerve, which im-mediately reacted to any accidental contact with theneedle tip, warning the operator to move the nee-dle before proceeding with apical insertion. With the exception of a few cases, complicated byresidual (and serious) permanent labial anesthesia,accidental nerve lesions healed within a time frameranging from a few days to a few months.2 In an-other section of the book we will see how thesecomplications can be avoided by means of radi-ographic tests (CT) (Figs. 10–31).

Fig. 9 Upper tripod, which permits exploitation of severelyatrophic bone areas.

Fig. 10 Severely atropic mandible. Fig. 11 Orthopanthomography of the case (1985). Fig. 12 Mucoperiosteal flap opening.Fig. 13 The thin superficial fibrotic layer is removed with the scalpel blade. Fig. 14 The occlusal bone surface is smoothed with a

surgical drill. Fig. 15 Upon further flap detachment the alveolar nerve exiting the mental foramen can be observed. Nerve visualizationpermits safer insertion of the needle-type implant. Fig. 16 The set of needles that will be employed for this case, with a diameter

ranging from 1.2 to 1.5 mm. Fig. 17 The first correctly inserted needle avoids the nerve and reaches the inner cortical bone.Fig. 18 Placement of the second needle and mandrel view. Figs. 19, 20 Placement of other needles and illustration

of their divergent axis, on the right.

2 The literature describes cases of extended loss of nerve sensibility that returned even one or two years later.3 See Chapter 9 on the intraoral solder.

9

10 11 12 13

14 15 16 17

18 19 20

Famous demonstrators of the time included Anto-nio Tamburo Di Bella and Pierluigi Mondani. Con-cerning the latter, later in this book we will discusshis intraoral electric solder, which replaced self-cur-ing resins and improved needle blockage, permit-ting immediate welding of the abutments in a sin-gle and highly resistant splint.3

Before inventing the intraoral solder Mondani useda clever muretto (literally, a “small barrier” consist-ing of two perforated plaques of soft metal), inwhich he inserted and blocked the abutments withself-curing resin. The temporary or definitive pros-thesis, either fixed or removable, could be cement-ed over the muretto. Not all the buyers of the Scialom toolkit had their“eyes on the needle tips” like their instructors, nordid they have the necessary tactile sensitivity to per-

ceive the transition between cancellous and com-pact bone tissue, where the needle progression hadto halt. The Scialom implant—intelligent, simpleand durable—was thus mistrusted by many whowere unable to use it correctly or load it with oc-clusally balanced prostheses.

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Fig. 21 Atrophy of the contralateral side (right) shows the sole presence of compact bone with very little vascularization.Fig. 22 Placement of other needles. In this case, the diameter of the edentulous ridge allowed employment of titanium needles varying

in diameter from 1.2 to 1.5 mm. Fig. 23 The temporary prosthesis cemented right after surgery allows the normal feeding of the patient.This picture was taken 10 days after surgery because the previous image showing the suture was lost (1985).

Fig. 24 View of the prosthetic abutments after temporary prosthesis removal, and appearance of the mucosa without preventive hygiene.The abutments were welded using Mondani’s intraoral solder. Fig. 25 Clinical pre-implant aspect and definitive prosthesis in gold resin

placed on the implants. Fig. 26 Radiographic and occlusal checkups (1985).

Fig. 27 The smile. Fig. 28 The same mouth 15 years later (1985–2000). Note the mild horizontal atrophy, more accentuated on theright side; nevertheless, the prosthesis is stable and functional, and the mucosal aspect is satisfactory.

Fig. 29 Radiographic validation (1985–2000).

Figs. 30, 31 The CT scan shows the complete osseointegration ofthese needles after 15 years of service.

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Bernkopf came up with ingenious alternative solu-tions to the external resin blocks, which permittedthe manufacture of prostheses that were more hy-gienic and not as coarse (11, 12). The needles couldbe used as tripods or quadripods (Bernkopf’s are anexample of this) or also, when working with nar-row mandibles, as simple—but strong—bipods.

RemarksOne of the criticisms of the technique describedhere arose from the observation of totally unsani-tary prostheses that were impossible to clean oncethey were cemented over the needles.Le patologie occlusali. Eziopatogenesi e terapia

clarified that the exposed trifurcations and bifurca-tions of natural teeth with periodontal disease arenot a consequence of sepsis but, rather, of the lackof occlusal balance. We take full responsibility forstating that periodic cleaning of the bi- and trifur-cations by means of scaling and root planing, with-out removing the static and/or dynamic prematurecontacts that traumatize them, will merely yieldroots that are perfectly clean when they are ex-pelled.Nevertheless, this does not diminish the impor-tance of the hygienic principles that every profes-sional must respect in prosthetic rehabilitation. Theability to maintain a good hygiene level under thepontic of fixed prostheses is one of the prerequisites

distinguishing a good prosthodontist from an in-competent one, and a clean mouth from an un-pleasant one.Unfortunately, certain prostheses placed on needleimplants cannot always comply with these princi-ples, even when—with a little patience, good will,foresight and disregard for financial gain—theycould be manufactured showing greater respect forthe most elementary hygienic rules. When one ofthese prostheses became uncemented, we wereforced to remove it due to the debris that had accu-mulated beneath it over the course of fifteen years(and, frankly, it was repugnant). The reader can check the clinical observation of thestate of the mucosa surrounding the abutments(Figs. 32–37) in photo 34, taken after prosthesis re-moval (and a much-needed rinse!), whereas the ex-cellent state of the implants can be noted in Fig. 35. Chapter 9 is devoted to describing Mondani’s intra-oral solder and how it is used, and illustrating theenormous benefits that it contributed to this andmany others implant techniques. We must conclude this chapter by disenchantingthe reader as to the apparent surgical simplicity ofScialom’s needle technique. The simple purchase ofthe needle and mandrels required for their insertioncannot possibly impart the sudden ability to per-form these procedures.This surgery is unquestionably the least bloody and

Fig. 32 A natural abutment and 4 needles supporting a four-crown bridge (Mondani, 1981).Fig. 33 The gold-resin bridge. Fig. 34 Bridge removal after 15 years (1981–96). Note the inert resin used for preparing the long

abutment and the debris (with marginal gingivitis), which nevertheless did not compromise implant stability.Fig. 35 Rehabilitation of the same case with other types of implant, but exploiting the needles inserted by Mondani in 1981, checked

regularly for 25 years (1981–2006). Figs. 36, 37 Prosthesis appearance (gold-porcelain), and close-up of the mucosa and the crownmargins over the implants (2006).

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35 36 37

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painful of the many that are currently available.Furthermore, if performed well it always permitsplacement of a stable temporary prosthesis, whichimmediately gives the patient the pleasure and ben-efits of correct masticatory function. That said, de-veloping the ability to keep one’s “eyes on the nee-dle tips” requires long apprenticeship, and patientteaching by a long-time expert in order to masterthe technique, not only for the traditional Scialommethod but also as an aid for other implant solu-tions.

References

1. SCIALOM J. A new look at implants: a fortunate disco-very: needle implant. L’Information Dentaire 1962March;44:737-742.2. SCIALOM J. Rappel scientifique et tecnique sur les im-plants aiguilles. Implants Aiguilles 1963 Oct.3. SCIALOM J. Needle implants. L’Information Dentaire1962;44:1606-11.4. SCIALOM J. La Belle fixe et les risques d’infiltration.Evolution Odontoimplant 1963;1(3):7-10.

5. SCIALOM J. Etre ou non être pas implantologiste. RevOdontoimplant 1969;1:3.6. SCIALOM J. Editorial. Rev Odontoimplant 1968;4:10.7. MONDANI P.L., MONDANI P.M. Parestesie del nervomandibolare da impianti. Riv Odontostomatol Implanto-protesi 1987;8.8. MONDANI P.L., MONDANI P.M. Il Titanio. Elle/BiDental materials Feb 1989.9. MONDANI P.L., MONDANI P.M. Aghi e TC. Riv Odon-tostomatol Implantoprotesi 1991;1.10. LORENZON G., BIGLIARDI C., ZANETTI E.M., PER-TUGIO R. Analisi biomeccanica dei sistemi implantari.Dent Cadmos 2003;10:63-86.11. BERNKOPF A. L’impianto alloplastico nella praticaambulatoriale. Considerazioni generali: radiografia e stra-tigrafia - falso moncone fuso individuale scomponibile.Metodo personale. Comunicazione al VII Seminaire desImplants Aiguilles. 1970.12. BERNKOPF A. Lettera aperta al Collega Paoleschi. As-sociazione Italiana Impianti Alloplastici 1971;1:31.

Figs. 3, 7 and 9 Courtesy of Dr. A. Bernkopf.


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TREATISE OF IMPLANT DENTISTRY CHAPTER IV - Part IIin collaboration with Silvano Tramonte

J ust one look at the implant presented by Ste-fano Tramonte in 1964 (1) and it is imme-diately clear that it differs enormously from

all the previous screws (Fig. 1), for with that screwtitanium began to be employed in implantology.1

This is another merit of Stefano Tramonte, whopaved the way for all subsequent implants by in-troducing this new material. This authorship mustbe acknowledged, given that thirty years laterothers would attribute it to the Swedish school(2)!In 1959 Tramonte initially used screws made ofchromium-cobalt (3, 4) (Fig. 2), designed with astreamlined profile and sharper threads than theones that had been tested by the Strock brotherstwo decades earlier (5), and that Gola proposed

again, also in 1959 (6).In this regard Tramonte wrote:

Considering that casting techniques were not as so-phisticated as they are today, my chromium-cobaltscrews were very unrefined and had to be finished byhand: sprue pin cutting, bubble removal, polishingand sharpening of the threads. Since chromium-cobalt is an extremely hard alloy, it took about twohours to finish each screw! Therefore, I decided notto use that material, even though it showed great bio-compatibility, and switched to surgical steel, whichcould be machined. . . . Towards the end of 1964 Ibegan to manufacture my screws in titanium and pro-posed the use of this material in implantology for thefirst time in the world (7) (Figs. 3, 4).

STEFANO TRAMONTE’S DRIVE SCREW

Part II

1 The previous chapters noted that Cherchève, Muratori and Linkowalso employed titanium.Although their implants have been cited herefor informative purposes, since they derived directly from theFormiggini spiral, on a historical level they came after Tramonte’stitanium screws.

Fig. 1 The Tramonte screw, made of titanium since 1964.Fig. 2 The first chromium-cobalt screws.

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Fig. 3 A titaniumscrew (left; T), and thecorresponding screw inchromium-cobalt(right; A).Fig. 4 A completeset of Tramonte screwswith a 5-mm diameter,ranging from 2 to 7threads.

Tramonte and Ugo Pasqualini had been school-mates and friends for years. As a result, Pasquali-ni was immediately informed of the interestingopportunities offered by the new titanium screws,illustrated by Tramonte himself when he placedthree demonstrative implants at his friend’s prac-tice in two of the latter’s patients. Pasqualini had completed his research on dogsthree years earlier, demonstrating that vented im-plants made of biocompatible material (and withshort emerging posts) became perfectly osseointe-grated, exactly like the completely buried im-plants with internal threading (8). Since it took sixmonths before the prosthetic abutment could bereplaced, he was very interested in Tramonte’sscrews, which—directly inserted into the bonethrough the mucosa—were immediately stable.Compared to Pasqualini’s two-step implants, theadvantages offered by the “automotive” screws, astheir inventor jokingly referred to them, seemed

enormous. Fitted with a solid prosthetic abut-ment, which extended into a sturdy shaft withsharp cylindrical helical threads, they could im-mediately be loaded without waiting for completereparative osteogenesis.Tramonte’s idea was to increase the implant’s sta-bility by self-tapping the screw into bone tunnelswith a reduced diameter, exploiting the “screw-unscrew” movements transmitted by a specialhand ratchet. To facilitate implant insertion, heinitially used a round drill; passing through themucosa, the drill perforated the bone up to the de-sired depth and was followed by a round drill witha larger diameter, in order to enlarge the boreslightly and then insert the screw (Fig. 5). In spite of the extraordinary initial stability andgood metallic sound at percussion, nearly all ofthe screws were expelled after a month of terriblepain. Anyone else would have given up, but notTramonte who, despite the numerous failures, didnot underestimate the few absolutely painless cas-es that demonstrated the permanent stability ofhis screws. Of the three implant surgeries per-formed at Pasqualini’s practice, two were destinedfor utter failure, whereas the third one, withoutany postoperative pain and placed in the samehemimandible where the adjoining implant hadbeen expelled (Figs. 6–8), could be used as sup-port for a bridge and worked for more than twen-ty years, until the patient’s death.In the second patient the failure occurred in thesame time frame (one month), with painful expul-sion of the screw, which had been loaded immedi-

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Stefano Tramonte’s drive screw IV

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Fig. 5 The first round drills and hand ratchets for placementof chromium-cobalt screws.

Fig. 6 Three implants immediately after placement. Fig. 7 At four weeks, expulsion of two of the three implants, with severe bone lossaround one of them due to compression ischemia, necrosis and subsequent bone resorption.

Fig. 8 The third implant, in service for more than 20 years (1966–87). Note the bone apposition around the threads, and the mild conicalresorption around the neck.

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ately. The pain was excruciating. The intraoral ra-diographies showed that around the screw therewas a bone layer that was separate from the sur-rounding tissue. The bone had adhered to the ex-planted screw and had to be unscrewed from it.The two bone fragments, split using a carborun-dum disk, preserved the thread marks. The histo-logical examination confirmed that the bone re-sorption area consisted of a fibrous layer in disar-ray and bone tissue in hyaline-like degeneration(Figs. 9–12). Given that the chromium-cobaltused for the screw was unquestionably a biocom-patible material, the cause of failure was attributedto excessive compression during screw insertion.Today, however, we know that the mistake wasimproper surgical technique, due not to excessivebone compression but to screwing the implant intoo much, which caused what Pasqualini definedyears later as a “corkscrew effect.” When the screwtip reaches the bottom of the surgical insertionsocket and resistance to penetration exceeds thebone fracture limit, the implant rotates withoutpenetrating, and the bone within the threads is lit-erally torn out in a coronal direction, remainingamong the threads when the implant is removed(Fig. 13). Nevertheless, the few successes that wereachieved—among the failures of identical screwsthat “fell like autumn leaves”2—suggested to theauthor that there were also positive qualities thathad yet to be detected. In an attempt to pinpoint the defect, Tramontecontinued to perform implant surgeries free ofcharge, until he ascertained that failure was not as-cribable to the implant itself but to the surgicaltechnique: It was essential to avoid compressingthe bone too much or “ripping it out” by forcedscrewing. Success was achieved only when the screws were

2 Tramonte’s joking remark.

Fig. 9 Another surgical failure. Fig. 10 Implant avulsion after cutting of the Richmond crown on the second premolar.Fig. 11 Histological specimen of the bone loss area before analysis. Fig. 12 Histological analysis confirms the presence of a fibrous

layer in disarray and bone tissue in hyaline-like degeneration (1966).

Fig. 13 A screw in the expulsive phase due to the “corkscreweffect.”Fig. 14 Left: a lance drill. Right: a calibrated helical drill.

Fig. 15 Detail of the helical drill.Fig. 16 The steel tapper.

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13 14

15 16

placed in larger bone tunnels, but were also tightenough to stabilize them without excessive com-pression. He then got rid of the inaccurate rounddrills, and replaced them with a three-facetedlance drill, followed by a second calibrated helicaldrill (Fig. 14). Using the first one, similar to thetype proposed by Muratori, he performed the ini-tial perforation of the mucosa and underlyingbone. He wrote, “Its pointed tip prevents slippingon the ridge surface, avoiding the risk of falseroutes in both the labial and buccal fibromucosa”(9–12).The tunnel was then widened with the helical drill(Fig. 15), which in addition to preparing the prop-er diameter site for implant insertion, also re-moved the bone chips along the grooves, furtherfreeing the space for the screw. The round drillcreated the perforation by crushing the bone tis-sue, most of which was left inside the hole and ob-structed its lumen. The third modification was theaddition of a steel drill with conical spirals (Fig.16) that had the same screw pitch as the cylindri-cal spirals of the titanium screws, which easedscrew progression. The steel drill is known as a tapper, but the termis incorrect: tappers pave the way for the screwsby removing bone, whereas Tramonte’s device fa-cilitates progression by means of a primary inci-sion, without removing tissue from the tunnelwalls. Therefore, this aspect sets it apart both fromindustrial tappers and from any other tapper usedto prepare the site for every type of implant screw. The tapper carves the compact cortical bone likea knife, cutting it with spirals of progressive diam-eters from 0 to 4–5 mm, corresponding to the di-ameters of the first and last titanium screwsthreads, respectively. Therefore, it carves its coni-cal profile into the tunnel, which is later complet-ed by the final cuts made with the self-tappingscrew threads, giving the implant enormous sta-bility that permits immediate loading. The tech-nique required the use of four steel tappers, re-spectively with three, four, five and six threads,which could be used—according to the instruc-tions—for all titanium screws (Figs. 17, 18) Over-all, the sequence of instruments was very logicaland fast, and permitted easy screw placement(Figs. 19–21).Tramonte’s drive screw is one of the most impor-tant dental implant concepts of the 1960s, and itis still valid today (Figs. 22, 23) (13). The complete toolkit now comprises two lancetdrills and a set of calibrated drills for the variousimplant sizes, Grade 5 titanium tappers for screwsfor diameters 4 and 5, a set of ratchet keys for the

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Fig. 17 In the middle, the tapper (2), whose progressive threadspenetrate the bone tissue precisely, paving the way for subsequentinsertion of the screw with cylindrical threads (on the right) (3).Fig. 18 Sets of tappers with different numbers of threads.

Figs. 19, 20 Example of tapper insertion followed by thescrew. In Fig. 20, on the right side note the precise cut made bythe tapper threads into the bone tunnel.Fig. 21 Suture and loading of the previously illustrated case.

17 18

19

20

21

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two different abutment sizes, the jack and a com-plete set of accessories. The implants in the catalogue have a diameterranging from 2.5 to 6 mm, and standard lengthsbetween 11.5 mm and 22.75 mm, but implants asshort as 4 mm can be requested if needed. Thereare implants with threads for ball attachments foroverdentures, implants with neck lengths reducedfrom 5 to 3 mm, and implants with cores enlargedto 3.1 and 3.5 mm (the standard diameter is 2.25mm). The author suggests using the bigger screws fromthe second series to replace a mobilized “normal”screw. In this case, removal of the latter will besufficient, followed by replacement with a screwwith a larger diameter a few days later. This last in-dication represents an implant innovation that thedental world owes exclusively to Stefano Tra-monte (14).

Notes on surgical techniqueFollowing anesthesia, and after drying and clean-ing the surgical field, the pilot drill, mounted on aspeed-reducing contra-angle handpiece, is forcedthrough the mucosa until it comes into contactwith the cortical bone (Figs. 24, 25). At this pointthe handpiece is operated with the specific micro-motor at the appropriate speed to allow the drilltip to penetrate the cortical bone with the entirecutting portion of the drill (Fig. 26, 27). The purpose of the pilot lance drill is to prepare aprecise opening for the calibrated drill, which isdesigned to create the surgical tunnel. Upon com-pletion of the first perforation, the calibrateddrill—whose length corresponds to the selectedimplant—is mounted on a micromotor (note thatthe drill is 1 mm longer than each implant size, inorder to create a “safety” chamber). In the mostfrequent cases of flapless surgery, which do notpermit a precise landmark for calculating the in-sertion depth, this type of device allows for aslightly deeper bone tunnel, which minimizes therisk of tissue lesions caused by overscrewing(“corkscrew effect”). Consequently, all measure-ments of the distance between the ridge and themandibular alveolar nerve should be made in re-lation to drill length rather than the length of theimplant. The surgical socket is finalized by perfo-rating the bone to the required depth (Figs.28–31), up to the point where the handpiece headslightly compresses the mucosa. The axis of the implant, and thus the direction ofperforation, should correspond to the axis ofgreatest bone thickness. The primary aim is opti-mal positioning of the implants, and not that the

Fig. 22 Beautifulhistological appearanceof a Tramonte screw tip,fractured after years ofservice and perfectlyosseointegrated with thebone tissue (toluidineblue).

Fig. 23 Screw threadand bone tissue, with nogaps between them.Theblock section histologicalspecimen taken afterseveral years offunctional service(toluidine blue).

Figs. 24, 25 Beginning of flapless penetration with lance drill.

Figs. 26, 27 Further deepening with the same drill.

23

22

24 25

26 27

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implant abutments should immediately be paral-lel (Fig. 32). Following removal of the calibrated drill, the tap-per is mounted on the finger key, or the ratchetwrench in the event of difficult insertion, andscrewed into the socket until bone resistance canbe felt (Fig. 33, 34). As the finger key no longer exerts the requireddriving force at this point, it must be replaced bythe knob key. In cases where tapping with theratchet wrench is needed, it is advisable to switchto the knob key or the standard key as soon aspossible, since use of the ratchet wrench duringthis step is not safe and does not permit promptunscrewing in case of emergency.When the tapper has been placed firmly in thebone, the knob key is replaced by the standardone, which exerts greater driving force and per-mits the safe alternating movement of screwing-unscrewing, or sudden reverse movement if nec-essary. If the presence of natural teeth or abut-ments interferes with the procedure, the specialextension provided can be mounted on the stan-dard key. The tapper, now manufactured in Grade5 titanium, serves manifold purposes.1) It creates female threads in the walls of the sur-

gical socket made with the calibrated drill,profitably reducing implant insertion force,since the Ti2 screw does not have high resist-ance to torsion.

2) The tapper, which is conical, is easy to place inthe surgical bore, creating conical counterthreading with the base of the cone towards thealveolar ridge. The base width (represented bythe last thread of the tapper) corresponds to theimplant diameter. Thanks to this design, thefirst implant spiral will be engaged in progres-sively narrower bone, threading it as it pro-ceeds apically, and this permits self-tappingwhen needed in order to achieve the optimalprimary stability;

3) Use of the tapper enables testing and measure-ments, so that the subsequent implant inser-tion will be of the greatest precision in relationto available bone tissue, while maintaining amargin of safety from important anatomicalstructures. This is a fundamental principle ofthe Tramonte’s technique. The implant width ischosen based on the bone density of the futureimplant site, taking the Misch scale into ac-count, so that implants with a diameter of2.3–3 mm diameter will be inserted into D1bone, implants with a diameter of 3–3.5 mminto D2, 4-mm implants into D3 and 5-mm im-plants into D4.


Figs. 28, 29 Use of the calibrated drill to create the surgicaltunnel.Figs. 30, 31 Another step in the procedure.

Figs. 33, 34 Use of the Tramonte tapper.

28 29

30 31

33 34

Fig. 32 The implant axis must correspond to the axis of greatestavailable bone thickness,without worrying about parallel placement.

32


The tapper is then withdrawn once the threadingof the surgical socket is complete, and the proce-dure is repeated with the selected implant—with-out applying excessive force to the socket walls—until it is fully set in its site. Both the tapping procedure and implant place-ment involve certain risks. In very spongy bonethe danger lies in overscrewing, leading to partialor total fracture of the bone portions containedwithin the threads. Overheating, and locking andfracture of the implants are instead the risks thatare run with compact bone, caused by the frictiondeveloped between the threads and the bone dur-ing implant advancement, especially when largerscrews are involved.The parallel position of the abutments cannot beaddressed until the implants have been posi-tioned. With the Tramonte screws, this can bedone by bending the abutment using a standardkey or a pair of pliers, and/or with the aid of tung-sten carbide bur mounted on a high-speed hand-piece, with abundant water cooling. A temporarycrown is then mounted immediately3 (Fig. 44).The temporary prosthesis can be replaced by a de-finitive one about 60–90 days later.

Observations and conclusionsTramonte did not perfect his technique through

divine inspiration. In the interval between thevery humble presentation of his drive screw andits current success—which rightly places himamong the pioneers of implantology as the inven-tor of one of the most intelligent, simple and sta-ble implant concepts—he suffered humiliationand faced sarcasm, but he never doubted that his

3 Counterbending of the abutment should be avoided because titaniumcannot withstand this type of stress, and subsequently undergoesfracture.

35

43 44

36 37

4039 41 42

Figs. 35-42 The screw is placed in the surgical socket (note the yellow antibiotic ointment); parallelism with the contiguous teeth isachieved by filing the implant abutment with a tungsten carbide bur and water jet cooling. This technique, which has been used for many years,

has never created any problems for titanium’s inherent structure.

Fig. 43 Radiographic checkup following surgery.Fig. 44 Immediate temporary crown.

Fig. 45 Checking with a bone caliper, which is indispensablefor the flapless technique.

45

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38

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Figs. 49, 50 Edentulism of the left lower quadrant treatedwith three Tramonte screws and a gold-porcelain bridge (1981).

49

50

Fig. 51 Replacement of a molar with a three-thread Tramontescrew.The flapless technique was used.

51

Fig. 52 The primary stability of this implant can withstand thetension of five orthodontic elastics.

Figs. 53, 54 Case treated with a single gold-porcelaincrown.The arrows indicate the complete osseointegration ofthis immediate-load implant.

52

53

54

Figs. 46-48 The impact of the screw threads on an area ofcompact bone can divert the ideal screw insertion pathoutside the surgical tunnel, leading to necrosis, ischemia andresorption of the compressed bone tissue, which willsubsequently be expelled with the implant (Fig. 48) and causeexcruciating pain.

46

47 48

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implant would gain the recognition it deserved(15–19). Tramonte’s screws, like all implants, are not entire-ly risk-free. One of their limitations, albeit a rela-tive one that is easy to surmount, is a consequenceof the fact that they can be inserted into the bonedirectly through the soft tissue, with a rapid andalmost bloodless surgical procedure. This meansthat surgery must be performed on suitably largealveolar ridges free of undercuts. In case of doubtor based on personal preference, the operator candetach the mucosa for direct vision of the under-lying bone. The flapless approach is not compul-sory for this protocol, but represents a variant ofthe traditional technique, and the surgeon shouldevaluate its use carefully while planning the pro-cedure. Tramonte also added an ingenious bonecaliper to his toolkit (now available from all sup-pliers), which permits good assessment of any un-dercuts even during closed surgery (Fig. 45).The last risk connected with the use of a self-tap-ping screw—fortunately quite rare but also themost serious—is the monolateral impact of thescrew threads with an area of compact bone. Thiscan potentially divert the screw insertion pathoutside the surgical tunnel, leading to necrosis, is-chemia and resorption of the compressed bone tis-sue, which will subsequently be expelled with theimplant itself (Figs. 46–48). An attentive operatorwill always perceive displacement of the screwand, being aware of the consequences, he/shemust immediately remove it and modify the tun-nel path, choose another implant site or replacethe cylindrical screw with a conical implant. In any event, self-tapping screws offer:1) virtually bloodless surgery, which can often be

performed with a flapless approach;2) immediate stability, permitting immediate load-

ing with a temporary prosthesis and then a de-finitive one, without waiting for later stabiliza-tion by reparative osteogenesis;

3) high resistance to occlusal loads, counterbal-anced by the long lever arm of the implant aswell as stress dispersion along the wide hori-zontal planes of the threads;

4) a longer control period than any other currentimplant, since Tramonte’s screws have beenused successfully by hundreds of professionalsfor more than four decades (Fig. 49–54).

References

1. TRAMONTE S.M. L’impianto endoosseo a vite autofilettan-te. Trent’anni di esperienza personale. Milano: Editrice Co-

minplant;1991.2. IGLESIAS J.G. La epoca heroica de la implantologia enEspana. Los pioneros. Madrid: Ed. SEI; 1997. p. 136.3. TRAMONTE S.M. Un nuovo metodo d’impianto endoos-seo. Proceedings of the 5th National SIOCMS CongressSIOCMS; Naples, Italy. 1962.4. TRAMONTE S.M. L’impianto endoosseo razionale. Milano:Ed. Lusy; 1964.5. STROCK A.E., STROCK M.S. Experimental work on a me-thod for the replacement of missing teeth by the direct im-plantation of a metal support into the alveolus. Am J OrthodOral Surg 1939;25:467.6. GOLA L. Impianti alloplastici endoossei ammortizzati. Pro-ceeding of the 2nd Symposium on Alloplastic Implants; Pavia,Italy. 1959.7. TRAMONTE S.M. Intrabone implants with drive screws. JOral Impl Traspl Surg 1965;4:126.8. PASQUALINI U. Reperti anatomo-patologici e deduzioniclinico-chirurgiche di 91 impianti alloplastici in 28 animali daesperimento. Riv Ital Stomatol 1963;3-98.9. TRAMONTE S.M. A further report on intraosseus implantswith improved drive screws. J Oral Impl Transp Surg1966;9:78.10. TRAMONTE S.M. Implantologie endo-osseuse: préjugéeset craintes. L’Information Dentaire 1966;8:148.11. TRAMONTE S.M. Su alcuni casi particolarmente interes-santi d’impianto endoosseo con vite autofilettante. Ann Stom1966;15(4):320.12. TRAMONTE S.M. L’impianto a vite autofilettante. Riv ItImplant 1966;1:95.13. BIANCHI A., SANFILIPPO F., ZAFFE D. Implantologia eimplantoprotesi. Basi biologiche. Biomeccanica. Applicazionicliniche. Torino: UTET; 1999. p.159-257.14. Tramonte S.M. Intraosseous self-threading implantations.Personal method. Dent Cadmos 1971 Feb;39(2):192-208. 15. CAMERA A., PASQUALINI U. Impianti endoossei: istolo-gia comparata della “zona del colletto” in un dente naturale,due monconi di Linkow e tre viti di Tramonte. AssociazioneItaliana Impianti Alloplastici 1972;3.16. TRAMONTE S.M L’impianto a vite autofilettante nella so-stituzione di un solo dente mancante. Riv Eur Implant1978;4:15-21.17. TRAMONTE S.M. A proposito di una modificazione sugliimpianti alloplastici. Rass Trim Odont 1963;44(2)129:36.18. TRAMONTE S.M. L’impianto endoosseo a vite a carico im-mediato. Proceedings of the 27th GISI International Meetingon Dental Implants and Transplants. Bologna, Italy: 1997. p.71.19. TRAMONTE S.M. Vite endoossea autofilettante. AttualitàDentale 1989;7:44-9.

Figs. 22, 23 Courtesy of Andrea Bianchi, Francesco Sanfilippo andDavide Zaffe. From Implantologia e Implantoprotesi. Turin: UTET,1999. Figs. 24–45 Courtesy of Silvano Tramonte.

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CHAPTER IV - Part IIIin collaboration with Silvano Tramonte

I n 1972 Antonio Camera, who at the time wasdirector of the Clinical and Histology and Ana-tomopathology Research Department of the G.

Ronzoni Medical Surgical Institute in Milan, UgoPasqualini, who was professor of MaxillofacialSurgery and Prosthodontics at the University ofModena, and Stefano M. Tramonte, inventor andpatentee of the drive screw (1–14) and also thefirst to employ titanium in implant dentistry (15,16), published a study that is still unique today:the comparative histological study of the tissuesforming the epithelial seal at the implant and na-tural tooth emerging area (17). The study, published 36 years ago, addressed allthe questions of the era regarding the hazards ofhypothetical intra- and extra-tissutal communica-tion and the creation of a surrogate epithelial at-tachment in place of the natural one. Neverthe-less, the research went far beyond this, althoughit was not given proper recognition at the time. Itconfirmed—decades in advance—the absoluteneed for a biological space to assure a complete-ly safe relationship between implant structures

and biological tissues, i.e. avoiding peri-implantbone resorption, which is not physiological butmust be considered a true iatrogenic outcome.The Tramonte implant was designed in 1959 forthe specific purpose of immediate loading. It be-gan to be manufactured in titanium in 1963 andhad a biological width area, as a result of which itaroused hostility and misunderstanding withinthe academic and scientific world. Nevertheless,it anticipated—by decades—the principles thatare now are recognized as the most scientificallyadvanced: immediate loading, flapless insertion,biological width, single-phase execution, ad-vanced design of the endosseous core and bettercompliance with the theoretically ideal shape,Lemons’s plateau (18) from a biomechanicalstandpoint, and a smaller emerging portion of theimplant in order to protect the biological seal(19). In 2005 Camera, working with Marco E.Pasqualini and Silvano Tramonte, reviewed theimpressive work published 33 years earlier andconducted a critical analysis. The patient from1970 required placement of a Linkow blade im-plant (20) in the lower right distal area, as the sitewas unfit for a one-step implant due to severehorizontal bone resorption. Three years earlier, a gold-resin bridge had beenplaced in the upper arch over three Tramonte self-threading screws and three natural abutments(Fig. 1). Before placement of the blade implant(1970), the bridge was removed in order to checkthe status of the three upper screw implants,which appeared to be stable and were surround-ed by a healthy mucosa. Periodontal probingaround the neck of each implant assessed pocketdepth (2 to 3 mm) and the onset of classic com-pression ischemia could be noted. The blade-im-plant surgery was performed on October 26,

COMPARATIVE HISTOLOGY OF THE NECK AREA OF A NATURAL TOOTH AND THREE TRAMONTE SCREWS

Part III

1

Fig. 1 Preoperative panoramic X-ray.


1970 (Fig. 2).Six months later (1971) the patient returned be-cause the upper bridge had become decemented.During the medical examination, she agreed toundergo a biopsy sampling around the Tramontescrews, which were very stable (Fig. 3), and alower tooth affected by periodontal disease (Fig.4). With the patient’s consent, the surgical flap in-cision made for the sampling was extended distal-ly, which made it possible to observe the perfectosseointegration of the blade (Fig. 5). After pros-thesis cementation, a comparative histological as-sessment was performed.

Aim of the researchThe researchers’ aim in 1971 was to analyze andverify the behavior of the mucosa and the under-lying corium at the level of the epithelial attach-ment surrounding the emergence profile of theTramonte implant fixture. What we intend to dotoday—in addition to reproposing a study that isstill current and valuable in a field in which fewstudies have been conducted (21–38)—is to as-sess the effect of a traditional prosthesis on peri-implant soft tissue (Fig. 6), i.e. a prosthesis thatdoes not emerge from the mucosa like those onburied implants, but is supported by the gum likeany prosthetic bridge element on natural abut-ments, the kind usually employed with this typeof implant.

The most common criticism leveled against thesekinds of prostheses is that they do not permitproper oral hygiene, with the ensuing risk of per-implantitis. This work also aims to provide infor-mation about the epithelial attachment and itsdifferent functional interpretations, clarifying itsrole in the etiopathogenesis of periodontal dis-eases as a locus minoris resistentiae for hypothet-ical microbial invasion from the outside. We hy-pothesize that there is a sectoral frequency forcertain severe periodontal lesions, limited to oneor a few teeth in direct contact with periodontalareas that are instead healthy or affected to amuch lesser extent (39). There is no logical expla-nation for microbial virulence limited to the gumand periodontal tissues of a single tooth (or groupof teeth), while the same bacterial strain, at thesame concentration, is clearly harmless a few mil-

2 3

Fig. 2 The blade afterthe surgery. Note theperfect position of theblade’s upper surface,over 2 mm below thecortical bone.

Fig. 3 The biopsyspecimen at the necklevel of the Tramontescrews.

Fig. 4 Sectioncollected around apatient’s tooth affectedby periodontitis.

Fig. 5 Explorativevisualization of the newlyformed bone over theblade’s top surface andaround the neck of thetwo abutments 6 monthsafter surgery (1971).

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4 5

Fig. 6 Prosthesisplaced at casecompletion (1971).

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limeters from the lesions. This specific researchshows that there is no peri-implant pathologyaround the titanium implant abutments, whilethe periodontal disease of the soft tissues sur-rounding the natural abutment is clinically de-tectable and histologically confirmed.

Materials and MethodsThe specimens (Figs. 3, 7) were fixed in 5% for-malin, paraffin processed, cut into 4-mm-thickserial sections stained with hematoxylin-eosin(Fig. 8). Each biopsy specimen underwent twoidentical analyses in order to assess:❚ how the mucous epithelium in contact with the

emerging portion of the implant recessed andwas replaced by corium, and to what extent;

❚ the extent and differences in morphological be-havior that could be found at the epithelial at-tachment area of the natural tooth and the threeTramonte screws.

In order to progressively assess the histologicalpattern of the epithelium and submucous coriumat the epithelial attachment, the specimens weredivided into two groups, according to the twotypical cutting sections: orthogonal and parallelto the axis of the emerging screws and naturaltooth. Serial sections, orthogonal and parallel tothe mentioned axis, were then harvested, and thearea of the epithelial attachment was expected tobe found around it.The images should thus have shown the completepattern of the histological morphology for boththe external and internal mucous tissue in contactwith the neck of the screws and the natural tooth.In all, 2400 sections were examined.

Results All the serial sections of the mucosa attached tothe neck of the implants were histologically anal-ogous. The external mucosa was always protect-ed by an adherent keratin layer, below which itwas possible to detect the complete sequence ofepithelial layers up to the germinal cells of thebasal layer, spread along the digitations in the un-derlying corium. The metal-facing tissue was al-ways devoid of the keratin layer, with progressiveloss of the cellular layers up to a single layer ofbasal cells. Below it there was a perfectly normalcorium. A superficial section performed orthogo-nally to the implant axis, like the ones shown inFigures 9 and 10, clearly shows that the externalmucosa, indicated as letter “a”, is protected by adetectable keratin layer, while the internal layer(letter “b”) lacks keratin protection. A slightlydeeper section (Fig. 11) shows a thinner kerati-

Comparative histology of the neck area of a natural tooth IVand three Tramonte screws

7

Fig. 7 The arrows show how, with theprogression of the sections, thearchitecture of the external mucosa (a)will be examined histologically andcompared to that of the internal mucosa(b).

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Fig. 8 Overview of some of the 2400 histological specimens.

9

a ab b

ba

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Fig. 10 Original diagram illustrating the macroscopicmorphology of the specimen in Figure 3 (left) and showing theprogression of the orthogonal sections (right).

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nous layer and all the epithelial layers on the (a)side, while on the (b) side, the mucosa in contactwith the implant, the keratin layer is absent, as isthe underlying epithelial layer. The different mor-phology of the corium infiltrations, well-definedand abundant at the base of the external mucosa(a) and almost absent at the base of the internalmucosa (b), can also be observed. Figure 12 is another diagram representing theprogression towards the junction area of the sec-tions. A detail of Figure 11 at a higher magnifica-tion (Fig. 13) clearly illustrates the different ap-pearance of the internal and external mucosa.The diagram (Fig. 14) shows the position of thelast sections at the junctional area. Figure 15 alsoshows the difference between the external mu-cosa (a), with a keratin layer and all the epitheliallayers up to the numerous digitations of the deep-est layer, and the residue of the internal mucosa(b) in a regressive state, especially in the area in-dicated by the arrow. In Figure 16 the mucosa is reduced to a thin lay-er of germinal basal cells corresponding to thearea indicated by the arrow in the previous figure. An even deeper section (Fig. 17) shows in the ex-ternal mucosa composed of all layers in (a), whilein (b) the internal mucosa has disappeared, re-placed by the submucous corium. In Figure 18, a higher magnification of the previ-

11

a ab b

ba

12

13

a ab b

ba

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ous figure, (a) clearly shows the complete se-quence of epithelial layers and the well-defineddigitations in the underlying corium. Figure 19 illustrates a very different pattern: Themucosa pertaining to the biopsy specimen col-lected in the area surrounding the tooth affectedby periodontitis is inflamed and hypertrophic.The arrows indicate the marked progression ofthe papillae in the underlying inflamed corium.

DiscussionThe substantial number of examined sections andthe repetitive pattern of the histological speci-mens permit exhaustive analysis of the neck area.Moreover, the specimens collected around a nat-ural tooth affected by periodontosis in the same

oral cavity represent a very important element ofcomparison. The cell morphology of the periodontium adja-cent to the neck area of the natural tooth (a low-er right premolar with periodontal disease) showsclear signs of inflammation, recession and migra-tion of the epithelial attachment. Both in the seri-al sections performed along the parallel axis,which shows the pocket profile along the root ce-ment (Fig. 20), and in the orthogonal ones (Fig.21), one can clearly observe all the signs ofchronic inflammation of the epithelium and cori-um, with the typical increased infiltrations of thebasal membrane towards the deepest layers andclassic parvicellular infiltration of the tissues.In a few areas the increased digitation of the ep-ithelial basal layer almost reaches the oppositeside, possibly leading to the loss of the overlyingtissue due to necrosis (Figs. 22, 23). The histological pattern of the serial sections per-formed in the tissues surrounding the emergenceof the three Tramonte screws is quite differentand constantly normal in appearance. The sub-stantial morphological difference between the ex-ternal buccal and lingual epithelium and the in-


17

18

19 20

21

Fig. 21 Orthogonal section around the tooth affected withperiodontitis. Clear signs of phlogosis.

Fig. 20 Serial sectionperformed along the main axisof the root. Evidence ofabnormal epithelial digitations,parvicellular invasion andhemorrhagic suffusion due tothe inflammatory process(hematoxylin-eosin 180x).

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ternal epithelium facing the metal can clearly beobserved, and it is very well defined. The exter-nal epithelium always has the keratinous protec-tive layer and always shows papillary digitationsin the corium, reactive to the physiological stim-uli due to mastication. Even at a depth of 1–2mm, the internal epithelium loses the keratinouslayer and, moving toward the deepest serial sec-tions, it shows the progressive and regular reduc-tion of the cellular layer up to the corium. Whatis absolutely remarkable is the constant absenceof digitations, a clear sign of higher reactive cellturnover to irritative stimuli. This allows us tostate that the tissue arrangement around the abut-ments of the Tramonte screws, used as supportfor a traditional prosthesis, represents an ab-solutely normal pattern and, on an inductive lev-el, allows us to predict that the current state ofthe seal will be preserved for a long time.

This study made it possible to verify histological-ly that the morphology of the peri-implant bio-logical seal of these implants is identical to that ofthe epithelial attachment of natural sound teeth,and the following considerations can be made.❚ The three hemisections of all examined speci-

mens, collected in serial sections parallel to thealloplastic posts, always show the normal pro-file of the internal epithelium with no signs ofinflammation or disarray of the cellular mor-phology. Regarding the study focusing on thebiological seal area, it can be stated that the be-havior of the cellular layers and the underlyingcorium is identical to that ascertained by meansof analogous studies on natural teeth (Figs.24–27). Despite the lack of submicroscopic evi-dence of a specific insertion of the pseudopodsof the basal layer cells on the metal surface, fur-ther research demonstrated hemidesmosomaladhesion to the titanium surface, which is ableto form a true seal that isolates the internal cellspaces and discontinues the spatial communi-cation between the latter and the oral cavity.The permanence and consolidation of such aseal testifies to the absolute biocompatibility ofthese implants, which do not show signs of tis-sue degeneration in the area of their emergingportion when loaded with a prosthesis elevatedabove the peri-implant tissues.

❚ The three other hemisections, sectioned ortho-gonally to the main axis of the alloplastic posts,show similar behavior, varying only in the mor-phological appearance corresponding to thedifferent examined areas (Figs. 9, 11, 13,15–17).

22 23

Figs. 22, 23 Clear signs of inflammation of the periodontaltissues of the compromised natural tooth.

24 25 26

Fig. 24 Cytomorphology of the periodontal tissue around the neck of the implant. The layers of the internal mucosa areprogressively thinner (a), becoming single-layer. A perfectly normal corium can be observed below it.

Note the absence of epithelial digitations. Healthy external mucosa (b) (hematoxylin-eosin 120x).Fig. 25 Detail at a higher magnification. Note the even reduction of the internal epithelium layers going from the surface to the epithelial

attachment area (hematoxylin-eosin 240x). Fig. 26 The previous figure at a higher magnification (400x).Fig. 27 Detail of the epithelial attachment (400x). The sole presence of the basal cells is evident.

27

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Thirteen-year follow-upThe patient was reexamined 13 years after thefirst implant surgery (1980) for a checkup and toassess the implants’ osseointegration 10 years af-ter the bioptic specimens were taken. Figures 28and 29 respectively show the photograph and theorthopantomography taken at the time. Notably,13 years after the procedure tissue recession ismore severe on the natural teeth than around thescrews and the blade. The oral hygiene of the 81-year-old patient had deteriorated by this time, butthe peri-implant mucosa nevertheless appears tobe in good health, whereas around the naturalteeth (second lower incisor) the tissue is edema-tous and has reddened margins, the classic sign ofinflammation. The root has plaque deposits,which are absent on the implant abutments.Furthermore, gingival recession can be noted on-ly around the implants whose emergence ismarkedly buccalized, and it is thus a conse-quence of this particular condition. With the ad-vent of abutment translation, achieved by bend-ing the emerging necks and through better repo-sitioning of the abutments with respect to thecrest, this problem—which, as we can see, didnot affect the success of the implant—was solved. The OPG shown in Figure 29 reveals that, in themeantime, the upper left molar was lost and thesecond left premolar was replaced with an im-plant. The prosthesis was naturally shortened andadjusted in relation to the new oral conditions(Fig. 30). The intraoral radiographies (Figs.31–33) make it possible to verify the perfect os-seointegration of the four screws, surrounded bya layer of apposed compact bone. In particular,Figure 33 shows that the use of a long-neck im-plant permits more adequate positioning of thecoronal spiral and the abutment, in addition tobetter observance of the biological width, whileavoiding the small bone-resorption cones that canbe noted around the other three screws. In anyevent, it is important to consider the patient’s age,sex and the limited number of implants in rela-tion to bone quality, which gradually deterioratedfrom the time of the first implant rehabilitation.This also allows us to reassert that during the sur-gical planning phase it is essential to consider notonly the patient’s current condition, but also nor-mal and predictable future conditions, given theimplant’s proven ability to stay in place fordecades. The clinical appearance of the mucosae where theimplant abutments emerged was also excellent(Fig. 34). With the patient’s consent, surgical in-spection of the upper right canine was performed

by incision and flap detachment to expose theexternal surface of the including compact bone(Fig. 35). This image from many years ago revealsseveral interesting details: the buccal depressionfilled with blood visible in the apical area be-tween the two implants—barely noticeable in theX-ray and not treatable with the modern recon-structive techniques of the time—greatly influ-enced the implant insertions. The implant’s coro-nal thread is dehiscent due to severe horizontalresorption, but the surrounding bone is neverthe-less compact and completely normal. Lastly, ex-cessive deepening of the abutment in the mucosa,bringing it closer to the crestal bone, led to re-sorption reactions that were absent around theimplant of the upper left second premolar, whichwas inserted more correctly. This should per-suade all those applying this system to followmodern protocols and use short- and long-neckimplants skillfully.In any event, a periodontal probe forced into the


28

30

29

Fig. 30 The image shows the changes made to the prosthesisfollowing extraction of the left first molar and second premolar: reliningof the second upper premolar for insertion of the implant abutment,filing of the molar and filling of the residual cavity. It is interesting to notethat with using a smaller implant emergence makes it easier to find thebest implant site.

31 32 33

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junctional area was unable to penetrate it (Fig.36), also demonstrating the diagnostic limitationsof intraoral radiographic images.

ConclusionsThis study, performed on a 72-year-old patient(1971) with three Tramonte screws loaded fouryears earlier, remains one of the most comprehen-sive histological and anatomopathological exami-nations (with optical microscopy) ever performedon the junctional area of endosseous emergingimmediate-load implants. This research made itpossible to ascertain:❚ perfect healing of the bone tissue with no bone

loss around the neck of the three immediate-lo-ad Tramonte implants after four (1967–71) andthirteen (1967–80) years of service (40, 45);

❚ the constant absence of clinical signs of inflam-

mation of the tissues adjacent to the emergingarea of the implants;

❚ the morphological behavior of the tissues adja-cent to the Tramonte implant emergences,identical to the histological behavior of the pe-riodontium in contact with the neck area of na-tural teeth, at the resolution limit of optical mi-croscopes;

❚ the degenerative patterns, in the same patient,of a natural tooth with clinical and histologicalsigns of periodontal inflammation and chronicrecession of the epithelial attachment, withoutdamaging the excellent clinical and histologicalstatus of the implants;

❚ the absolute tolerability of a traditional pro-sthesis, which did not cause any kind of pro-blem with the implants after 13 years of servi-ce in a mouth where conditions had deteriora-ted, due both to the normal loss of tissue tro-phism caused by aging and the progressive de-cline of oral hygiene often observed among theelderly (46, 47).

Furthermore, we believe that it is safe to state thatthe theoretical assumptions underlying the designof this implant (which must be acknowledged asthe first implant specifically designed for imme-diate loading, the first with a biological widtharea at a time when this definition did not evenexist and, lastly, the first to use titanium in im-plant dentistry) proved to be valid based on out-come as well as additional studies and research(49). In a recent experimental clinical trial, overa period of about four years (1998–2001) a totalof 181 implants were inserted (158 Tramontescrews and 23 implants with narrow threadingand fitted with a prosthetic connection): 103 im-plants were inserted in the upper arch (57.2%),and 78 in the lower arch (42.8%) (49). At the endof the follow-up period, 96% of the placed im-plants proved to be successful. Failures were as-cribable to splinting problems and implant soli-darization, i.e. to fracture of the temporary pros-thesis. Considering the two different types of im-plant, the wide-thread implant showed a successrate of 97.5%, whereas the success rate for thenarrow-thread type was 87%.This concluded the study, which spanned nearly40 years, going from Tramonte’s implant place-ment (1967) a few years after the introduction oftitanium in implant dentistry (1963–64) to thefirst extensive histological research on the peri-implant biological seal in humans (1972), and onto a recent university study (2002) endorsing thedesign characteristics of the endosseous portionof this implant as the most suitable for immediate

34

36

35

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loading. This also concurs with the theoreticalstudies conducted by Lemons on the biomechan-ics of implant morphology and by James on themost appropriate implant emergence size in orderto avoid peri-implant resorption.

References

1. TRAMONTE S.M. Un nuovo metodo di impianto endos-seo. Proceedings of the 5th National SIOCMS CongressSIOCMS; Naples, Italy. 1962.2. TRAMONTE S.M. A proposito di una modificazione sugliimpianti alloplastici. Rass Trim Odont 1963;44(2)129:36.3. TRAMONTE S.M. Intrabone implants with drive screws. JOral Impl Traspl Surg 1965;4:126.4. TRAMONTE S.M. Implante endoseo racional. Metodopersonal. Actos de la IV reunion de la SEI; Madrid. 1965.5. TRAMONTE S.M. A further report on intra-osseus im-plants with improved drive screws. The Journal of Implantand Transplant Surgery 1965;11:35-37.6. TRAMONTE S.M. Implantologie endo-osseuse: préjugé-es et craintes. L’Information Dentaire 1966;8:148.7. TRAMONTE S.M. Su alcuni casi particolarmente interes-santi di impianto endosseo con vite autofilettante. Ann Stom1966;15(4):320.8. TRAMONTE S.M. L’impianto a vite autofilettante. Riv ItImplant 1966;1:95.9. Tramonte S.M. Intraosseous self-threading implantations.Personal method. Dent Cadmos 1971 Feb;39(2):192-208. 10. TRAMONTE S.M. L’impianto a vite autofilettante nella so-stituzione di un solo dente mancante. Riv Eur Implant1978;4:15-21.11. TRAMONTE S.M. L’impianto endosseo a vite autofilettan-te. Riv Eur Implant 1979;11:25-32.12. TRAMONTE S.M. Su di un caso particolarmente interes-sante. Riv Eur Implant 1981;2:12-25.13. TRAMONTE S.M. Vite endossea autofilettante. AttualitàDentale 1989;7:44-9.14. TRAMONTE S.M. L’impianto endosseo a vite a carico im-mediato. Proceedings of the 27th GISI International Meetingon Dental Implants and Transplants; Bologna, Italy. 1997. p.71.15. IGLESIAS J.G. La epoca heroica de la implantologia enEspana. Los pioneros. Madrid: Edizioni SEI; 1996. p. 136.16. TRAMONTE S.M. Implante endoseo racional. Metodopersonal. Atti della IV Reunion de la SEI; Madrid. 1965.17. CAMERA A., PASQUALINI U. Impianti endoossei: isto-logia comparata della “zona del colletto” in un dente natura-le, due monconi di Linkow e tre viti di Tramonte. Associazio-ne Italiana Impianti Alloplastici 1972;3.18. LEMONS J.E. Considerazioni sui fattori biomeccanici esui biomateriali degli impianti a forma di radice. In: McNeiliC. L’occlusione. Basi scientifiche e pratica clinica”. Milano:Scienza e tecnica dentistica; 1997. p. 195-202.

19. JAMES R.A. Basic principles of endosteal dental implantdesign. In: Hardin JF editor. Clark’s Clinical Dentistry. Phila-delphia: JB Lippincott; 1981.20. LINKOW L., CHERCHÈVE R. Theories and techniquesof oral implantology. St. Louis (USA): CV Mosby Co; 1970.21. CAMERA A., PASQUALINI U. Comportamento dell’epi-telio umano intorno ai perni uscenti degli impianti endossei.Associazione Italiana Impianti Alloplastici 1972.22. COCHARD D.L., HERMANN J.S., SCHENK R.K., HIG-GINBOTTOM F.L., BUSER D. Biologic width around tita-nium implants. A histometric analysis of the implanto-gingi-val junction around unloaded and loaded nonsubmerged im-plants in the canine mandible. J Periodontol 1997Feb;68(2):186-98.23. GOULD T., WESTBURY L., BURNETTE D.M. Ultrastruc-tural study of the attachment of human gingiva to titaniumin vivo. J Prosthet Dent 1984 Sep;52(3):418-20.24. Hashimoto M, Akagawa Y, Nikai H, Tsuru H. Ultrastruc-ture of the peri-implant junctional epithelium on single-cry-stal sapphire endosseous dental implant loaded with functio-nal stress. J Oral Rehabil 1989 May;16(3):261-70.25. JAMES R.A., SCHULTZ R.L. Hemidesmosomes and theadhesion of junction epithelial cells to metal implants. A pre-liminary report. J Oral Implantol 1974;4:264.26. JAMES R.A., KELLN E.E. A histopathological report onthe nature of the epithelium and underlying connective tis-sue which surrounds oral implant. J Biomed Mat Res1974;8(4 pt 2):373-383.27. LISTGARTEN M.A., LAI C.H. Ultrastructure of the intactinterface between an endosseous epoxy resin dental implantand the host tissues. J Biol Buccale 1975 Mar;3(1):13-28.28. LISTGARTEN M.O. Indagini al microscopio elettronicosulla giunzione dento-gengivale nell’uomo. Classici della let-teratura odontoiatrica a cura di Giorgio Vogel. Milano: Edi-zioni GEC;1976.29. MC KINNEY R.V. Jr, STEFLIK D.E., KOTH D.L. Eviden-ce for a Junctional epithelial attachment to ceramic dental im-plants. A trasmission electron microscopy study. J Periodon-tol 1985 Oct;56(10):579-91.30. MC KINNEY R.V. Jr, STEFLIK D.E., KOTH D.L. The epi-thelium dental implant interface. J Oral Implantol1988;13(4):622-41.31. Ruggeri A, Castellani PP, Franchi M, Ciusa R. Optic andelectronic microscope study on the implant-tissue interface oftitanium dental implants. Minerva Stomatol 1985 Sep-Oct;34(5):835-45.32. RUGGERI A., FRANCHI M., MARINI N., TRISI P., PIAT-TELLI A. Supracrestal circular collagen fiber network aroundosseointegrated nonsubmerged titanium implants. Clin OralImplants Res 1992 Dec;3(4):169-75.33. RUGGERI A., FRANCHI M., TRISI P., PIATTELLI A. Hi-stologic and ultrastructural findings of gingival circular liga-ment surrounding osseointegrated nonsubmerged loaded tita-nium implants. Int J Oral Maxillofac Implants 1994;9:636-43.34. Piattelli A, Ruggeri A, Franchi M, Romasco N, Trisi P. An


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histologic and histomorphometric study of bone reactions tounloaded and loaded non-submerged single implants inmonkeys: a pilot study. J Oral Implantol 1993;19(4):314-20.35. SANTORO J.P. È possibile l’attacco epiteliale al monconedell’impianto. Odontostomatol Implantoprotesi 1975;4.36. SARNACHIARO O., BONAL O., GRATO BUR E., VAA-MONDE A. Histologische untersuchung des selbsschneiden-de Garbaccio Titan. Schraubeimplantats (Bicortical Schrau-be) im Tieversuch. Orale Implantologie 1986;12:33-8.37. SWOPE E.M., JAMES R.A. A longitudinal study on he-midesmosome formation at the dental implant-tissue over-flow. J Oral Implant 1981;9:412-22.38. VERNOLE B, BARBOLINI A. Studio istopatologico dellezone del colletto peri-impiantare. Odontostom e Implanto-protesi 1976;2. 39. PASQUALINI U. L’eziopatogenesi occlusale delle gengi-viti ipertrofiche marginali. In: Pasqualini U. Le patologie oc-clusali. Eziopatogenesi e terapia. Milano: Masson; 1993. p.1617.40. BIANCHI A., GALLINI G., FASSINA R., SANFILIPPO F.Analisi al SEM dell’interfaccia osso-impianto di una vite sot-toposta a carico funzionale immediato. II Dentista Moderno1994;9:1499-1503.41. BIANCHI A., SANFILIPPO F., ZAFFE D. Implantologia eimplantoprotesi. Basi biologiche. Biomeccanica. Applicazionicliniche. Torino: UTET; 1999. p.159-257.42. DONATH K., NYBORG J. Esame istologico (post mor-tem) di una mandibola con sei viti bicorticali. Odontostom eImplantoprotesi 1991;8.

43. PASQUALINI U., MANENTI P., PASQUALINI M.E. Inda-gine istologica su ago emergente fratturato. ImplantologiaOrale 1999 Apr;2(2):42-4.44. PASSI P., MIOTTI A., CARLI P.O., DE MARCHI M. Tra-monte screw for replacement of single teeth. G Stomatol Or-tognatodonzia 1989 Apr-Jun;8(2):83-8.45. ROSSI F., PASQUALINI M.E., MANGINI F., MANENTI P.Carico immediato di impianti monofasici in mascellare supe-riore. Dent Cadmos 2005;4:65-9.46. TRAMONTE S.U. La massima espressione del carico im-mediato: interventi d’implantologia avanzata in mandibola emascellare atrofici. Proceedings of the 4th International AISICongress AISI; Verona, Italy. 2002. p. 455-70.47. ZEROSI C. Comunicazione sull’istologia dei tessuti intor-no a monconi implantari. Proceedings of the 10th Internatio-nal Meeting on Dental Implants and Transplants; Bologna,Italy. 1980. 48. LORENZON G., BIGNARDI C., ZANETTI E.M., PETRU-SIO R. Analisi biomeccanica dei sistemi implantari. DentCadmos 2003;71(10):63-86.49. BERTELÉ P., PASQUALINI M.E., BILUCAGLIA L., MI-RANDOLA A. Implantologia: dall’ipotesi al carico immedia-to. European Journal of Implant Prosthodontics 2006 May-Aug;2(2):65-87.

The chapter, “Comparative Histology of the Neck Area of a NaturalTooth and Three Tramonte Screws”, is from the supplement to Doctor Os 2005 Nov-Dec;16(9):1–10.

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CHAPTER IXin collaboration with Pier Maria Mondani

In the first half of 1970s, screws and blades al-most completely overshadowed the reputationof Scialom’s tantalum tripod implant technique,

which was very effective and virtually atraumatic(1-3). In Italy only a few were still using Scialo-m’s needles, and Pieluigi Mondani was one ofthem.He employed a solder he had invented, whichblocked the outer extremities of the needles in asimpler, faster and more secure way than the oldtechnique with self-curing resin blocks. In placeof tantalum he used titanium needles that differedin thickness but were equally suitable for solder-ing (Fig. 1).In Italy more than 350 implantologists now usehis intraoral solder. Presented in 1978 at the Con-gress of Implantology and Maxillofacial Surgeryheld in Ortisei (Bolzano, Italy), his “machine”sparked enormous interest.Initially, however, no one except the inventordared to use “an electrical device” that had toreach a melting point of 1678° C in order to sol-

der - directly in the patient’s mouth - the ends ofmetallic artifacts placed in the bone (4). Later Mondani’s technique was employed at theSpecialization School of Dentistry of the Univer-sity of Modena, where it was tested and certifiedas safe, as it does not harm the tissues with whichit comes into contact1 (5, 6).The “machine” could also weld iron, steel and anymetal alloy that could oppose direct current. Itwas not effective on gold, copper or any othergood electrical conductor, because it worked ex-clusively by exploiting the highest temperatureproduced by the resistance of bad conductors toelectric current. Now we will spend a few words on how this waspossible without burning the tissues. The “biocompatibility” of the soldering, whichoccurs at 1678° C on the protruding and closelyset portion of the needles placed in living tissue,is due to the fact that the electric current needs aworking time of just 2-3 milliseconds. This mi-cro-time, combined with the calculated pressureof the electrodes on the structures to be soldered,prevents the diffusion of the tremendous heatgradient beyond the welding point. Apart frombeing a bad conductor, titanium also has lowthermal conductivity very similar to that ofenamel. While industrial welders melt titanium only inthe presence of argon and in the absence of at-mospheric oxygen, Mondani’s small solder weldsthe titanium needles (and other materials of re-duced thickness) in the presence of air or evenunderwater (Figs. 2-7). To summarize, spot welding involves threestages.

THE MONDANI INTRAORAL SOLDER

1

Fig. 1 Left: a tantalum needle inserted in its mandrel. Right:titanium needles differing in thickness (from 1.1 to 1.5 mm) firstused by Pierluigi Mondani. 1 Except wearers of cardiac pacemakers.

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1) Current passes through the welding circuit at avoltage proportional to required energy, accord-ing to the formula E=V2xC/2, where E is energy,V is the voltage of the loaded capacitor, and C isthe electrical value of the capacitor. The currentflows through the needles, heating and weldingthem together.

2) The welding is aided and facilitated by the con-stant pressure exerted by the pliers on the sur-faces to be welded.

3) The welding time (2-3 milliseconds) and thetiming distribution of the two foregoing param-eters create welding cycles that are repeated ateach spot.

Mondani’s intraoral solder also makes it possible to:

2

8

9

10

3

6 7

4

5

Fig. 2 The intraoral solder.Fig. 3 Detail of the soldering pliers.Fig. 4 Schematic drawing of the soldering principle. Left: 3diverging bicorticalized needles. Right: the 3 needles to besoldered after bending.Fig. 5 Left: soldering. Right: the abutment that was created isfitted for a crown.Fig. 6 Soldering of 3 needles to create an abutment.Fig. 7 Soldering in water.

Fig. 8 Splinted bar over an arch treated only with needles.Fig. 9 X-ray of the previous case, treated with needles and asplinting bar.Fig. 10 The definitive prosthesis.

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1) connect and splint the various tripodial (orquadripodial) abutments or the single needlesof a whole arch using bars, forming a singleblock that is very resistant to the occlusalstress of temporary or definitive prostheses,which can be placed on it immediately (Figs.8-10) (7-9);

2) splint other types of implants for both perma-nent and temporary stabilization during inte-grating osteogenesis (Figs. 11-15) (10, 11);

3) remedy possible stress fractures of the needlesor any other type of titanium implant (screws,blades, etc.) by welding a new abutment di-rectly in the mouth (Figs. 16-20) (12, 13);

4) increase the stability of different types of im-

The Mondani intraoral solder IX

11 12

13

14 15

Fig. 11 Two mini-implants (MUM).Fig. 12 Splinting with a titanium bar.Fig. 13 Cast with the definitive crown; the arrow indicates thetechnical preparation, permitting correct cementation, and goodoral hygiene.Fig. 14 The cemented single crown.Fig. 15 Radiographic checkup.

17

18

19

20

Fig. 16 Stress fracture of a blade neck due to mobility andloss of the distal natural abutment.Fig. 17 Localization of the base of the fractured neck.Figs. 18, 19 Mondani’s intraoral solder used to repair theblade that underwent stress fracture.Fig. 20 X-ray taken after welding a new prosthetic abutment;the arrow indicates that the blade fracture was caused bymobility of the distal natural abutment.

plants by soldering one or two balancing nee-dles, thus distributing the load to the corticalbone (Figs. 21, 22) (14-18).

In later chapters we will describe the other uses ofthe solder. We have intentionally used the term “intraoral sol-dering” despite the fact that, from a technical stand-

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point, it is not a fusion or actual soldering, butrather a more stable process of molecular syncrys-tallization (Figs. 23, 24).Regarding the technical knowledge required to per-form intraoral soldering correctly, the physical dif-ference between fusion, soldering and syncrystal-lization has no practical consequences.We believe that this brief overview of Mondani’s in-traoral solder can suffice to present it as a remark-able step forward in the evolution of implantology(Figs. 25-30).We do not intend to provide technical details thatcan be found in physics books, as this does not fallwithin bounds of the medical-surgical field. More-over, they are detailed in the brochures of the com-panies that sell these solders. Those who limit their practice to submerged implants(two-step) have seriously underrated the value of thisbrilliant device, which is still an essential tool for pro-fessionals who exploit all the implant techniques thatcan rehabilitate most cases of edentulous ridges. We will end this chapter with the hope that, in thefuture, the technique described here will gain theconsideration it deserves among implantologistswho are not acquainted with it yet (Figs. 31-39)(19-23).

21 22

Fig. 21 Bicorticalized single-step screw, and soldered balancingneedle.Fig. 22 Definitive crown, and appearance of the mucosa.

23 24

25

26

28 29

30

27

Fig. 23 Molecular syncrystallization of two titanium implantfixtures.Fig. 24 Magnified detail of the interweaving of the “metal fibers” afterwelding with the intraoral solder.

Fig. 25 Loss of the upper central incisor in a young patient;note the agenesias and diastemas (1984).

Fig. 26 The X-ray of the edentulous area shows the presenceof residual amalgam due to the retrograde obturation of the

natural teeth replanted after trauma; complete rhizolysisoccurred 4 months after replantation.

Fig. 27 Detachment of the flap shows the very thin bone.Fig. 28 Placement of 3 divergent bicorticalized titanium

needles (diameter 1.2 mm). Fig. 29 Postoperative X-ray.Note the divergence of the 3 needles, their welding into a singleabutment, and the presence of non-resorbable hydroxyapatite

granules in the area where the amalgam was removed, to avoidcollapse of the repositioning flap.

Fig. 30 Suture and immediate temporary crown.

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References

1. SCIALOM J. Needle implants. L’Information Dentarie1963;5:253-266.2. SCIALOM J. Implants aiguilles (pin implants). J Oral Im-plant Transplant Surg 1965;11:18-23.3. SCIALOM J. Answers to questions relating to needle im-plantation. Rev Odontoimplantol 1972 Oct-Dec;6(46):7-14.

4. MONDANI P.L., MONDANI P.M. The Pierluigi Mondaniintraoral electric solder. Principles of the development andexplanation of the solder using syncrystallization. Odonto-stomatol Implantoprotesi 1982 Jul-Aug;(4):28-32.5. HRUSKA A.R. Intraoral welding of pure titanium. Quin-tessence Int 1987 Oct;18(10):683-688.6. HRUSKA A.R., ZAPPE W. Intraoral welding of pure tita-nium. Quintessenz 1988 Jan;39(1):35-48.7. LORENZON G., BIGLIARDI C., ZANETTI E.M., PERTU-GIO R. Analisi biomeccanica dei sistemi implantari. DentCadmos 2003;10:63-86.8. PASQUALINI M.E., MANGINI F., COLOMBO D., ROSSIF. Stabilizzazione di impianti emergenti a carico immediato.Saldatrice endoorale. Dent Cadmos 2001;9:67.9. MONDANI P.L., CANTONI E., MONDANI P.M. New me-

The Mondani intraoral solder IX

31 32

34 35

39

33

36

37 38

Fig. 31 At 3 months, appearance of the mucosa surrounding the abutment after the temporary crown was removed. The immediatetemporary one was useful for aesthetic remodeling of the soft tissue, restoring the architecture of the papillae. Fig. 32 Definitivegold-porcelain crown (1985). Fig. 33 X-ray (1985). Fig. 34 Follow-up at 5 years (1990). Fig. 35 Radiographic checkup

after 5 years (1990). Fig. 36 Gingival stippling of the peri-coronal mucosa after 12 years (1997).Fig. 37 Replacement of the crown2 for purely aesthetic reasons, requested by the patient after 12 years of service because her

teeth, with diastemas and maloccluded, were slightly longer than the single-tooth implant, which was still perfectly osseointegrated.Fig. 38 The new crown; clinical appearance after 15 years (2000). Fig. 39 Radiographic checkup (2000).

2 After 12 years the patient returned and ask to have the porcelain ofthe single-tooth implant lengthened, because the other natural teeth,with diastemas and in malocclusion due to agenesis of the two lowerlateral incisors, had extruded in the meantime (see photographicdetail). The crown was replaced with a different one that was bettersuited to the new conditions, after occlusal rebalancing.

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thod for the reduction of mandibular fractures. Riv Odonto-stomatol Implantoprotesi 1983 Jul-Aug;(5):45-7.10. ROSSI F., PASQUALINI M.E., MANGINI F., MANENTI P.Carico immediato di impianti monofasici nel mascellare su-periore. Dent Cadmos 2005;73(4):65-69.11. BERTELÉ G., PASQUALINI M.E., BILUCAGLIA L., MI-RANDOLA A. Implantologia: dall’ipotesi al carico immedia-to. European Journal of Implant Prosthodontics 2006 May-August;2(2):65-87.12. PASQUALINI M.E. Le fratture da fatica dei metalli da im-pianto. Il Dentista Moderno 1993;XI(2):31.13. LORENZON G., BIGNARDI C., FANALI S. Insuccessiimplantari da frattura. Il ruolo della fatica dei materiali. Eu-ropean Journal of Implant Prosthodontics 2007 Spring;3(1):7-17.14. LORENZON G. Sincristallizzazione a flusso di Argon.Dental Tribune 2007 febbraio;3:7-14.15. APOLLONI M. Atlante pratico di implantologia dentale.Milano: Ed. Ermes;1989:70-98.16. MONDANI P.L., MONDANI P.M. Impianti pilastro salda-ti con protesi totale rimuovibile a telescopio. Riv. EuropeaImpl. 1983;2:27.17. NARDONE M., VANNINI F. Implantologia ad aghi neisettori posteriori mandibolari atrofici: passato o attualità?Chir Orale 2007;2:13-17.18. NARDONE M., VANNINI F. Implantologia emergente

elettrosaldata: metodica, materiali e clinica. Doctor Os 2008Giu;19(6):641-48.19. DEGIDI M., GEHRKE P., SPANEL A., PIATTELLI A. Syn-crystallization: a technique for temporization of immediatelyloaded implants with metal-reinforced acrylic resin restora-tions. Clin Implant Dent Relat Res 2006;8(3):123-34.20. HRUSKA A.R., BORELLI P. Intra-oral welding of implantsfor an immediate load with overdentures. J Oral Implantol1993;19(1):34-8.21. HRUSKA A.R. Welding implants in the mouth. J Oral Im-plantol.1989;15(3):198-203.22. BUCCI SABATTINI V. Tecniche ricostruttive e rigenerati-ve dei mascellari atrofici. I biomateriali: scelta, indicazioni emetodi di uso. Torino: TU.E.OR.; 2007. p. 284-8.23. DAL CARLO L. Tecnica di protesi fissa su barra saldatanelle contenzioni definitive. Doctor Os 2004 Giu;15(6):637-45.24. DAL CARLO L. Las numerosas aplicaciones de la salado-ra intra-oral de Mondani. 17 anos de experiencia clinica. RevEsp Odontoestomatologica de Implantes 2006;14(1):23-24.

Figs. 25–39 taken from M.E. Pasqualini, F. Mangini, D. Colombo andF. Rossi, “Stabilizzazione di impianti emergenti a carico immediato.Saldatrice endorale.” Dent Cadmos 2001;9:67-75.

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CHAPTER V

F rom a chronological standpoint, this inven-tion pertains to the innovations in implantdentistry of the 1960s. It rose to fame du-

ring the following decade, when it was modifiedand improved, becoming the most widespread im-plant in the world for a certain period. We willthus review its history, evolution, and current un-justified decline.

Linkow’s blade implants

The blades that Linkow presented in 1968 markanother milestone in the evolution of implantol-ogy (1).Although Linkow was still unknown in Europe atthe time, he was certainly not an outsider. His firstwork on implants had been published 14 yearsearlier (1954), and was followed by 24 others be-fore the one in which he presented his blades. Inshort, these implants are not the result of improv-isation, but the product of lengthy research to findan alternative to traditional prostheses (2–26).The concept, as Linkow himself acknowledged,has several analogies with a more rudimental anddifferently placed implant used towards the end of1967 by Roberts (27), who employed anchors inlaminated and vented titanium with one or twoexternal abutments, inserted into linear surgicalgrooves. The Italian Pedroni (28) and the Ameri-can A. Norman Cranin (29) had almost simultane-ously presented their anchor blade implants,which were vaguely similar to Linkow’s blades(Figs. 1, 2).This does not detract from Linkow’s work in anyway, as he gave his titanium blades shapes and

versatility in terms of application that were morepractical and far broader in scope.The implant placement is performed in open sur-gery to visualize the bone, where a groove is madealong the ridge crest to insert the submerged por-

THE BLADE IMPLANT

Fig. 1 The various designs of the first-generation Linkowblade (1968–69).Fig. 2 Close-up of some of Linkow’s blade shapes.

1

2

Introduction

96


tion of the blades (Figs. 3–5). The grooves are pre-pared with fissure burs (700 XL or 700 XXL, ac-cording to the shaft length) mounted on a high-speed handpiece. The grooves should accommo-date the entire endosseous portion of the blades.Bone drilling requires the concomitant use of awater-jet cooling (Figs. 6–8).The blades have different shapes that can beadapted to the morphology of the area to be reha-bilitated, and they are vented to allow inclusion bythe new bone, which will fill the voids as it forms(Fig. 9). Manually placed at the groove opening, theblade is subsequently placed with the aid of an awlor a chisel, and gently tapped into position with ahammer made of surgical steel and/or Teflon. Theshoulders of the blade should be buried at least 2–3mm below the groove margin, so that it will be cov-ered completely by new bone during the healingperiod. For curved grooves, the blades must bebent appropriately before placement. One or twotall posts emerge above the sutured mucosa and theauthor recommends that they be loaded as soon aspossible, joining them with as many residual natu-

ral teeth as possible. Based on his experience, thisprocedure promoted their subsequent stability.Linkow immediately started a very intense cam-paign to teach this method, not only in order to cir-culate it, but also to promote the sales of his blades.He performed surgery on volunteer patients, oftenfilming the operations to show them to the numer-ous colleagues who watched the demonstrations.The commercial organization that took over thesales of the blades forced him to go on exhaustingworld tours, and newspapers and magazines adver-tised the advantages of his “invention.” Profession-al ethics aside, this propaganda can nevertheless becredited with circulating the method, and, indirect-ly, all other implant rehabilitation techniques.The author promptly co-wrote a two-volume workwith the Frenchman Cherchève: Theories and Tech-niques of Oral Implantology (30). On page 92 of thefirst volume he reproduced the diagram—whichhad already been published a decade earlier—inwhich Pasqualini proposed his sagittal grooveamong the techniques for making the implantgroove. Fully acknowledging him, Linkow also in-cluded a few two-step implants, as well as severalhistological and anatomopathological demonstra-tions of their inclusion by direct bone apposition,without the juxtaposition of fibrous tissue (31)(Figs. 10–11).He aimed to prove that, even within the emptyspaces of his blade-vent implants, the integratingnew bone would form seamlessly, obviating theneed to eliminate external stress, whose importancehe did not fully understand at the time. Indeed, his

Fig. 3 A 700 XXL calibrated bur and one of Pasqualini’s universal blades (used to illustrate the surgical endosteal insertion technique).Fig. 4 X-ray of a blade receiving site. Fig. 5 Surgical bur mounted on a high-speed handpiece during the execution

of a longitudinal groove. Fig. 6 Detail of the bur working under a water jet. Fig. 7 The blade is placed in the surgical groove and tapped using an awl and a hammer. Fig. 8 The radiograph shows the correct placement of the blade (the shoulder is buried

2 mm below the level of the alveolar crest).

Fig. 9 Another example of a correctly placed blade.

3 4 5

6 7 8

9

97

blades had large posts that, unlike Pasqualini’scylinders, seemed to have no negative effects on theosseointegration of the submerged portions (Fig.12).Figure 12 illustrates a case that was treated in 1970and remained successful for many years. In the fol-lowing chapters, we will examine why other casesfailed.

References

1. LINKOW L.I. The blade vent-a new dimension in endos-seous implantology. Dent Concepts 1968 Spring;11(2):3-122. LINKOW L.I. The unilateral implant. Dent Dig non DentDic 1954;60:302-6.

3. LINKOW L.I. Implantation unilateral. Oral Hyg 1957 Ju-ne-July;6:48.4. LINKOW L.I. An evaluation of the unilateral implant; a fi-ve year report. Dent Dig 1958;14:383-7.5. LINKOW L.I. Abutments for full mouth splinting. J Pro-sthet Dent 1961;11(5):920-4.6. LINKOW L.I. Full arch splint. J Prosthet Dent1961;11:1117.7. LINKOW L.I. Contact areas in natural dentitions and fixedprosthodontics. J Prosthet Dent 1962;12(1):132-7.8. LINKOW L.I. Mesially tipped mandibular molars. J Pro-sthet Dent 1962;12(3):554-8.9. LINKOW L.I. Reconstruction of anterior teeth with extre-me vertical and horizontal overlap. J Prosthet Dent1962;12(5):947-50.10. LINKOW L.I. Full arch oral reconstruction – semplified.New York: Springer Publishing Co; 1962.11. LINKOW L.I. Evaluation of the unilateral implant eightyears report. Dental Digest 1962;68:158-68.12. LINKOW L.I. Intra-osseous implant utilized as fixedbridge abutments. J Oral Implant Transplant Surg1964;10(2):17-23.13. LINKOW L.I. Importance of axial inclinations of teeth inattainment of parallelism. J Prosthet Dent 1965;15(3): 517-24.14. LINKOW L.I. Metal implants assessed. Dent Times1965;9(9):6-7.15. LINKOW L.I. Clinical evaluation of the various designedendo-osseous implant. J Oral Implant Transplant Surg1966;12:35-46.16. LINKOW L.I. The age of endosseous implants. DentConcepts 1966;18(3):4-10.

The blade implant V

Fig. 10 Linkow’s letter asking Pasqualini for permission to publish the latter’s histological study on dogs in Theories and Techniquesof Oral Implantology. Fig. 11 Close-up of Linkow’s citation of Pasqualini’s work.

Fig. 12 Example of a case treated in 1970 with a Linkowblade-vent; it remained in service for many years.

10

12

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17. LINKOW L.I. The radiographic role in endosseous im-plant interventions. Chronicle 1966 Jun;29(10):304-11.18. LINKOW L.I. Maxillary endosseous implants. Dent Con-cepts 1966 Summer;10(1):14-24.19. LINKOW L.I. The versatility of implant intervention.Dent Concepts 1966 Fall;10(2):5-17.20. LINKOW L.I. L’era degli impianti endoossei. Inform Sto-mat 1966;8:14-15.21. LINKOW L.I. The era of endosseous implants. J Dist Co-lumbia Dent Soc 1967 Jun;42(2):46-7.22. LINKOW L.I. Prefabricated endoosseous implants pro-stheses. Dent Concepts 1967;10:3.23. LINKOW L.I. Re-evaluation of mandibular unilateralsubperiosteal implants: a 12 year report. J Prosthet Dent 1967May;17(5):509-14

24. LINKOW L.I. Internally threaded endosseous implants.Dent Concepts 1967 Summer;10(4):16-20.25. LINKOW L.I. Atypical implantations for anatomicallycontraindicated situations. Dent Concepts 1967-1968Fall;11(5):11-7.26. LINKOW L.I. Pin implants. Prom Dent 1968;3:4-15.27. ROBERTS – Quoted by Linkow.28. PEDRONI – Quoted by Muratori.29. CRANIN – Quoted by Linkow and Muratori.30. LINKOW L.I., CHERCHÈVE R. Theories and techniquesof oral implantology. St. Louis (USA): CV Mosby Co; 1970.31. PASQUALINI U. Reperti isto-anatomo-patologici e de-duzioni clinico chirurgiche di 91 impianti alloplastici in 28animali da esperimento. Riv Ital Stomatol 1962;12:1180-281.

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CHAPTER VI

One of the drawbacks of the Linkow techniquewas the need for the constant refurbishment ofthe different blades, as the set came with no“spares” and thus whenever one of the blades wasused it had to be replaced (Fig. 1).Both Pasqualini and Muratori incorporated differ-ent shapes into a single blade, which could beadapted to the morphology of each implant site.Muratori’s universal blade implant (Fig. 2) andPasqualini’s polymorphic blade, both of whichwere presented in 1970, will be described in hereand in the following chapters, along with indica-tions for their optimal use. Other customizableblades were later designed by Binderman andShapiro (1972), Foscarini (1975), Linkow again(1981), Tramonte (1982), Pierazzini (1983), LoBello (1986) and, in Germany, Grafelmann.

Giordano Muratori’s universal blade

Muratori invented a universal type of blade implantthat could be modified before insertion to cater tothe morphology of the individual being treated(1–3). He wrote that several motivations inspiredhim to design it:1) the advantage of having a single blade that could

be adapted for each case, without havingto choose among a large number of standardshapes;

2) the execution of simpler prostheses, since thesame readymade caps for his screws could alsobe used with the universal blade;

3) optimal exploitation of available bone, since theuniversal blade can always be adapted to the ex-act inner bone structure of the edentulousridges;

4) economic benefits because each case can betreated with just a few blades, without needingto keep all of Linkow’s different blades on handat all times.

The shapes that can be obtained are virtually infi-nite. Each user can select the design that best fits hisor her approach: perforated or incised blades,blades with wide or narrow holes, blades that arevented to a greater or lesser degree, and so on.Before it is modified, the blade is a smooth titani-um plate, with one or two posts that can accommo-date the standard caps designed for hollow screws.The preparation technique, which is relatively sim-ple, is performed in several steps.1) Intraoral radiography of the site to rehabilitate

is performed with the long-cone parallelingtechnique, which produces accurate imagesthat reflect the longitudinal dimensions of theridge.

2) The film that is thus obtained is dried and placedon a diaphanoscope, and the blade shape bestsuited for the morphological conditions of thesite is penciled over it.

3) A clear adhesive sheet is then placed over thefilm and the underlying drawing is copied ontoit.

Introduction

MODIFICATIONS TO THELINKOW BLADE IMPLANT

Fig. 1 Linkow blades of different shapes (1969).Fig. 2 Muratori’s universal blade (1970).

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100


4) The clear adhesive sheet with the traced shape isdetached from the film and attached to the bladeplate (with one or two posts, as needed).

5) The blade and the attached sheet are then sentto the lab, where the contour design will be out-lined with a carbide bur and then finished ac-cording to the specialist’s indications.

The posts of the universal blades can be bent witha pair of pliers in both the buccolingual andmesiodistal directions. The surgical technique forinserting it is essentially the same as the one pro-posed by Linkow. The Muratori’s universal blades were truly custom-made. However, the neck of the posts, which couldbe bent easily, was too thin to exclude the risk ofstress fractures over time.Pasqualini observed the fracture of the post of auniversal blade after seven years of service, whichhe had to remove altogether with the surroundingbone tissue, replacing it with a new blade (Figs.3–9).Obviously, no implant is free from the risk of stressfractures, potentially caused by manufacturing de-fect1 or occlusal overload.

Ugo Pasqualini’s polymorphicblade implant

Pasqualini described his implant in great detail inhis notes.

10

1 One of the first studies on stress fractures in implant metals was presented at the International GISI (Italian Implant Study Group) Congress in Bologna in1992 and published by M.E. Pasqualini, Le fratture da fatica dei metalli da impianto in Il Dentista Moderno 1993; 2:31.

Fig. 3 X-ray of a case treated with Muratori’s universal blade (1972). The picture on the right was traced with a marker by Muratori himself toindicate the two holes and the new outline. Fig. 4 Radiographic detail of the blade implant and the final bridge. Fig. 5 Fracture of the

blade neck after 7 years of service (1979). Fig. 6 Macroscopic appearance of the osseointegrated blade.Fig. 7 Osteotomy performed for blade removal. Fig. 8 Blade with bone tissue of the well-osseointegrated implant.

Fig. 9 The histological examination confirms osseointegration and the absence of fibrotic tissue (hematoxylin-eosin, 50x) (Muratori, 1979).

3 4 5

6 87 9

Fig. 10 The drawing shows that Pasqualini’s implant can becut at any angle and placed in different cases of edentulism.

101

I too designed a blade, which incorporated into a sin-gle artifact the shapes of Linkow’s original blades (4–9).Since I had immediately purchased the complete seriesof his blades, I could always choose the best one to use,but I noticed that after insertion of the first blade, thechoice for the subsequent implant turned out to bevery limited. Aside from a certain amount of adaptabil-ity that permitted a few minor modifications, after justa few surgeries I had to reorder the missing blades.During complex surgeries that required different bladeshapes, I encountered difficulties even when I had thecomplete series at my disposal because the standard setdid not allow for the use of two blades for incisors,since the set contained just one of each shape. Quite of-ten, from an implant standpoint the bone ridges didnot reflect the conditions that had been determined ra-diographically. More than once I found myself dealingwith cases in which the ridges were too thin right at thepoint where, based on the X-ray, I was supposed toplace the post. Therefore, I had to extend the surgicalgroove either mesially or distally in order to insert anemergency device, which was not as well suited for ex-ploiting all the available space. I faced the same diffi-culties in osteoporotic areas or sockets that had to befreshened, and that the x-ray had not shown. The samedrawback could also arise with Muratori’s universalblades, which he fashioned strictly on the basis of theradiographic images. To avoid these problems, I designed a blade that couldbe adapted to any need via simple on-the-spot modifi-cations. I overlapped the sketches of all of Linkow’s originalblades and obtained a single profile that encompassedthem all. I instructed the laboratory to manufacture avented blade from that solid shape without weakeningthe supporting structure. That way, I obtained the pro-file of a basic “polymorphic” blade, which could beused to easily fashion the blade suitable for all cases. Iadded several landmarks to the main blade, designedto facilitate the immediate creation of the requiredshapes (Fig. 10). The modifications are made with a memory wire cut-ter that permits quick and clear cuts, which can be fin-ished off with a bur.The drawings and images clarify what I have written upto this point, demonstrating the manifold shapes ob-tainable from the polymorphic blade (Figs. 11–19).

Other modifications of Linkow’sblade

The strip blade of Binderman and Shapiro This blade was presented in 1972 and can be sep-

Modifications to the Linkow blade implant VI

Fig. 11 Pasqualini’s polymorphic blade from 1970.Fig. 12 The different combinations obtainable from a single blade inthe upper maxilla.Fig. 13 The combinations for the mandible. On the right, the cutterused to cut the blade.Fig. 14 Blade and cutter.Fig. 15 Case from 1971 with severe edentulism.Fig. 16 Placement of four blades.Fig. 17 Postoperative X-ray (1971). Note the morphology of theblades adapted to the edentulous area.Fig. 18 Healing of the soft tissues and the prepared naturalabutments.Fig. 19 Case treated with a gold-resin prosthesis (1971).

12

13 14

15 16

17 18

19

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arated into different parts in order to yield multiplespecimens (Fig. 20) with slightly different configu-rations (10). The strip blade by Binderman andShapiro cannot be employed for single-tooth im-plants, nor in bone crests that are higher than theblade itself (Fig. 20).

Linkow’s multipurpose bladeProposed by Linkow in 1981 (but not publisheduntil 1992) (11), this blade with one or two posts(Fig. 21) can be modified into 34 different forms,according to the author’s original scheme. Linkowdoes not provide any information other than themanufacturer’s name and address.

Stefano Tramonte’s “genian” blade In some cases, Tramonte also used Linkow’s bladesto rehabilitate very thin bone crests that were unfitfor his screws. In 1982 he reduced the wide set ofLinkow’s blades to a single modifiable artifact, in or-der to obtain implants adaptable to a number ofneeds (12). His blade, which differs from the onedesigned by Binderman and Shapiro in terms ofwidth, posts arrangement and hole diameter, con-sists of a wide vented blade with five large posts(Fig. 22). It can be modified into several shapeswith a variable number of posts (from 1 to 5). Themodifications are made with the same carbide drillsused for the bone grooves. Its posts can also be bent

according to the parallelism required by the pros-thesis. Due to its width and number of posts, Tra-monte’s blade was very suitable for the genian area,which is particularly resistant and capable of with-standing loads that are extensible distally, whenjoined to removable prostheses. After Pasqualini had already announced his newblades with “screwable” abutments, Lo Bello (1979)and Pierazzini (1983) also designed other plateform implants that could be adapted easily to vari-ous anatomical conditions and fitted them with“two-step” abutments. We will discuss this in thechapters that follow.

Giuseppe Foscarini key-shaped blades In 1976 Foscarini published the first report on hiskey-shaped blades in Dental Press, providing addi-tional details in the book The new blades for oralimplantology, published the following year (13).Foscarini’s blades developed the concept of adapt-ability to the various morphological conditions aswell as that of the “least possible extension” and theprinciple of the need to increase the bone sealaround the posts, already stated by Norman Cranin(1971) (14). The author has kindly given us per-mission to quote the most significant passages fromhis book.

I substituted the principle of the least sufficient exten-sion of the blade for that of the maximum extensionpossible in a single case. The new principle reduces thetrauma of the implant operation, the number of per-sons in the operating team, and the rebound effect . . .. This principle seems correct because it is the same asthat used in the normal construction of buildings: thewider the foundations are the better will be the stabil-ity of the buildings. In fact the living bone as a conse-quence of the trauma received during the implant op-eration rejuvenates itself and regenerates new tissueproduced by connective cells, reticulo-endothelial cellsand by the bone’s own cells. We also find in the groove,white and red corpuscoles [sic], neoformed vessels aswell as proteo-glico and lipo-litic ferments [sic].In short we do implants in a bone tissue that at the mo-

Fig. 20 The strip blade of Binderman and Shapiro.

20

Fig. 21 Linkow’s multipurpose blade implant.

21

Fig. 22 Tramonte’s blade implant.

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103

ment is hard, but after a short while will no longer beso. . . . I carefully controlled the data on many hun-dreds of implants year after year and the result of thisresearch was that the tissue removed during the execu-tion of the implant regenerate without hypertrophy. Infact the final hypotrophy was often recognized macro-scopically as a disappearance of tissues into the implantseat. . . . We now realize that the great extension of theblades is not a positive factor but a negative one be-cause the real support of the prosthesis is not the im-planted instrument but the bone in which the implantacts as an intermediary. . . . The consequence of this isthat the blades do not have to be as wide as possible,but instead, as narrow as possible. And this is one ofthe principles upon which were created my “Key-shaped Blades”.

Foscarini designed six blades to handle almost allimplant conditions (Fig. 23). The novelty does notreside in the versatility of the six shapes, but ratherin the design of a thin and buried part, fitted withone or two long extensions, also buried. Only theirfinal portion protrudes toward the outside and itcould be shortened according to the availablespace. Foscarini’s blades are thus not actually short-er in depth, but in the overall metal surface sup-porting the posts. In fact, the blade lacks the entireupper portion, so that the closure of the groove re-quired for their insertion will create a wide bonewall preventing possible resorption along the pros-thetic abutments. Foscarini also advised against de-taching too much of the mucosa when placing hisblades. In this regard, he wrote: “Mucous mem-

brane and bone have a strong correlation and thusthe trauma reverberates from one to the other. Withmy key-shaped blades it is possible, with the mini-mum of proficiency, to perform the same implantwithout exposing a large part of the bone by limit-ing the gum incision to 4 mm, 2 along each side,and by making very narrow gum flaps.”Therefore, he suggested preparing the groove bystarting with a series of holes made by means of along cylindrical bur with a diameter of 1.4 mm anda triangular tip, mounted on a low-speed hand-piece.“This facilitates the second stage which is that oftransforming the series of holes in a groove with theuse of a bur similar to the preceding one.” Theblades were then inserted by gentle tapping on theposts.

Marco Gnalducci’s two-step buried bladeIts retentive portion derives from Linkow’s blades,whereas the prosthetic portion is related toPasqualini’s two-step blade implant (which will bedescribed in detail in Chapter 7). It is a two-step se-mi-buried implant that, due to its morphology, canalso successfully exploit areas with severe bone at-rophy (Figs. 24–26) (15).2

Modifications to the Linkow blade implant VI

2 A.E. Edelman and A.J. Viscido had already designed two-step bladeimplants in the 1970s (16, 17).Fig. 23 Foscarini’s blade implants.

23

Fig. 24 Gnalducci’s implant during placement.Figs. 25, 26 X-rays showing the scarce bony tissuesuccessfully exploited by this blade.

24

25 26

104


References

1. MURATORI G. Tecnica degli impianti a lama e “su mi-sura”. Dent Cadmos 1970;38(6):874-85.2. MURATORI G. Implantation using custom-made bla-des. Dent Cadmos 1971;39(6):879-916.3. MURATORI G. L’implantologia orale multitipo. Bologna:Marino Cantelli Editore; 1972.4. PASQUALINI U. La lama polimorfa. Proceedings of the20th Seminar of the American Academy of Implant Denti-stry; Atlantic City. 1971.5. BERGER S. Report from Europe: the Pasqualini’s blade.Oral Implantology 1971;2(2):158-162.6. IMPERIALI G., PASQUALINI U., PIRAS E. Impianti en-doossei: principi e tecnica d’uso della “lama polimorfa”.Dent Cadmos 1972;5:3-19.7. PASQUALINI U. La lama polimorfa. Proceedings of theCongresso of Blade Implantology; University of Zurich.1971.8. PASQUALINI U. La lama polimorfa. Proceeding of theStomatological Congress of Garda, Italy. 1972.9. PASQUALINI U., IMPERIALI G.M. Practical and theo-retical course on the polimorphic blade. University of Ba-

ri, Italy. June 23-25, 1972.10. BINDERMAN I., SHAPIRO P. A modified form for bla-de type endosteal implant. Oral Implantol 1972 Sum-mer;3(1):19-27.11. LINKOW L.I. The multipurpose blade. Ag. 41, 42 V. Iof: Linkow implant dentistry today. A multidisciplinaryapproach. Padova: Ed. Piccin; 1990.12. TRAMONTE S.M. Impianto a lama universale. Riv EurImplantol 1982;1:7-15.13. FOSCARINI G. Le nuove lame per implantologia ora-le. Firenze: Grafica Style e Grafica Cerbai; 1976.14. CRANIN A.N., DENNISON T.A. Construction techni-ques for blade and anchor implants. J Am Dent Assoc1971 Oct;83(4):833-9.15. LINKOW L.I., MANGINI F. Tecniche implantari ed im-plantoprotesiche - dalle originali “lame di Linkow” all’oste-ointegrazione. Padova: Ed. Piccin; 1997. p. 55-70.16. LINKOW L.I. Implant dentistry today. A multidisci-plinary approach. V. 1. Padova: Ed. Piccin; 1990. p. 35-58.17. VISCIDO A.J. Submerged functional predictive endo-steal blade implants. Oral Implantol 1974 Au-tumn;5(2):195-209.

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CHAPTER VII

T he very intense marketing of the Linkow te-chnique spurred the curiosity of the publicand the demand for implant solutions, de-

spite the justified reservations of academia. Theircritical attitude toward the new method was basedon:1) the fantastical claims of Linkow’s collaborators/

demonstrators of a success rate approaching100%;

2) the consequences of commercial marketing thatleft novices to practice a method advertised asextremely simple, but that instead required cau-tion, surgical skill, insight and extensive pros-thetic experience;

3) the many failures, attributed—without any sci-entific backing—to alleged organic disorders,the lack of hygiene and/or the contamination oftitanium as a result of accidental contact withother metals (chisels, hammers, pliers, etc.);1

4) the absolute lack of experimental trials on thecauses of the failures “of unknown etiology” andthe reasons for the success of analogous im-plants, seemingly placed in conditions identicalto those where failures had occurred.

At the same time, the great advantages of success-fully placed Linkow blades, which increased thechance of solving cases of edentulism untreatablewith other types of implants, could not be underes-timated. I was one of the first to employ his blades,both at the university where I was an assistant andteacher2 at the time, and in my private practice.Since I performed the surgeries merely for experi-mental purposes (charging only to cover the labo-ratory expenses), I was rapidly able to obtain a casehistory large enough to plan a series of studies on

the causes of my failures, which—unlike thoseclaimed by the ads—approached 40%. The first study was designed to assess if our numer-ous failures were attributable to the patients’ healthconditions. The ensuing studies were the result ofexceptional circumstances, which allowed me toconclude that the causes of failure (excepting a fewcases in which a surgical gamble had been taken)resided in the large and long emerging prostheticabutments, and the differences in the static proper-ties of the cancellous and compact integrating bone.

Implants and health conditions

The percentage of my failures with the blade im-plants was slightly lower than my success rate. Thestatement that failures were attributable to the un-stable health of the patients was not backed by anyscientific proof. I never found organic deficienciesserious enough to be considered contraindicationsto implant surgery, which was ultimately a minoroperation.Therefore, I performed checkups on 50 patientswhom I had already treated with blade implants.My collaborators were Antonio Camera, Director ofthe Research and Clinical Analysis Laboratories atthe Ronzoni Hospital of Milan, and later Director ofthe Department of Clinical and Anatomopathologi-cal and Histological Research at the San Paolo Hos-pital, also in Milan, and Gianni Zannini, an outsideprofessional and intern at the Modena Dental Clin-ic.We checked 47 patients (3 did not show up forevaluation). Some of them had stable implants, oth-

THE LONG JOURNEY TOWARD POSTLESS BLADES

Ugo Pasqualini

1 The purchase of expensive titanium instruments was recommended to prevent contamination.2 The Dental Unit of the University of Modena, directed by Arrigo Provvisionato at the time.

Introduction

106


ers were in the initial phases of failure or failurehad already occurred, and yet others had stableimplants alongside implants that were being ex-pelled.Camera (blinded about their implant status) per-formed the same checkup on each subject (Fig. 1).We could not perform other types of investigations,which are normally required nowadays, because atthe time (1971–72) laboratory techniques for de-tecting hepatitis, AIDS (not identified at the time),alpha-beta-gamma globulin ratio and electrolyteswere unknown. Zannini added the data to a large chart, using a plussign (+) to indicate healthy subjects, a different sign(x) for subjects with borderline results betweenhealth and the onset of a pathological situation, anda minus sign (-) for the few whose results were de-cidedly suspect. Beside the results of each checkuphe indicated the positive or negative evolution ofthe implants (Figs. 2, 3). The results, which are veryinteresting, can be summarized as follows:1) the healthy patients, indicated with a (+) sign,

and those whose condition was not as good,marked with the (x) sign, showed the same fail-ure rate;

2) three of the four patients in worse health condi-tions, marked with a (-) sign, simultaneouslyhad stable implants and implants in an expulsivephase in the same mouth;

3) both of the implants of a fourth patient in verypoor health were stable and functioning proper-ly.

Therefore, we were able to refute—with provenfacts—what others claimed in order to explain thefailures of the blades. Based on our research, thosefailures should have been attributed exclusively tosurgical inexperience and/or still-unknown localcauses. Our study was published in 1972 (Fig. 4) and pre-

2

4

Fig. 1 Diagram of the checkups performed by Camera oneach of the 47 implanted patients.

Fig. 2 Section of Zannini’s chart. The status of placedimplants can be seen in the right column (with a blue border).Fig. 3 The results of the checkups of 47 patients. Only 4 ofthem were classified as implant failures (3 partially negative and1 completely negative).

Fig. 4 Original university paper of the research conducted in1972.

ENDOSSEOUS IMPIANTSLABORATORY ANALYSIS

Hemogram Phospholipids Electrophoresis

ESR Triglycerides ASOT

Azotemia Lipemia RF Test

Glycemia Lipidogram CRP

Quick Test Colloid lability Thromboelastographytest

Blood cholesterol Total serum protein Urinalysis1

IMPLANT FAILURES

47

positive check-up 26

check-up within range 17

negative check-up 4

3 – + 1 – –3

107

sented the same year at the Symposium on Prostho-dontics and Applied Gnathology in Mestre (Venice)(1–3).

Reasons for the success or failureof the Linkow blade implant

IntroductionOnce we had ascertained that general health prob-lems had no practical influence on failures, a ration-al study had to be conducted on possible local fac-tors that had been underestimated or were still un-known.My habit of photographing all my cases before, dur-ing and after each surgery was helpful, as it allowedme to separate (a posteriori again!) conditions ofthe implant sites from surgical inaccuracies in orderto explain failed cases (Figs. 5, 6). It was by com-paring the photographic sequence of a resoundingsuccess (divulged worldwide by Linkow) againstthose of the many failures of other implants, placedin seemingly similar conditions, that I was able todemonstrate the different reactions of cancellousand compact bone to the integration of artifactssuch as Linkow’s blades, which had disproportion-ately large emerging posts. Before proceeding todiscuss my final considerations on the local causesbehind the success or failure of the Linkow blade, Iwould like to offer a detailed description of the “re-sounding” success mentioned here, which was cir-culated worldwide and without my authorization todemonstrate the excellence of the new technique.For us, it was merely a case study that allowed usto compare the failures whose etiology was un-known and had yet to be understood.

The caseIn December 1970 Stefano Tramonte referred hismother to me, asking me to attempt the placementof a blade3 in the distal area of the mandible, whichwas too thin for his screws. As already reported inChapter 4, Part III, the lady had been wearing anupper total fixed bridge on three screw implantsthat her son had placed in 1967 (Fig. 7).After detaching the mucosa, I observed a very thinbone ridge, where I was very carefully able to preparea long sagittal groove in order to place a blade witha double post (Figs. 8–10). The ridge would havebeen high enough to allow the placement of a widerblade, but I did not have one on hand. Consequent-

The long journey toward postless blades VII

3 Linkow’s blades had just appeared on the European market.

5 6

Fig. 5 Close-up of the placement of a blade in the lower maxilla.Fig. 6 Another blade in the upper maxilla.

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Fig. 8 The edentulous ridge before flap opening.Fig. 9 Detection of a very thin ridge following flap opening.Fig. 10 The perfect preparation of the surgical groove.

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Fig. 7 Oral X-ray of Tramonte’s mother (1970).

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ly, I employed a narrower and taller implant (Figs.11, 12). The blade was left unloaded for six monthsas my patient was out of town. When I saw her againthe implant was extremely stable, with two postsemerging from a healthy mucosa and well attachedto the underlying periosteum. The clinical checkupof the peripheral seal was performed with a peri-odontal probe, inserted along both posts (Fig. 13).I was unable to restore the adjacent premolar as itwould have been impossible to recover. Since I hadalready performed anesthesia in order to extract thetooth, my patient allowed me to collect specimensof the two mucosal sleeves in direct contact withthe necks of the posts (Figs. 14, 15) and detach themucosa over the top surface of the blade in order tocheck the appearance of the healed tissue. The nor-malcy of the groove reossification over the blade,and the absence of macroscopic gaps in the area incontact with the necks of the posts (where theprobe had halted before the mucosa was detached)confirmed the unquestionable success of the proce-dure (Figs. 16, 17).In Chapter 4, Part III, I noted that I had collectedspecimens around the neck of the Tramonte screws

placed in the upper arch, because the woman want-ed to contribute to a study that would permit com-parison of the behavior of the mucosa in contactwith the neck of the blade posts and that of the mu-cosa in contact with the neck of the self-tappingscrews her son had designed, as well as the gumsurrounding the premolar with periodontitis.4

Tramonte later placed the two fixed prostheses,which remained in service—with no mobilitywhatsoever—until his mother’s death thirteen yearslater.

4 I am still grateful to her and remember her very fondly.

Fig. 11 The deep insertion of a blade from Linkow’s smallest series(1970).Fig. 12 X-ray of the blade right after placement.

Fig. 13 Healing of the soft tissue around the implant posts 6 monthsafter blade placement.

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Fig. 16 The remarkable healing of the bone tissue around theblade testifies to its perfect osseointegration (1970).Fig. 17 The radiographic checkup shows the newly formedbone tissue over the shoulder of the blade.

Figs. 14, 15 Removal of 1 of the 2 mucosal sleeves aroundthe implant posts.

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The histological studyThe mucous specimens were paraffin processed,cut in sections of 4-6 Ì, and stained with hema-toxylin-eosin. The histology of the mucosae collect-ed around the neck of the upper screws and aroundthe lower tooth with periodontitis has already beenreported. Here I refer exclusively to the histologicalexamination of the sleeves of mucosal tissue adher-ing to the neck of the blade implants. Like the specimens collected around the neck of theTramonte screws (Figs. 18, 19), one of them wassectioned horizontally from the surface to the deeplayer of the mucosa. This allowed us to observe theprogressive change in the histological architectureof the mucosa adjacent to the outer area of theposts, which showed all the mucous epitheliumlayers to the deep area where they appeared as asingle layer of germinative cells over the underlyingcorium5 (Fig. 20). The other sleeve, cut parallel tothe main axis of the post (Fig. 21), allowed directcomparison of the histological behavior of the ep-ithelia “external” and “internal” to the neck area(Figs. 22–24). The findings were identical to those


A AB B

BA

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19

Fig. 20 Close-up of a horizontalsection showing the keratin layer,all the epithelial layers (a), and theinternal mucosa in contact withthe implant (b), where the keratinlayer is absent.Corium digitations are virtuallyabsent in the basal layer of theinternal mucosa.

Fig. 21 Example of a verticalcut.

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22 23

5 The histological examination of the many sections, identical for the screw specimens and the corresponding specimen from the neck of theblade, is described in detail in Chapter 4, Part III.

Fig. 18 Diagram of one of the horizontal sections obtainedfrom the deep area of the mucosal sleeves surrounding theimplant post.Fig. 19 Some of the 2400 histological specimens. 24

Fig. 22 The even thinning of thelayers of the internal epithelium,going from the external layertoward the epithelial attachmentarea (hematoxylin-eosin 200x).Fig. 23 The last cells of thegerminative layer over the dermis(hematoxylin-eosin 400x).Fig. 24 Section of a healthyperiodontal pocket surrounding anatural tooth.

a

b


of similar sections of healthy gum pockets in con-tact with the neck of natural young and stable teeth.This research demonstrated that the choice be-tween the two systems (Tramonte’s self-threadingscrews versus Linkow’s blades) should be motivat-ed only by considerations of the shape best suitedto the morphology of the edentulous areas to betreated, a concept that could be extended to anyother implant method using biologically inert allo-plastic materials. The reasons for failures occurring under conditionsthat were seemingly identical to those whereLinkow’s blade underwent remarkable osseointe-gration were yet to be understood (4–9).

The causes for failures of unknownetiology

The remarkable osseointegration of the case I havejust described proved that blade implants were of-ten able to treat many cases of edentulism betterthan traditional prostheses.Nevertheless, the causes of the many failures ofidentical implants, placed with the same precau-tions and using the same surgical technique, werestill unknown. The influence of early or delayedloading, which seemed to produce almost identicalsuccess and failure rates, was also unknown. Once the possibility of the negative influence ofgeneral health deficiencies had been ruled out, westill hoped to identify the unknown factor—un-questionably local—that influenced successes andfailures alike. It was extremely helpful to have thephotographic records of all previously treated cas-es, checked before, during and after surgery, andduring the prosthetic phase. I then started to review the first slides of the failuresof the early-loaded implants, followed by those ofimplants that were left unloaded for severalmonths.The first verification—early loading—confirmedthe constant success of blades that had been placedand splinted to natural stable abutments, while thefailure of the blades used as terminal abutmentswas extremely frequent (Figs. 25, 26). Early load-ing seemed to have a positive influence in the post-operative splinting of the implants placed betweennatural teeth, while it appeared to be harmful forthe early splinting of the terminal implants. There-fore, the immediate loading recommended byLinkow favored the osseointegration of intermedi-ate implants splinted on both sides to two stablenatural abutments, while it negatively affected the

osseointegration of terminal implants, which cycli-cally underwent compression by local occlusalforces followed by immediate release due to theelasticity of the prosthetic metal. The next examination, conducted by reviewing theoriginal conditions of the implants left unloaded forseveral months after surgery, confirmed that successtended to occur with thin ridges where there isabundant compact bone, while failures tended tooccur with wider ridges, which have abundant can-cellous bone (Fig. 27).

Fig. 25 A blade placed between two natural abutments,which acts as “stress breaker” for a long bridge.Fig. 26 A blade supporting a bridge.

27

Fig. 27 Left: compact bone right: cancellous bone.

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25

The comparison between the osseointegration ofthe implant placed in Mrs. Tramonte’s thin crestbone and the expulsion—resulting in tissue loss—of an implant placed in a similar groove of a widerbone crest, was very interesting (Figs. 28–31). With


Fig. 28 Surgical groove in an edentulous area with abundantcancellous bone.Figs. 29, 30 At 3 months, mobility and loss of the blade withsevere damage of the including bone tissue and disarray of thehistological pattern.Fig. 31 Histological proof the inflammation and morphologicaltissue degeneration of the tissue surrounding the implant.

Fig. 32 The arrows point the axial and transverse forces onsupporting tissues of different morphology.Fig. 33 Compact bone.Fig. 34 Cancellous bone.

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these unloaded implants, the causes of failure werethus attributable to the different structure of thebone sites (Figs. 32–34), bearing in mind that thecrucial precondition for the reparative osteogenesisof any bone wound is a quiescent phase.In fact, the fractured ends of long bones are immo-bilized with casts or orthopedic plates until the os-teoblasts have matured into osteocytes and calciumsalts have been deposited, contributing to the finalmineralization of the healing tissue.I finally realized that the chief cause of almost allthe failures observed with the blade implant wassimply the lack of quiescence during the reparativeosteogenesis phase.

Surgical integration, biological integration or rejection of the blade implantsAfter surgical creation of the inserting grooves, theblades placed by percussion achieve natural stabi-lization within the rigid walls of compact bone. Incancellous bone, however, they are stabilized onlytemporarily by the compression of a few fracturedtrabeculae, which are then resorbed before biologi-cal osseointegration begins (Figs. 35, 36).Therefore, the implants inserted into cancellous

bone are in an increasingly softer medium that isgradually resorbed by macrophages and osteoclasts,leaving them virtually afloat in an empty space andgreatly disturbed by the continuous stress exertedby the posts outside their buried structures. The stability of the blades placed in thin ridges re-lies on the rigid walls of the compact tissue of thetwo close cortical walls, where resorption, which isfar more moderate, does not affect the state of qui-escence required for the progression of osseointe-gration. Stabilization within the cancellous bone isvery different, since the quiescent state essential forcompleting bone integration following ischemiaand resorption of the fractured and compressed tra-beculae is instead highly jeopardized.Even if the blades placed in the cancellous bonehad been left unloaded during reparative osteogen-esis, they would nevertheless have suffered seriousdamage due to the continuous lateral stresses exert-ed by the tongue on the external abutments duringthe last phase of oropharyngeal swallowing, irre-versibly impairing their biological integration (Figs.37, 38).

ConclusionsThe above-mentioned studies on implants checked aposteriori, confirmed that the etiopathogenesis of myfailures was ascribable to the traumatic stress exerted

Fig. 35 Blade placed by percussion onto the cancellousbone.Fig. 36 The transverse stress exerted by the tongue duringswallowing can mobilize the implant.

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Fig. 37 Close-up of the stress exerted by the tongue on theblade posts.Fig. 38 Overloading in centric occlusion during the last phaseof swallowing.

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on the bulky posts outside the submerged portionsof the blades. The 40% failure rate, which was slight-ly lower than my success rate, was due to the fortu-nate combination—for which I can take no credit—of having treated cases of medium difficulty withmore favorable outcomes. Therefore, I decided to re-place the bulky external posts with structures thatemerged only slightly, but could nevertheless be usedto join the blades to the prosthesis after inclusive os-teogenesis was completed (Figs. 39, 40).

References

1. PASQUALINI U., CAMERA A., ZANNINI G. Risultati di47 check-up di controllo in 47 soggetti portatori d’impian-ti. Giornale di Odontostomatologia 1972;3:14.2. PASQUALINI U. La relativa importanza dello stato di sa-lute nel determinismo del successo o dell’insuccesso degliimpianti a lama. Proceedings of the Simposium on Prostho-dontics and Applied Gnatology. Mestre (Venice): Ed.A.I.I.A.; 1972.3. PASQUALINI U. Impianto protesi e gnatologia applicata.

Proceedings of the National Congress of Alloplastic Im-plants. Mestre (Venice): Ed. A.I.I.A.; 1972.4. CAMERA A., PASQUALINI U., ANNARRATONE P. Re-perti anatomo-patologici di sette impianti a lama post mor-tem. Associazione Italiana Impianti Alloplastici 1972;1:10-6. 5. PASQUALINI U. Subcortical bars: principles and technicof a new endoossal implantation. Personal technic. Preven-tive note. Dent Cadmos 1972 May;40(5):672-93.6. CAMERA A., PASQUALINI U. Comportamento dell’epi-telio umano intorno ai perni uscenti degli impianti endos-sei. Associazione Italiana Impianti Alloplastici 1972;3:12-7.7. PASQUALINI U. Ricerche isto-anatomo-patologiche inimplantologia. Associazione Italiana Impianti Alloplastici1972;5:40-7.8. CAMERA A., PASQUALINI U. Impianti endossei: istolo-gia comparata della zona del colletto in un dente naturale,due monconi di Linkow e tre viti di Tramonte. Associazio-ne Italiana Impianti Alloplastici 1972;6:15-20.9. CAMERA A., PASQUALINI M.E., TRAMONTE S. Istolo-gia comparata dei tessuti della “zona del colletto” di un den-te naturale e di tre viti di Tramonte. Doctor Os 2005 nov-dic (suppl.);16(9):1-10.


Fig. 39 Removal of the external post. Fig. 40 The absence of external stress permits reparative osteogenesis in a state of quiescence.

39 40

TREATISE OF IMPLANT DENTISTRY CHAPTER VIII

All the two-step vented basket implants testedon dogs ten years earlier (1962) gave excel-lent results, because each one kept the ba-

skets in a quiescent state during the critical phase ofreparative and integrating osteogenesis. Pasqualinithus decided to fit the blades with very short threa-ded emerging posts to prevent external mechanicalstress on the submerged structures (Fig. 1).

There was nothing to prevent him from employinginternal threads that would be completely shieldedby the mucosa, except for the inconvenience of per-forming another operation -complicated and oftenpointless- to connect the abutments. Therefore, heremoved the posts from the polymorphic blade inorder to thread a small portion of the neck to con-nect the prosthetic abutments at a later date (Figs.2, 3). The smooth portion of the implant neck,which emerged 3 mm from the top of the blade,had to be completely buried within the bonegroove; the threaded portion that grazed the exter-

nal mucosal surface measured an additional 2 mm.Thus modified, the blades would not interfere withthe quiescent state of reparative osteogenesis, al-lowing subsequent risk-free loading (Figs. 4, 5).In August 1972, following the positive outcomes ofall the cases treated using this approach in his pri-vate practice and at the Dental Department of Uni-versity of Modena, Pasqualini published an article

Introduction

THE POLYMORPHIC TWO-STEPBLADE IMPLANTS

1

Fig. 1 Original drawing of Pasqualini’s blade.

2 3

Fig. 2 Blade, temporary Teflon abutment, and definitive abutment.Fig. 3 The temporary healing abutment in Teflon models themucosa according to the profile of the definitive abutment, whichwill be screwed when osteogenesis is complete.

4 5

Fig. 4 Removal of the healing abutment.Fig. 5 Definitive abutment onto which the crown will be fitted.

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titled “Impianti endoossei: la protezione dell’osteo-genesi riparativa con la metodica del ‘monconeavvitato’. Tecnica personale. Nota Preventiva” inDental Cadmos, no. 8 (1) (Fig. 6). He wrote:

The best conditions for rapid healing of the surgicalwounds required for implant insertion, with formation ofnew bone around, above and through the vented arti-facts, occur only when the implants are completelyburied, with no communication with the external envi-ronment. The reason is not merely to avoid the dreadedbut actually nonexistent risk of microbial contamination,but also to eliminate the lever arm represented by the ex-ternal posts, which can transmit dangerous mechanicalstress to the buried portions, subjecting them to contin-uous mobilizations that can jeopardize the evolution ofthe integrating osteogenesis. Reparative osteogenesis willpermanently stabilize only the inclusions protected fromexternal mechanical stress during the healing phase. Giv-en these considerations, which are based on my recentstudies on humans as well as prior testing on animals (2),I came up with the idea of a “two-step” implant techniqueon screwable abutments, which are composed of:1) an endosseous portion (which can have differentshapes: basket, truncated cone, screw, blade, etc.) fit-ted with a very short threaded emerging post;2) a prosthetic abutment that can be screwed onto itonce the biological inclusion of the buried portion hasbeen completed.

Pasqualini was also granted patents in Italy, GreatBritain and the United States for his polymorphicblade and the protective principle of reparative os-teogenesis, applicable not only to his blade but al-so to any other type of implant with “internal” or“external” screwable abutments following the com-pletion of osseointegration. With his patent appli-cations, he was simply protecting himself againstthose who might “forget” to recognize his scientificauthorship, as invariably proved to be the case.

The anatomopathologicaland histological behaviorof the integrating tissue of bladeimplants with screwable abutments

IntroductionThe first two anatomopathological and histologicalexaminations were performed on two polymorphicblades with screwable abutments that had to be re-moved due to fracturing of the neck connecting themto the prosthesis. Consequently, they were explanted

together with a portion of the integrating tissue.The fractures occurred at the transition area be-tween the smooth portion of the neck and the endof the short threaded part at the base of the exter-nal abutments of the first series of blades.The critical area was represented by the last portionof the thread, which remained outside the lower-most portion of the screwable abutment. Followingthese episodes, the external abutments were length-ened to cover an adequate segment of the smoothportion of the neck, which caused no further prob-lems because there were no longer any areas thatwere more susceptible to fracturing. The explantation of the two polymorphic bladeswith the adhering integrating tissue made it possi-ble to verify that the osseointegration of the newtwo-step implants was decidedly better than thatobserved with the majority of blades with fixedposts. Interposed between the newly formed inte-grating bone and the metal, the latter almost alwayshad a layer of fibrotic tissue that mobilized themslightly, although stabilization was good enough forplacement of a temporary prosthesis (3).The third histological examination was performedusing the technique invented by Karl Donath, Di-rector of the Institute of Oral Pathology at the Uni-versity of Hamburg, on the tissue in contact withthe two-step blade, excised in toto by PierangeloManenti of Bergamo.

Description of the cases

Case one - Polymorphic blade with a screwableabutment placed in a wide bone crest and loa-ded five months later with a bridge connected tothe canine.The blade, used as a distal abutment, remained sta-ble for two years until the threaded post fractured,making it unusable. At the eight-day checkup, the

The polymorphic two-step blade implants VIII

6Fig. 6 The original 1972publication.

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short residual post was already almost completelycovered by mucosa. The very minor solution ofcontinuity (Fig. 12) was created by the probe usedto check the pocket depth along the residual por-tion, which measured about 1 mm. The flap opening showed a new bone layer abovethe blade and around the residual post. The explan-tation was performed so as to include as much ofthe tissue adjacent to the blade as possible. Os-seointegration is readily visible above, through andbelow the blade implant. The specimen, fixed in 10% formalin, was given toAnthony Ricciardi and Angelo Chiarenza of NewYork, who attended the procedure, so that theycould examine it with a scanning microscope,which was unavailable in Italy at the time (1973).Ricciardi published the results of the specimenanalyses in Quintessence International Dental Di-gest, No. 1, Vol. 8, in an article titled “A two-year

report of a human bone block” (4). The commentsto the pictures of the magnified details published inthe journal note that Pasqualini’s implant demon-strated the perfect bone adaptation to the structuresof his polymorphic blade with a screwable abut-ment: the virtual void between the bone tissue andthe implant, at 1500 magnification, is less than10μ. Ricciardi also noted the perfect apposition ofbone around the metal structures, without the in-terposition of fibrous tissue (Figs. 7–17).

Case two - Pasqualini’s polymorphic blade with ascrewable abutment, placed in a hemimandibleand loaded after three months of quiescence.It remained stable and in service for five years un-til the neck connected with the prosthetic abutmentfractured.The specimens were collected so as to preserve partof the integrating bone. The pictures are very rep-

Fig. 7 Correct placement of a Pasqualini blade. Fig. 8 Healing of the mucosa around the temporary abutment.Fig. 9 Left: close-up of the healed mucosa; right: definitive abutment.

Fig. 10 Blade-canine bridge. Fig. 11 Decementation of the canine caused a stress fracture of the implant neck.Fig. 12 Intact mucosa covering the fractured blade. The arrow indicates a very small solution of continuity.

Fig. 13 Flap detachment and view of the osseointegration of this blade. Fig. 14 Bone-implant block section. Fig. 15 The specimengiven to American colleagues. Fig. 16 Scanning microscope analysis. Fig. 17 The original 1977 publication.

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resentative, and demonstrate that these types of im-plants undergo remarkable and very effective os-seointegration even when placed in cancellousbone, without the interposition of fibrous tissue(Figs. 18-24) (5).We would like to take this opportunity to com-memorate the late Carlo Zerosi from the Universityof Pavia, who performed the microscopic sectionsand the photographic magnifications, and provideddetailed descriptions.

Case threeCredit for this study goes to Manenti, who explant-ed a postless polymorphic blade that was partiallycompromised by violent trauma, which damagedpart of the bone crest where it had been placed nineyears earlier. Bone resorption following traumacomprised a portion of the bony wall adjacent tothe blade, which nevertheless was still stable. Ma-nenti felt that it was best to remove the blade andreplace it with another implant. In order to proceed with the sophisticated exams al-lowing the concomitant observation of both the im-planted metal and the integrating tissues, he ex-planted the blade together with an extensive por-tion of tissue, also removing a section of the maxil-


Fig. 18 Block section of a blade placed in a hemimandible. Fig. 19 Detail of an osseointegrated blade.Fig. 20 Another close-up. Fig. 21 The specimen sent to Carlo Zerosi. Fig. 22 The histological examination proves complete

osseointegration without the interposition of fibrous tissue. The left arrows show the neoformation of bone with abundantmucopolysaccharides (thus showing greater stain uptake). Right: old bone tissue. The different orientation of the lamellae of the newly formed

bone is evident, showing a number of osteocytes in their respective niches (hematoxylin-eosin – 240x). Fig. 23 Detail of a histologicalsection showing the circumferential area corresponding to the blade arm (toluidine blue – 15x). Fig. 24 Higher magnification of the

previous figure. Note the clear boundary between the new bone and the peripheral bone, in which two intact Havers channels are visible close to the blade arm (hematoxylin-eosin – 130x).

18 19 20 21

22 2423

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26

Fig. 25 Upper maxillary bone-implant block section. Thethree upper arrows indicate the floor of the maxillary sinus.Fig. 26 Opposite side of the block section.

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lary sinus floor that had been in contact with theimplant (Figs. 25, 26).The specimen was sent to Hamburg to Donath, theinventor of this examination technique. Followinga special preparation (resin inclusion, etc.) he sec-tioned the specimen as per our specifications. Tolu-idine blue was employed for the staining of all spe-cimens.

Description of the studyEach of the eight illustrations with the details of thesections shows the constant and perfect direct ap-position of newly formed bone to the metal surface,with no interposition of fibrous tissue. The higher magnifications confirm that bone apposi-tion occurred by means of “ankylosis of the integrat-ing bone”, adapting itself in a mirror-like fashion toeven minimal irregularities of the metal surfaces.The details of these extraordinary findings are de-scribed in the captions of the corresponding figures(Figs. 27-34).

Improvements to the polymorphicblades with screwable abutments

1) The prosthetic “osteoprotective” abutment.Today, nearly all the two-step implants employ thesame prosthetic abutment that Pasqualini devisedfor the polymorphic blade (1972) (6, 7). Since on-ly a few of the many imitators are aware of the rea-sons for its particular profile, which protects thejunctional area between the periosteum and theneck of the implant, we will briefly describe itsprinciple (Fig. 5). Most of the fixed implant abut-ments of the 1960s and 1970s (screws, blades,etc.) protruded with a sort of “undercut” from asmooth thinner neck that joined them to the sub-merged portion. This encouraged the deposition ofperishable organic residues that could irritate theunderlying area comprising the periosteal seal ofthe implant neck, which often recessed as a result,causing mucositis and/or marginal peri-implanti-

27 28 29 30

31 32 3433

Fig. 27 Histological image of the block section (15x). Fig. 28 Detail of the osseointegration at the base of the shoulder of theblade (250x). Fig. 29 A very high magnification shows how the compact bone is apposed to the “flaws” of the implant titanium material. Fig. 30 The arrow points the lowermost blade portion in contact with the floor of the maxillary sinus.

Fig. 31 Close-up of the previous image showing that the peri-implant bone after 9 years of loading is compact,and apposed to the metal surface. Fig. 32 Another section of the blade implant. The arrow points to the area

magnified in the following image. Fig. 33 The peri-implant bone appears as a compact and well-mineralized mass (250x). Fig. 34 Higher magnification of the previous image, making it possible to see

the symmetrical pattern of the lamellar tissue.

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tis. Pasqualini designed the protective profile of thescrewable abutments by replicating the crownshape of the natural teeth, which have a protectivecingulum that narrows at the neck and shifts thebolus outside the junctional area (Figs. 35-37).

2) Temporary healing abutment made of Teflon andtitanium.Once integrating osteogenesis was complete,screwing the abutments to the short threadedposts of the polymorphic blades was not an easytask. During the healing process, the mucosa be-came firmly attached and had to be removed bymeans of minor but complicated surgery (Fig. 38).Consequently, small temporary Teflon abutmentswere manufactured with the same shape as thelower portion of the future abutments. The tempo-rary abutments were screwed to the threaded postsright after blade placement. As it healed, the mu-cosa modeled itself to their exact profiles, whichwere identical to those of the lower portion of thefuture abutments. The latter were then screwed inwithout painful compression of the mucosa or theneed for any surgical preparation (Figs. 3, 4, 8, 9).The temporary abutments were kept in placethroughout the reparative osteogenesis period, andwere removed only when they had to be replacedby the abutments. The Teflon temporary abut-ments can be replaced with titanium abutments,which induce the same mucous behavior.

3) Removal of excess cement from the prostheticabutments.Screwing the abutments securely to the threadedposts is not always enough to prevent them frombecoming unscrewed. Consequently, it is advisableto use an insoluble adhesive to keep the counter-threads firmly in place. Oxyphosphate cement isnot strong enough, since it crystallizes and be-comes friable, detaching itself from the metal sur-faces. Resin and glass ionomer cements are moresuitable. Forced in by the screwing, the excess ma-terial can end up below the abutments, going along

the smooth neck and damaging its junctional areawith the surrounding periosteum. The abutmentsof the two-step blade implants are thus completelyvented by the internal thread, allowing the cementto spill over and outside the abutments (Fig. 39).

4) Abutment parallelism.The implant’s placement direction, which is con-ditioned by the orientation of the edentulousridge, can result in lack of parallelism of the abut-ment, as in the example shown in the following il-lustrations. The threaded neck of the blades, re-moved after the placement test, can be bent easilyto a more suitable angle for the future prostheticcrown (Figs. 40-49).

5) Ergonomics and convenience of the polymorphicblade implant. The following illustrations show many of the dif-


38

39

Fig. 38 The healed mucosa is strongly adherent to the blade’s threaded post.

Fig. 39 The abutment’s internal hole allows for cement spillage.

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6) Geyer’s cogwheel.Geyer’s cogwheel is not actually a blade modifica-tion, but a drill that simplifies and improves thepreparation of the surgical groove where the bladeswill be housed. The cogwheel is a drill for low-speed contra-angle, made of a cogged disk that is 1mm thick and has a diameter of 5 mm; it is em-ployed to make a rapid initial groove in the corti-cal bone, which will be deepened by a fissure bur1.The clean and accurate incision is shown in Figure56, whereas a groove made exclusively with fissureburs will never be as neat, as the operator’s possi-ble unsteadiness or the patient’s movements canenlarge the groove more than necessary (Figs. 55-57). The drill was already used by dental laborato-ries for cutting plaster casts. Arno Geyer of Ham-burg was the first to employ it in implant surgery

40 41

44

45 48 49

42

43

46 47

Fig. 40 A double blade was used to make an implant shape suitable for placement in an edentulous area due to the loss of the upper lateralincisor. Fig. 41 The cutter used to create the different blade shapes. Fig. 42 Surgical flap. Fig. 43 Blade placement.

Fig. 44 Radiographic checkup. Fig. 45 The definite abutment is not parallel with the adjacent teeth. Fig. 46 After removing theimplant from its surgical site, the abutment can be set parallel and reinserted into the existent surgical opening

Fig. 47 Implant properly placed with the abutment parallel to the adjacent teeth (left); the temporary healing abutment (right)Fig. 48 Healing of the soft tissues at 3 months. Fig. 49 The single definitive crown.

ferent shapes that can be obtained easily from thepolymorphic blade with a screwable abutment.The implant was originally designed as a double-post blade, but is advisable to divide it and, if nec-essary, place the two sections into two contiguousgrooves. This makes the procedure less complicat-ed and facilitates correct penetration of the bladebelow the cortical surface. The next set of photo-graphs demonstrates that a few basic shapes canyield a sufficient number of blades for the rehabil-itation of completely edentulous ridges (Figs. 50-54). Despite many years of use and positive resultswith these blades, the reader should note that theirosteoprotective principle does not automaticallyexempt them from failure caused by inexperience,surgical gambles and/or the placement of occlusal-ly imbalanced prostheses.

1 The piezoelectric scalpel was recently introduced, making it possible to create a clear-cut surgical groove, fully respecting innervation (e.g. themandibular alveolar nerve).

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to facilitate preparation of the implant grooves, andit was thus named after him (8). When the cog-wheel is inserted up to the mandrel, it automatical-ly maintains the cutting direction because it restson the crest while it cuts, thus counterbalancingmovements caused by other types of stress. Al-though it is used with a low-speed handpiece, itshould be water-jet cooled. A drill with a similarconcept had already been designed and used by Se-bastiano Lo Bello for his inverted-T implant (9).

The static superiorityof polymorphic blades withscrewable abutments

The stability of the two-step2 single-tooth front im-plants - unlike the implants connected to otherabutments - is assured only by the statics of theirbiomechanical characteristics, without any furtherstabilization. As a result, we have chosen two very

edifying examples3 to demonstrate the importanceof reparative osteogenesis with the screwable abut-ment technique (10-13). Single-tooth implants, os-seointegrated in a quiescent state, always allow sin-gle loading without splinting to the adjacent teeth.Let’s not forget that the life of these implants is tiedto maintaining the static and dynamic occlusal bal-ance, as shown in the following illustrations.

Case oneSingle-tooth blade implant replacing an upper cen-tral incisor, placed in a sixteen-year-old boy. It hasbeen in place for 36 years with no connection to theadjacent teeth. Placed in 1972, it was left without aprosthetic abutment for three months. Once theTeflon abutment was removed, the definitive pros-thetic abutment was screwed in and the porcelaincrown cemented. Checked again after six years, thecase was presented in Milan at the National Con-gress of the Italian Dental Association in 1978, andpublished in national and international journals(14-17). The photographic and radiographic


50

55 5756

Fig. 50 Using the cutter, 6 implant shapes and 6 prosthetic abutments can be made from 3 blades. Fig. 51 Radiography of the 3blades made into 6 implants. Fig. 52 Right:Teflon abutments. Left: threaded abutments and healthy mucosa. Fig. 53 The same

procedure is performed in the upper maxilla. Fig. 54 Left: definitive abutments in situ. Right: the two gold-porcelain prostheses.

Fig. 55 Geyer’s cogwheel. Fig. 56 The cogwheel permits clean cuts of the bone surface.Fig. 57 Correct placement of a blade in this very thin edentulous ridge.

51 52

53 54

2 The terms “blade with screwable abutment” and “two-step blade” are used interchangeably, as the two are equivalent.3 Pasqualini’s private practice has a photographic archive composed of no less than 23,000 slides, with 293 documented cases of single-tooth implantations.

58 59 60 61

66 67 68

69

62

70 71 72

64 6563

Fig. 58 Loss of the upper central incisor in a sixteen-year-old boy (1972). Fig. 59 Flap detachment and creation of the surgical groove.Fig. 60 Single-tooth implant obtained from the basic postless polymorphic blade, immediately after placement. Fig. 61 Appearance of thehealed mucosa surrounding the protective Teflon abutment at 3 months. Fig. 62 Definitive abutment (left); the single gold-porcelain crownimmediately after placement (right). Note the boy’s beardless chin (1972). Fig. 63 Postoperative X-ray. Fig. 64 Radiographic checkupafter 27 years. Clear absence of any type of resorption of the integrating tissues (1999). Fig. 65 The gold-porcelain crown after 27 years

(left); the traction test with 5 orthodontic elastics demonstrates the stability of this implant (right). Fig. 66 The smile of the patient, nowadult. Fig. 67 The patient’s mouth in centric occlusion. Fig. 68 Canine disclusion prevents dynamic premature contacts on all the front

teeth (left); likewise, the front teeth are protected during contralateral canine disclusion (right). Fig. 69 Follow-up at 36 years (2008).Fig. 70 The radiographic checkup does not show any change in the peri-implant bone. Fig. 71 Clinical appearance after 36 years.

Fig. 72 The radiographic magnification shows the formation of a “lamina dura” (arrows) around the implant.

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checkups, performed 36 years later, confirm theperfect osseointegration of the single-tooth implant.The changes in the patient’s face are quite interest-ing, as he was beardless when the implant wasplaced (he was 16)4, and now he shows the passageof time! Respect for static and dynamic occlusion,

as well as protection of reparative osteogenesis,contributed to the life span of this implant, asdemonstrated by the last illustrations (Figs. 58-72).

Case twoSingle-tooth premolar implant (Figs. 73-95).

4 According to current international protocol, it is advisable not to place implants in male patients under the age of 18, due to the risk of shifting withskeletal maturation.

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73 74 75 76

81 82

83 8485

77

86 87

79

80

78

Fig. 73 The implant shape chosen for the second case of single tooth loss of an upper left premolar. Fig. 74 Loss of the firstupper left premolar (1988). Fig. 75 The flap opening confirms the presence of a very thin ridge. Fig. 76 First phase of the

surgical groove preparation using Geyer’s cogwheel. Fig. 77 Groove deepening with the 700 XXL fissure burFig. 78 Clean surgical groove for the placement of an “osseointegrable” Pasqualini blade.

Fig. 79 The correctly placed implant: the shoulder of the blade must be set about 2 mm below the edentulous ridge surface (left).Right: the insertion axis of the implant prevents parallelism of the abutment with respect to the adjacent teeth.

Fig. 80 The implant is removed (left), and its non-parallel abutment is bent with a clamp and universal pliers to achieve correctparallelism (right). Fig. 81 Verification of parallelism. Fig. 82 Left: unscrewing of the definitive abutment. Right: X-ray.

Fig. 83 Suture and screwing of the Teflon healing abutment (left); healing at 3 months after surgery (right). Fig. 84 Removal ofthe Teflon abutment (left), and screwing and cementation of the definitive prosthetic abutment (right). Fig. 85 “Chamfer” finish-line

preparation of the abutment with a fissure bur mounted on a high-speed handpiece, water-cooling jet (left), and placement of theretracting cord before impression taking (right). Fig. 86 Impression with Impregum following retraction cord removal (1988).

Fig. 87 Three months after surgery we placed a temporary crown shaped to guide the healing process of the soft tissue to recoverthe proper aesthetic morphology of the gum. Fig. 88 Definitive gold-porcelain crown.

88

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The figures and corresponding captions under-score the fact that, despite the very thin residualcrest bone and its anomalous inclination, the useof a single-tooth two-step blade allowed rehabil-

itation of the edentulous area.

Case threeIllustrated in Figures 96-103 (1987-2007).

96 97 98 99

100 101 102 103

89 91

92 93 94 95

90

Fig. 89 Cementation and check of static occlusion. Fig. 90 Detail of the left and right lateral canine disclusion.Fig. 91 X-ray of the finished case (1988). Fig. 92 The face of the young patient with the blade implant

and the artificial crown (1988). Fig. 93 Ten-year follow-up (1998).Fig. 94 Detail of the static occlusion and the artificial crown. Fig. 95 X-ray of this single-tooth implant in static

and dynamic balance (1998).

Fig. 96 Severe edentulism of both arches (1987). Fig. 97 Healing of the mucosae around the lower maxillary implants. In this case, twotypes of implants were used: blades for the distal areas and single-step screws for the front area.. Fig. 98 The upper maxilla was treated

with two of Pasqualini’s polymorphic blades and a Linkow blade, with preparation of residual natural abutments. Fig. 99 Appearance of themucosae around the Teflon healing abutments of the polymorphic blades.

Fig. 100 Gold-porcelain fixed complete bridge at the time of cementation (1987). Fig. 101 Radiographic checkup.Fig. 102 Twenty years later the upper bridge was removed and the natural abutments were prepared again for a new prosthesis. Note the

beautiful radiological appearance of the integrating bone of these implants, which had been in service for as many as 20 years.Fig. 103 The finished case (2007).

125

Case fiveIllustrated in Figures 108-116.This set of photographs clearly shows that the use of


108

109

110 111

112 113

104

105

106

107

Fig. 104 Placement of two polymorphic blades in a verythin ridge.Fig. 105 Correct placement.Fig. 106 Healing at 3 months.Fig. 107 Panoramic X-ray of the finished case, also treatedwith screws and pins.

Fig. 108 Edentulism and atrophy of the distal mandibularareas (1992).Fig. 109 Placement of the right blade.Fig. 110 Another blade is placed on the left side.Fig. 111 Healing of the soft tissues.Fig. 112 Close-up of the threaded post and the mucosalprofile created by the healing abutment.Fig. 113 Natural abutments and implants before placementof the definitive crowns.

Case four Illustrated in Figures 104-107 (1988-2006).

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polymorphic two-step blades allows surgery on verythin and atrophic ridges without the need for graftingprocedures. This also assures a short healing period,thus rapidly rehabilitating masticatory function,which represents a great benefit for the patient. The cases presented here, with follow-ups at 20,18, and 15 years, were performed by PierangeloManenti, who also employed screws and stabilizingneedles5.

Cases six and sevenThese last two examples show that the distal at-

rophic mandible area is the elective edentulous sitefor Pasqualini’s two-step polymorphic blade (Figs.117-120).

114 116

Fig. 114 Gold-porcelain prosthesis. Fig. 115 X-ray (1992). Fig. 116 The same case 15 years later (2007).

Fig. 117 Severe horizontal atrophy after augment graftingfailed. The case was solved with a polymorphic blade.Fig. 118 Radiographic verification. Figs. 119, 120 The seventh case.

117

118

120

119

5 The topic will be examined in Chapter 11.

115

127

The biomechanical principleof mini-blades in thin ridgesBlade placement in very deep grooves of thin andmainly compact ridges can be dangerous (Figs.121-123) (19-23). The risk is represented by the fragility of the groovewalls, which can shatter when the blade is tappedin. Consequently, a mini-blade was designed forplacement into thin ridges; its top surface is 1.3 mmthick. In addition to having a sufficient functionalextension, it can also be completely buried in 10-mm-deep bone grooves. Due to the remarkable stability provided by thecompact and thin walls, the blades have a short de-finitive abutment. The 4-mm abutment emergesabout 2-3 mm from the sutured gums and is thussubjected to only minimal external mechanicalstress. To facilitate the retentive linear bone groove prepa-

ration technique, the first incision is made using theGeyer’s cogwheel, followed by groove deepeningwith a 700 XXL bur (long) that has reference notchfor the required depth. Mucosa detachment, groovepreparation, mini-blade placement and suture takeonly a few minutes to complete. During healing, the mucosa retracts and stretches,thus freeing the entire abutment by 4 mm, leavingthe underlying portion completely buried and os-seointegrated. Although these mini-blades have ashort (4 mm) definitive prosthetic abutment, whenplaced in compact bone they enjoy the same advan-tages offered by the blades with a screwable abut-ment.

References

1. PASQUALINI U. Endosseous implants. Protection of repa-rative osteogenesis with the “screw stump”. Dent Cadmos1972 Aug;40(8):1185-94.2. PASQUALINI U. Reperti anatomo-patologici e deduzionicliniche chirurgiche in 91 impianti alloplastici in 28 animalida esperimento. Riv It Stomat 1962;12:1128. 3. WEISS C.M. Tissue integration of dental endosseous im-plants: description and comparative analysis of the fibroosse-ous integration and osseous integration systems. J Oral Impl1986;12(2):169-214.4. RICCIARDI A. A two year report of a human bone block.Quintessence Int Dent Dig 1977 Jan;8(1):9-15.5. PASQUALINI U. Le patologie occlusali. Eziopatogenesi eterapia. Milano: Masson; 1993. p. 20-21.6. PASQUALINI U. Corso di implantologia a lama. ClinicaOdontoiatrica Università di Zurigo. 1971.7. PASQUALINI U. Endo-osseous implantations: clinical, hi-stological and anatomic-pathological studies. Dent Cadmos1971;39(6):886-90.8. VERNOLE B., GEYER A., PASQUALINI U. Endosseousblade implantation. Preparation of the surgical sulcus withGeyer’s cogwheel. Author’s personal method. Minerva Stoma-tol 1973 Nov-Dec;22(6):266-8.9. LO BELLO S. Implantologia orale. Padova: Ed. Piccin;1976. p. 203-320.10. MANENTI P. La lama bicorticale per la mandibola comeunica risoluzione in creste osse particolarmente riassorbite.21st GISI International Meeting on dental implant-tran-splant; Bologna, Italy. 1991.11. BIANCHI A., SANFILIPPO F., ZAFFE D. Implantologia eimplantoprotesi. Basi biologiche. Biomeccanica. Applicazionicliniche. Torino: UTET; 1999. p. 374-375.12. PASQUALINI M.E. Implantoprotesi in un caso di monoe-dentulismo: analisi retrospettiva a 27 anni. Dent Cadmos1999;10:61-64.13. LINKOW L., MANGINI F. Tecniche implantari ed im-plantoprotesiche. Padova: Ed. Piccin;1997.


121

122

123

Fig. 121 The mini-blade and its fixed abutment.Fig. 122 Placement.Fig. 123 Loading.

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14. PASQUALINI U. Ricerche isto-anatomo-patologiche inImplantologia. Associazione Italiana Impianti Alloplastici1972;5:40-7.15. CAMERA A., PASQUALINI U. Comportamento dell’epi-telio umano intorno ai perni uscenti degli impianti endossei.Associazione Italiana Impianti Alloplastici 1972;3:12-7.16. PASQUALINI M.E. Prostetic implants in monoedentu-lism: retrospective case analysis after 33 years. Magazjn Sto-matologiczny 2005 Lublin (Poland);12:56-9. 17. PASQUALINI U. Le patologie occlusali. Eziopatogenesi eterapia. Milano: Masson; 1993. p. 387-88.18. PASQUALINI U. Le patologie occlusali. Eziopatogenesi eterapia. Milano: Masson; 1993. p. 389-90.19. PASQUALINI M.E. Uso e possibilità delle mini lame. At-ti del I Seminario Intern di Clinica Implantologia ANIO; Ba-ri. 1982. Bari: Dedalo Litostampa; 1986.20. DAL CARLO L. Nuova tecnica per l’inserzione di impian-ti a lama: estensione distale endoossea. Dent Cadmos2001;16:41-9.21. DAL CARLO L. Investigation on the implant type more

proper to preserve the inter-proximal bone peaks. EuropeanJournal of Implant Prosthodontics 2007 Fall;2(3):89-97.22. TRISI P., QUARANTA M., EMANUELLI M., PIATTELLIA. A light microscopy, scanning electron microscopy, and la-ser scanning microscopy analysis of retrieved blade implantsafter 7 to 20 years of clinical function. A report of 3 cases. JPeriodontol 1993 May;64(5):374-8.23. LINKOW L., DONATH K., LEMONS J.E. Retrieval ana-lyses of a blade implant after 231 months of clinical function.Implant Dent 1992 Spring;1(1):37-43.

Figs. 96–116 Courtesy of Pierangelo Manenti.Figs. 8, 9, 18, 19, 22, 58, 60–63, 67, 68, 72, 75, 78, 82-84, 89–93from U. Pasqualini, “Le patologie occlusali. Eziopatogenesi e terapia.”Milan: Masson, 1993. Figs. 58, 60–63, 66, 68 from M.E. Pasqualini, “Implantoprotesi in uncaso di monoedentulismo. Analisi retrospettiva a 27 anni.” DentalCadmos 1999;10; 61–64.

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CHAPTER Xin collaboration with dr. Pierangelo Manenti

T he topic we are going to cover is of great rel-evance. It was observed for the first timewhen Pierangelo Manenti removed a titani-

um needle that was completely blocked inside thebone due to a bony ankylosis process. It was visual-ized histologically by Donath with his extraordinaryground section technique, which is ideal for obtainingwell-stained histological specimens including boneand metal in sections only a few microns thick (1).Before Donath, on various occasions others hadtried to obtain similar histological sections of peri-implant tissues, grinding them coarsely and pro-gressively with the included metal, in order to al-low the histologist the direct examination of theircontact areas.Carlo Zerosi of the University of Pavia commentedon these attempts as early as 1956 (2, 3).

The study of the behavior at the interface between al-loplastic structures and host tissues is not an easy task.The examination of their direct relationships with boththe metal structures and the surrounding tissues wouldbe highly desirable. Nevertheless, this hoped-for studyis prevented by the enormous technical difficulties in-volved in obtaining a section of the metal structure andhost tissues thin enough to allow examination withoutaltering their in vivo relationship: one could resort tousing ground sections, following inclusion in a sub-stance strong enough to hold the metal fragment dur-ing mechanical grinding of the section; alternatively,examination with reflected light could be used, accord-ing to the technique employed for the microscopicstudy of opaque objects. In our opinion, neithermethod permits clear differentiation or adequate stain-ing of the different structural elements. If anything,they might represent a complement to the traditionaltechnique whereby, following bone decalcification,metals are removed in order to analyze the appearanceof the contact surface without them.

In 1958 Zerosi presented a “mixed” histologicalspecimen (metal and surrounding tissue) (Figs. 1,2), obtained using the ground section technique.The technique devised by Zerosi now has purelyhistorical value, but his specimens allowed him topresent the concomitant histological image of a Vi-tallium inclusion and its surrounding tissues for the

OSSEOINTEGRATION OR “INTEGRATING BONY ANKYLOSIS”

Introduction

1

Fig. 1 Histological specimen prepared by Zerosiin 1958 using the ground section technique, showing that the

metal fragment of an experimental subperiosteal implantplaced in a dog is connected with the surrounding

connective sleeve. Fig. 2 This micrograph at highermagnification shows the strong adhesion between the

connective fibers and the metal surface (grind section technique, 1958).

2

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first time. Although they were quite thick, the sec-tions were nevertheless translucent and providedapproximate histological images, thus allowing Ze-rosi to diagnose that the tissue around the Vitalliumartifact exhibited acanthosis. In fact, to interpret thesections observed under the microscope beyondthe shadow of a doubt, they could be no thickerthan 10 microns, in order to allow the passage oflight and make the details visible. The reader cancompare the different patterns of the thick groundsections of 70-100 μ in Figures 1 and 2, and thehistological sections (also performed by Zerosi) ofspecimens where the metal inclusions were re-moved (Figs. 3, 4). Zerosi employed his personaltechnique, successfully removing the metal struc-tures of the implant without altering the specimenat the implant/integrating tissue interface (4). Nev-ertheless, Donath must be credited with making itpossible to obtain clear and precise ground sectionsof metal inclusions and their surrounding tissues,demonstrating that the presence of macroscopic re-tentions is not essential for osseointegration, as itoccurs through bony ankylosis that also takes placealong the smooth surfaces of buried fixtures (5, 6).

“Bony ankylosis”of emerging needles

Many colleagues who employed the tripod with thesmooth emerging needle technique (with no sur-face treatment) had the chance to observe that, incases of accidental fracture, the fractured needlewas sometimes impossible to remove from its bonesite. We are not referring to difficulties in removingthe needle with pliers, but to cases in which it wasimpossible to remove even with additional force ex-erted by repeated and violent percussion. Theseepisodes were reported as rare occurrences, and nobiomechanical explanation was offered as to the re-tention of artifacts as smooth as needles. These re-ports were not occasioned by the singularity of theextraordinary mechanical retention of the fracturedneedles, but by the opportunity to show how theresidual emerging ends could be re-exploited (Figs.5-13) using the intraoral solder. Through direct mi-croscopic vision, Donath’s ground sections had al-ready demonstrated that even with emerging vent-ed implants kept in a quiescent state during repar-ative osteogenesis, the newly formed bone apposedthe metal structures without the juxtaposition ofcollagen fibers, which was instead a constant find-ing with any kind of implant subject to externalstress during this rearrangement phase (7-14).

Fig. 3 Zerosi’s histological section and original illustrationof a subperiosteal implant on a dog after implantremoval (1958).Fig. 4 Another section and illustration (1958).

3

4

137

Employing Donath’s original technique combinedwith their own methods, Quaranta, Scarano and Pi-attelli confirmed these observations with analogousfindings at the interface area (15, 16). With anoth-er ground section technique1 Vito Terribile WielMarin, Piero Passi and Antonino Miotti (17)demonstrated analogous bone apposition on a Tra-monte screw that had been loaded for years beforefracturing.Supplementing the experiences of his few predeces-sors, Bianchi conducted a very detailed study onhow peri-implant bone adapts in terms of densityand architecture as a reaction to functional pros-thetic stress in vivo. According to Bianchi, the term“functional ankylosis” was more precise - and bet-ter reflected the results of his scanning microscopestudy - to describe the outcome between the bonetissue and the osseointegrated implant. He con-ducted one of the first studies analyzing the behav-ior of the integrating bone/metal interface of a hol-low cylindrical implant. His article was illustratedwith images at increasing magnification (SEM 19x,SEM 78x and SEM 200x), in which one can see thatthe bone in direct contact with the metal exhibitscharacteristic “interwoven fibers”, which can be

recognized by their uniform appearance and the ab-sence of mineralized matrix. He drew the same con-clusions even after analyzing a block section of adisk implant (SEM magnification 60x, 65x and250x), stating that “no evidence of osteoclastic ero-sion was observed” at the integrating bone/metal in-terface.In his third work, conducted using the samemethod to study the integrating bone/metal inter-face, Bianchi added that “between the peri-implantbone and the surface of the titanium screw therewas virtually always a gap of about 1 μ that, evenat the highest magnification (SEM 250x), did notshow the presence of fibrotic or other types of softnon-mineralized tissues”. Therefore, he speculatedthat this minimal gap was an artifact due to boththe preparation technique of the block section -which first required a complex dehydration proce-dure - and the subsequent sections, which mayhave been altered by the fact that metal and tissueshow different resistance to cutting (18).Nevertheless, while all of these studies incontrovert-ibly demonstrated that there was no apposition ofnon-mineralized tissue at the integrating bone/met-al interface, they did not posit that this kind of func-

Osseointegration or “integrating bony ankylosis” X

5 76 8

9 1110 12 13

1 Interesting method, but based on Donath’s original techniques.

Fig. 5 Very severe post-traumatic bone atrophy treated with 1.1-mm-diameter needles (1987). Fig. 6 Radiographic checkup uponcompletion (1987). The needle tips seems to penetrate the nasal cavity, but mastery of this placement technique permits correct bicorticalism

due to the bucco-palatal inclination of the implants, whose tips must reach the deep cortical bone.Fig. 7 Template for insertion of the needles shown in the previous image. Fig. 8 Fracture of one of the tripods after 3 years (1990).

Fig. 9 The flap opening reveals the exposed needle fragment, which is impossible to remove without a block section. Fig. 10 Fragmentretrieval and placement of new needles. Fig. 11 X-ray of the two new needles welded to the fragment.

Fig. 12 The new finished abutment. Fig. 13 Definitive crown (1990).

in any of the examined sections” (Fig. 15). Theslides were checked and photographed by Zerosi atincreasing magnification (from 15x to 250x). Hehad several considerations to make. “[T]here is nodoubt that the alveolar bone has closely adhered tothe metal without the juxtaposition of connectivefibers. . . . I fully agree that this relationship be-tween the bone and the implant should be consid-ered ankylosis, which has improperly been definedas osseointegration based on the widespread termpopular today. The sections are exceptional and Ibelieve that nothing else can be done to improvethem” (Fig. 16).Following further studies2, it was concluded thatthe lower magnifications (80-100x) do not permitgood concomitant focus of the round metal sectionsand the respective integrating tissue due to limita-tions that have to do with optical physics, but at ahigher magnification the remarkable absence of so-

138


tional ankylosis has a specific retentive functionlinked to its peculiar etiological mechanism, an as-pect that would call into question the alleged needto provide the implants with undercuts and/or re-tentive profiles. In 1999 we were able to present thisimportant confirmation for the first time (19).

The retention of smooth metal surfacesNobody had yet demonstrated why even smoothartifacts such as needles (Fig. 11) could be firmlyfixed within the new bone. The block section of theneedle exhibits the same histological pattern, withthe apposition, by ankylosis, of new bone thatstrongly adheres to the “smooth” surface of the nee-dle (Fig. 14).The aforementioned block section was sent to theInstitute of Oral Pathology at the University ofHamburg, headed by Donath, the inventor of thevery modern ground section technique. Donathperformed ten sections, all perpendicular with re-spect of the long axis of the needle, in order to vi-sualize the edge of the metal (or a portion of it),along with its integrating bone, for each specimen.The sections were stained with toluidine blue sinceit is the only stain that can penetrate the specimensin the special self-curing resin used to obtain thethin ground sections.Donath sent the slides back along with the follow-ing report. “Needle implant, 1.4 cm long, sur-rounded by 0.8 cm of bone tissue. The specimenwas cut into ten transverse sections stained withtoluidine blue. Histologically, the compact lamellarbone is in contact with the implant surface in eachsection. Single osteone channels are adjacent to thebone and the implant surface. Isolatedmacrophages are found on the bone surface afterthe implant is removed. The adjoining connectivetissue shows isolated lymphocytes. Histologicalfinding: needle implant in direct contact with thebone, without the juxtaposition of connective tissue

14Fig. 14 The block sectiongiven to Donath.

15

2 Study conducted at the Institute of Pathological Anatomy of San CarloBorromeo Hospital in Milan, in collaboration with the director, R.Schmidt and his assistant E. Schiaffino.

Fig. 15 Donath’s original report (1996).

Fig. 16 Original letter with Zerosi’s considerations (1996).

16

139

Osseointegration or “integrating bony ankylosis” X

17 18 19

20 21 22

23 24 25

26 27 28

29 30 31

Fig. 17 Histological section showing the metal of the sectioned needle (black), and the perfect bony ankylosis of the integrating bone in thesurrounding area (arrow). The clear areas represent medullar spaces. Even with a small implant surface the new bone

structure is very suitable for load bearing. Fig. 18 Another section at a higher magnification. Figs. 19-28 Progressive magnificationswith remarkable histological details. Fig. 29 This image shows perfect bony ankylosis, the circumferential architecture of the single

osteones, and the presence of osteocytes perfectly included within their niches (toluidine blue – 80x). Fig. 30 Interpenetration of the bonetissue along the seemingly smooth surface of the needle (toluidine blue – 100x). Fig. 31 Section at 250x showing the perfect

osseointegration, and the countless micro-undercuts of the metal.

lutions of continuity at the interface level is evident.This is demonstrated by the last image (250x) at thehighest magnification. Here we can clearly observethat the integrating ankylosis of the cancellous bone

occurred on a surface that is actually far from beingsmooth, as it has countless micro-undercuts.Readers can find additional details in the figure cap-tions (Figs. 17–31).

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ConclusionsThe study of the block section of the smooth nee-dle and surrounding tissue allows us to draw theseveral conclusions.1) It is not true that only buried implants can os-

seointegrate after months of passive housing be-low the mucosa.

2) Given their mechanical stabilization by meansof bicorticalized (or tricorticalized) compo-nents, partially buried and immediately loadedimplants also undergo successful osseointegra-tion, giving the patient the benefit of wearingtemporary and definitive prostheses almost im-mediately.

3) When properly placed in a tripod or bipod fash-ion, or as support for other types of implant,smooth metal needles can also counteract greatstress and traction, even when their bodies areset mainly within the cancellous bone above thecortical bone that houses the needle tip.

There is no need to expound further on the histo-logical patterns, as they are amply described in thefigure captions.

References

1. DONATH K., BREUNER G. A method for the study of un-decalcified bones and teeth with attached soft tissues. The Sä-ge-Schliff (sawing and grinding) technique. J Oral Pathol1982 Aug;11(4):318-26. 2. PEYRONE G., ZEROSI C., SEBASTIANI E. Impianto spe-rimentale su cane e controlli istologici. Rass Trimest Odonto-iatr 1956;4:101.3. ZEROSI C., BORGHESIO A., BARATIERI A. Impiantocompleto sperimentale su cane e controlli istologici. Rass Tri-mest Odontoiatr 1956;4:50.4. ZEROSI C. Dental histology: histological principles of mi-croscopic technics. Dent Cadmos 1985 Sep 30;53(14):17-64.5. DONATH K. Fundamentals of pathologic anatomy and pa-thophysiology for implantation success. Niedersachs Zahnar-ztebl 1991 Apr;26(4):203-5.6. DONATH K., ROMANOS G., TOH C.G., SIAR C.H.,SWAMINATHAN D., ONG 1. A.H., YAACOB H., NENTWIGG.H. Peri-implant bone reactions to immediately loaded im-plants. An experimental study in monkeys. J Periodont 2001Apr;72(4):506-11.

7. BIANCHI A., GALLINI G., FASSINA R., SANFILIPPO F.Analisi al SEM dell’interfaccia osso-titanio di un impianto alama. Il Dentista Moderno 1994a;7:1107-13.8. BIANCHI A., GALLINI G., FASSINA R., SANFILIPPO F.Analisi al SEM dell’interfaccia osso-impianto di una vite sot-toposta a carico funzionale immediato. Il Dentista Moderno1994f;9:1499-1503.9. BIANCHI A., MARTINI G., FASSINA R., SANFILIPPO F.Indagine al SEM su carico e organizzazione ossea perimplan-tare. Il Dentista Moderno 1995b;4:567-71.10. BIANCHI A. Block-section di un impianto a cilindro ca-vo. Osso perimplantare: analisi al SEM. Il Dentista Moderno1996a;4:491-96.11. BIANCHI A. Analisi comparativa a luce polarizzata e mi-croradiografia di osso perimplantare. Il Dentista Moderno1996b;5:669-76.12. BIANCHI A., FASSINA R., SANFILIPPO F. Block-sectiondi un impianto a vite. Il Dentista Moderno 1996a;3:357-62.13. BIANCHI A., GALLINI G., FASSINA R., SANFILIPPO F.,ZAFFE D. Morphostructural relationship between bone andimplant: comparative analysis by optical microscope and bymicroradiography. Int J Periodontics Restorative Dent1997b;6:3-11.14. DONATH K., NYBORG J. Esame istologico post mortemdi una mandibola con sei viti bicorticali. Odontostomatolo-gia ed Impiantoprotesi 1991;8:51.15. PIATTELLI A., SCARANO A., QUARANTA M. High-pre-cision, cost-effective cutting system for producing thin sec-tions of oral tissues containing dental implants. Biomaterials1997 Apr;18(7):577-79.16. PIATTELLI A., RUGGERI A., FRANCHI M., ROMASCON., TRISI P. An histologic and histomorphometric study ofbone reactions to unloaded and loaded non-submerged sin-gle implants in monkeys: a pilot study. J Oral Implantol1993;19(4):314-20.17. PASSI P., TERRIBILE WIEL MARIN V., MIOTTI A. Biolo-gic investigation on two titanium screw dental implants inhumans. Quintessence Int 1989 Jun;20(6):429-34.18. BIANCHI A., SANFILIPPO F., ZAFFE D. Implantologia eimplantoprotesi. Basi biologiche. Biomeccanica. Applicazionicliniche. Torino: UTET; 1999. p. 144-239.19. PASQUALINI U., MANENTI P., PASQUALINI M.E. Inda-gine istologica su ago emergente fratturato. ImplantologiaOrale 1999;2:17-22.

Figs. 1–4 Courtesy of Carlo Zerosi, University of Pavia.

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CHAPTER XIin collaboration with Franco Rossi and Domenico Colombo

On rare occasions Tramonte’s self-threadingscrew implants, like all cylindrical screwswith wide coils, can fail due to accidental

contact with lateral sections of compact bonealong the inserting tunnel. During the forced pro-gression of the screw and after slight impaction ofthe first thread against more compact bone,which cannot be penetrated further, this genera-tes two equally undesirable events: 1) deformation of the screw threads, leading to

compression, ischemia, and subsequent boneand implant expulsion by resorption;

2) deflection of the long axis (core) of the im-plant, whose torsion can cause screw fractureor change its direction toward softer cancel-lous bone, where the screw destroys the frag-ile bone trabeculae because of the ellipticalrather than circular progression of the implant(due to the deformation of the core), thus

jeopardizing the chance of primary stability1.These problems led to the invention of what havecome to be called “quick” screws, not just as analternative to the Tramonte screw implant, but asa first attempt to overcome these obstacles (1979)(1-9).The quick screws are titanium implants with thesame profile as Tramonte’s steel tappers with acentral tapered core, designed to be inserted intunnels with a wider diameter than those pre-pared for the original self-threading screws.Dubbed “quick” because they are placed withouta tapper, they have a sharp tip with a small outletchannel, and are designed to continue for a shortsegment past beyond the bottom of the prepara-tion site in order to add stability, where needed.The outlet channel does not add any pathologicalstress and prevents the very dangerous expulsiveconsequences of overscrewing, which acts like a

THE QUICK SCREWS

1 2 3

1 See Figs. 46–48 in Chapter 4, Part II, on the Tramonte screw.

Fig. 1 The quick screws designed by Pasqualini and the self-centering drill (center). Fig. 2 The principle of the corkscrew effect.Overscrewing and subsequent ischemia, necrosis, pain and expulsion. Fig. 3 The arrow points to the small outlet channel of the screw.

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corkscrew inside the bone (Figs. 1-3).The housing tunnels, which have a larger diam-eter (0.1-0.2 mm) than the cores of the quickscrews, are prepared with a series of four self-centering drills with a triangular section and pro-gressive diameter (1.1, 1.6, 2.1 and 2.6 mm).The drill tips have sharp cutting edges andbeveled flanks. Since the latter do not exert anycutting action, they cannot deform the tunnelwalls (Fig. 4).During preparation of the implant site, it is criti-cal to use all the self-centering drills with increas-ingly larger diameters. This fully exploits the dis-tinctive characteristics of the sharp triangular tip,avoiding the risk of bone overheating due to ex-cessive pressure or changes in the direction of the

4

Fig. 4 The self-centering drill and two screws differing in length.

5 76

8 9 10

1211 13 14

Fig. 5 The surgical bore made with a self-centering drill. Fig. 6 Correct placement of the screw and detail of its sharp tip, which addsstability upon contact with the cortical bone. Fig. 7 Traumatic loss of the upper incisors (1985).

Fig. 8 Flap detachment and view of the surgical field. The arrow points to an area with severe post-traumatic bone resorption.Fig. 9 A self-centering drill creates the first segment of the surgical groove. Fig. 10 Quick screw right after placement.

Fig. 11 Another screw placed in the avulsed lateral incisor area. Fig. 12 The self-centering drill in the contralateral incisor socket.Fig. 13 Implant placement. Fig. 14 The arrow points to the placement direction of the last screw.

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initial tunnel, which is made with the thinnestdrill (probe drill) after the first intraoral X-ray(Figs. 5-14).If the surgical tunnel does not meet the require-ments (note that the diameter of the first self-cen-tering drill is 1.1 mm), the tunnel trajectory caneasily be modified without any further damage tothe bone.The tip and the smooth flank of this drill, which

is quite different with respect to the helical typescommonly used in implant surgery, can be deci-sive - in a positive way - in the event of acciden-tal perforation of the mandibular canal and pos-sible contact with the inferior alveolar nerve.Nerve contact, which produces a sensation simi-lar to being pricked by a needle, can cause tem-porary paresthesia but not the permanent lesionscaused by the use of rotating spiral instruments.

The quick screws XI

15 1716

18 19

2524 26 27

21

20

22 23

Fig. 15 The screw in place. The self-centering drill is on the right. Fig. 16 The area with bone defect is filled with non-resorbablehydroxyapatite granules, which will prevent the flap from collapsing onto the area (1985). Fig. 17 The suture. Concomitant severe mobility

of the lower incisors (arrows). Fig. 18 Immediate provisionals at surgery completion (1985). Fig. 19 The patient’s smile.Fig. 20 Ten days after surgery. Fig. 21 Healing of the soft tissues at 40 days after surgery. Fig. 22 The 4 implant abutments and

the fractured gold-porcelain crown due to trauma (circle). Fig. 23 The prepared abutments before impression taking.

Fig. 24 Placement of the single gold-porcelain crowns. Fig. 25 The finished case (1985). Figs. 26, 27 Radiographic checkup.

The quick-screw implants, composed of fivethreads, are manufactured in three differentlengths (13, 16, and 21 mm up to the neck), cor-responding to the notches carved on the self-cen-tering drills (Figs. 15-23). They can be used as afirst-choice implant, but are particularly indicat-ed when, during placement of other types ofscrews, one encounters - or expects to encounter- an obstacle along the tunnel, represented bycortical bone that can deflect the screw trajectory(Figs. 24-38).

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The MUM mini-implants

Quick screws reduced the rate of failures (rare asthey may have been), but they did not complete-ly overcome the drawbacks described above Despite their tapered profile, they sometimes raninto problems similar to those observed withcylindrical screws when the wider coils hit theside wall of compact bone. Studies were conducted based on mechanicalprinciples, using screws with different profiles ac-

2928 30

37 38

31 33 34

35 36

32

Fig. 28 The final smile. Fig. 29 Appearance of the mucosae and the crowns (2007). Fig. 30 Detail. Note the gingival stippling.Fig. 31 The X-ray confirms the optimal stability of these implants and subsequent rehabilitations performed with other types on implants overthe course of 22 years. This was possible thanks to the methodical checks of centric and dynamic occlusion. Fig. 32 Radiographic detail of

the quick screws (April 18, 2007). Fig. 33 The histological behavior of these single-step screws is confirmed by the study of the blocksections reported in the book by Andrea Bianchi, Francesco Sanfilippo, and Davide Zaffe Implantologia e implantoprotesi. Basi biologiche.

Biomeccanica.Applicazioni cliniche. Fig. 34 Detail of the previous image at a higher magnification, showing the titanium threadflange that has been bent back. Even around the thread defect, the bone pattern looks uniform.

Fig. 35 The bone tissue surrounding this thread of a single-step screw has been perfectly adapted. Note the thin layer of lamellar boneabove a first layer of interwoven fibers in direct contact with the implant surface. Fig. 36 Cancellous bone compaction. The screw removed

after many years of service shows significantly denser bone tissue around it.Fig. 37 Close-up of the previous image after 12 years of prosthetic loading. Fig. 38 The same thread viewed under the SEM.

145

The quick screws XI

cording to the material into which they are insert-ed. Therefore, “wood” screws with wide coils areused for softer materials, whereas “iron” screws,with less prominent threads, are employed forvery hard materials. These observations made itpossible to design threaded implants with small-er coils, named MUM, an acronym devised fromthe initials of the first names of the professionalswho designed them in 1983 (Mimmo Colombo,Ugo Pasqualini and Marco Pasqualini). Patentedin the United States in 1987, they can also beused to screw in two-step abutments (Figs. 39,40).The real innovation of this type of implant is rep-resented by the thin thread, whereas preparationof the bone insertion tunnel is the same and isperformed using self-centering drills with a diam-eter larger than the implant cores. Consequently,the thinner and smaller threads of the MUM im-plants are always inserted into bone tunnels larg-er than their shank, and they penetrate the com-pact bone walls only marginally, without causingany deflection or secondary pathological com-pression.The diameters of the MUM implant cores are re-spectively 1.5-2.0 and 2.5 mm, whereas the out-er diameters - including threading - are respec-tively 2.1-2.6 and 3.1 mm. The diameters of theself-centering drills are respectively 1.1 (probedrill to assess the distance to the opposite corticalarea), 1.6, 2.1 and 2.6 mm.The initial unthreaded portion is directional,while the final part (neck), also unthreaded,adapts itself perfectly without any compression,even when placed between the closer walls ofvery thin ridges, from which the implant emerges,surrounded by adequate mucous tissue (Figs. 41,42). Implant screwing is always performed manuallyusing a special hand wrench. The implant coreadvances without compression against the tunnelwalls, which are 1/10 mm larger, while thethreaded portion carves the bone to a depth ofjust 0.25 mm. Tapping is advised only in the frontal area of veryatrophic and compact mandibles (Figs. 43-46).The MUM implant with core of 1.5 and 2.0 mmshould always be bicorticalized and, if necessary,joined with similar implants or deep balancingneedles by means of intraoral soldering. Thismakes them very strong, immediately stable, andable to withstand the immediate load of singleand multiple temporary prostheses. The MUM implants must be acknowledged as theforerunners of the now-numerous family of what

39 40

Fig. 39 The U.S. patent for the MUM mini-implants (1987).Fig. 40 Original drawing.

41 42

43 44

45 46

Fig. 43 The implant shapes used for the treatment of the followingcase. Fig. 44 Panoramic X-ray. Fig. 45 The flap opening

shows severe bone atrophy. Bone grafting procedures were not verycommon nor commonly advised at the time (1990).

Fig. 46 Placement of the first MUM mini-implant with a stabilizing needle.

Fig. 41 Demonstrative anatomical sections of the ideal site for MUMimplants: thin bone with close-set cortical walls.Fig. 42 Three MUM implants with different diameters (arrows) and thedrills used for their placement.

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have been termed mini-implants, as for all prac-tical purposes they are indeed “mini” (10-12). Unsurprisingly, as was the case with all the one-step implants, they were immediately criticizedby the mainstream science of the era, which cat-egorically recognized only the validity of two-stepimplants, which were passively buried andshielded from external stresses, deeming single-step implants to be obsolete and immediate load-ing unfeasible.Time has fully proved the unquestionable validi-ty of immediate loading, which has now beenunanimously recognized by the international sci-entific community (13-16). This favored the ad-vent of several mini-implants proposed by a num-ber of manufacturers. This is a source of immensesatisfaction and it legitimizes the innovativenessof the MUM implants (Figs. 47-55).The quick screws in the upper maxilla and mini-implants in the front area of the mandible be-tween the mental foramens can also be employedas first-choice implants for immediate loading(17) (Figs. 56-60). This technique guarantees ahigh success rate, but must be employed by fol-lowing a strict operative surgical protocol that canbe divided into four steps.

Step 1. Number of implantsIn a single session, it is advisable to place as manyimplants as possible, corresponding to the num-ber of the missing teeth (18, 19).

Step 2. Primary stabilizationAll implants must reach and penetrate the deepcortical bone in order to achieve the bicorticaliza-tion that determines primary stability (20, 21).

47 48 49

50

Fig. 47 The surgical technique employed in this case of edentulism: a MUM implant with a diameter 2.1 mm and a stabilizing needlewith a diameter of 1.3 mm. Fig. 48 After completion of surgery.

Fig. 49 Radiographic checkup and the reinforced provisional (palatal view), cemented right after surgery. Note the bicorticalism,deep balancing with stabilizing needles, and intraoral weldings.

51

52

Fig. 50 Provisional in centric relation occlusion at suture removal (10 days).

Fig. 51 Definitive gold-porcelain prosthesis made with two bridges joined by an inlay, due to the need to compensate for implant inclination, which did not

permit the insertion of a single bridge.Fig. 52 The finished case (1990).

on the mucosa without any compression andwelded to each implant with the intraoral solder.The supporting bar must be placed so that theemerging pre-prosthetic abutments of the im-plants are free in the oral cavity (3, 22-26).

147

Step 3. Immediate splinting Extremely strong and stable splinting of the im-plants can be obtained using a titanium support-ing bar with diameter of 1.2 mm that is placedpalato-lingually with respect to the implants, set

The quick screws XI

56

Fig. 56 Self-centering drill (left) and MUM implant (right).Fig. 57 Edentulous site ideal for the placement of a MUMimplant.Fig. 58 Correct placement in very compact bone.Fig. 59 The third MUM implant placed and a follow-up X-ray.The included premolar (arrow) is asymptomatic.Fig. 60 The three single crowns on implants.59

60

57 58

Fig. 53 Lower edentulism was solved with a blade connected to the existing prosthesisFig. 54 The patient’s smile (1990).

Fig. 55 The orthopantomography shows marked horizontal atrophy in localized sectors, due to the functional loads on an extremelyreduced bone substrate. The patient has been wearing the same prosthesis for 18 years (2008).

53 54 55

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Step 4. Temporary prosthesisDuring the same session a temporary resin pros-thesis is applied immediately: it must have correctheight and be occlusally balanced, without inter-fering with the static and dynamic equilibrium(27).The ideal screws for the upper maxilla are thosewith wide threads, as they can provide greaterstability when inserted into bone that is not par-ticularly compact. The ideal screws for the central mandible area in-stead have narrower threads that can better pen-etrate this highly mineralized bone without com-pressing it. Their shape resembles the iron screwsemployed for very compact materials. The MUM implants, and Garbaccio’s screws offerthese features.

“Deep balancing” of the implant

In terms of resistance to static and dynamic oc-clusal stress, the one-step implants can also ex-ploit the supporting structures that, joined to-gether, are able to distribute stress across a broad-er surface.A natural example can be found in the morphol-ogy of molar roots, which are designed to bearmost of the static stress of mastication and deg-lutition. In addition to being in a region of com-pact bone, these teeth also distribute the loadacross areas that are broader than their occlusalsurface2.

2 See Chapter 6, Part I, on centric occlusion contacts of U. Pasqualini, Le patologie occlusali. Eziopatogenesi e terapia. Milan: Masson, 1993, pp.43–56.

Deep balancing of the implant is achieved by in-fixing a needle that diverges with respect to theaxis of the main implant, which must reach andpenetrate the cortical bone deeply and be sol-dered to the screw at the point where it emergesfrom the bone (Fig. 61).Titanium needles (Scialom) with diameters of 1.1,1.2, and 1.3 mm are used as the supporting struc-tures of screw implants, quick screws and espe-cially the MUM mini-implants. They must beplaced so that they diverge with respect to thescrew and must be pushed deeply until theytouch and penetrate the cortical bone. They mustthen be soldered to the screw at the point wherethey emerge from the bone, using Mondani’s in-traoral solder: this is the only way that they canexert their stabilizing effect. In addition to increasing resistance to static anddynamic stress, deep balancing also exerts acounterclockwise action and provides great im-mediate primary stability due to the cortical sup-port. This prevents dangerous micromovements ofmore than 150 microns, as they are particularlyharmful and can potentially inhibit osseointegra-tion of the implants (28, 29).Deep balancing is particularly useful for all sin-gle-tooth implants (including post-extractiveones and those placed in poorly mineralizedbone) that will be loaded immediately. For exam-ple, we can cite post-extractive implants placed inshallow sockets, in which it is virtually impossi-ble to achieve immediate primary stability. Thus,they cannot be loaded immediately without deepbalancing.Even when dealing with particularly thin ridges,when augment surgery is impossible or undesir-able, MUM mini-implants (with a smaller diame-ter of 2.1 and 2.6 mm) are feasible. These implants are particularly effective becausethey are placed between the two close corticalwalls (buccal and palatal or lingual) and, as arule, they are supported by the deep corticalbone. This represents the ideal bone for implantswith very small core diameters, which can with-stand static and dynamic masticatory stress foryears without undergoing stress fractures (30-32), as long as an adequate number is insertedand protocol is followed. In all of these cases, deep balancing - stabilizationby means of needles - ensures increased resist-

61

Fig. 61 Deep balancing of a screw with a diverging needlereplacing an upper premolar.

ance that can withstand the test of time. The front sector of the mandible is composed ofvery compact bone. The screws placed into thistype of bone may sometimes be expelled due tonecrosis, as the tissue is overly compressed by thescrewing action and suffers reduced venous andlymphatic flow. In these cases, it is advisable toprepare osteotomies larger than the implant coresin order to avoid compression. Deep balancing of screws inserted in tunnelswider than their core (to avoid ischemia of thewalls) ensures the implant stability required toachieve osseointegration even with immediateloading3. This assures:

❚ an antirotational function;

❚ immediate loading;

❚ primary stability;

❚ greater resistance to static and dynamic stress.

The screw exploits deep balancing when it is usedas a double substitute implant for multi-rootedteeth. Deep balancing can be obtained by solder-ing one or two diverging needles to the abutment,or by joining the abutments of two adjacentscrews to form a single block.The figures exhaustively illustrate the surgicaltechnique as well as the long-term outcomes ofthis implant method, which is specifically de-signed for immediate loading.

First exampleRehabilitation with immediately loaded implantsin the completely edentulous upper maxilla of a46-year-old male patient (Fig. 62).Bone loss in the front area is evident in bothheight and width (Fig. 63). Implants were insert-ed according to the protocol (Fig. 64), with im-mediate placement of a temporary resin prosthe-sis that had the correct vertical height and wasocclusally balanced (Fig. 65).Due to the minimal bone thickness, implantswith a smaller diameter were placed (MUM mini-implants) in the front sector; the thread diameterranged from 2.1 to 2.6 mm.A bicorticalized needle was inserted besides themini-implants for reinforcing purposes. It wasplaced in the bone with a slightly divergent axiswith respect to the main implant, but parallel tothe abutment emerging into the oral cavity (forprosthetic needs); it was then welded with Mon-

dani’s intraoral solder, thus achieving deep bal-ancing.In addition, two implants placed in the right and

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The quick screws XI

62

63

64

65

3 See Figs. 21 and 22 in Chapter 9, and Figs. 1–24 in Chapter 13.

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68

69 70

66 67

left maxillary tubers, respectively, made it possi-ble to bypass the large maxillary sinuses (Fig.66).The exceptional stability of the implant permittedgood healing of the soft tissues (Fig. 67); the de-finitive gold-ceramic prosthesis was placed afterthree months (Fig. 68).The panoramic X-ray (dated 1993) demonstratesthe good status of the bone tissue, with no signs ofresorption cones around the implants (Fig. 69).Figure 70 shows the palatal image of the support-ing bar. The prosthetic crowns rest on the barwithout covering it. These conditions clearly fa-cilitate correct oral hygiene.The picture taken at the eleven-year follow-up al-so shows two new crowns on the lower canines(arrows) (Fig. 71). The OPG X-ray, also taken 11years later, confirms healthy bone conditionswith no signs of lesions (Figs. 72, 73).Scrupulous periodic checks of the occlusion (us-ing both very thin articulating paper and “Red In-dicator” dry self-molding varnish) and of oral hy-giene conditions are imperative in such cases.

71

72 73

Fig. 72 Ortho-panoramic of thefinished case (1996).Fig. 73 X-ray 11years later (2007). Notethe gold-porcelaincrowns on the lowercanines.

74

75

Fig. 74 Female subject, age 67, with a total upper prosthesiswith residual roots in an expulsive phase (2000).Fig. 75 Panoramic X-ray.

Second example (Figs. 74-85).

79

151

The quick screws XI

76 77

Fig. 76 The number of implants placed in a single session should correspond as closely as possible to the numberof missing teeth. In this case 14 fixtures were placed: 4 post-extraction implants, and 10 implants with the flapless

mini-invasive technique (Step 1 of the protocol). All implants must reach and penetrate the deep cortical bone to achieve thebicorticalization that determines primary stability (Step 2 of the protocol). Fig. 77 Immediate splinting is performed

with a titanium supporting bar with a diameter of 1.2 mm, set on the mucosa without any compression and welded to each implant by means of the intraoral solder (Step 3 of the protocol). The supporting bar must be placed so

that the emerging pre-prosthetic abutments of the implants is free in the oral cavity.

78

8180

Fig. 80 Correct positioning of the supporting bar and abutments before cementation of the definitive prosthesis.Fig. 81 X-ray of the finished case. Reparative osteogenesis is complete (90 days). These data are particularly interesting

because they demonstrate that immediate loading on very stable implants (as per protocol) not only fails to cause bone resorption, but also allows bone regeneration even in the extraction areas.

Note the spaces between the crowns.

Fig. 78 A resin provisional restoration is immediately applied during the same session.It has a correct height and is occlusally balanced, without interfering with static

and dynamic equilibrium (Step 4 of the protocol).Fig. 79 The panoramic X-ray shows incomplete healing of the post-extraction sockets (5 weeks).

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8584

Fig. 84 Follow-up at 7 years. Note the attractive appearance of the mucosae (2007).Fig. 85 The OPT taken 7 years later (2007) shows the good condition of the bone around all of the implants. The mandible was

rehabilitated in 2002 with a fixed prosthesis on implants, selected according to the different bone sites.

86

89

87

88

Fig. 86 Severe damage of the upper arch teeth of a patient with occlusal trauma. Note the single-tooth crossbite relation of thecanine, on the right side (1995). Fig. 87 Panoramic X-ray. Fig. 88 The 9 implants placed in a single session. The distal

implants on both sides are constituted by two soldered screws, to replace the multi-rooted teeth.Fig. 89 The temporary resin prosthesis, which was loaded immediately.

82 83

Fig. 82 Correct positioning of the abutments and the spaces between them makes it possible to place a definitive gold-porcelainprosthesis that respects oral physiology, without compressing the soft tissues (2000). Fig. 83 As shown, good oral hygiene can

be maintained even when there is a titanium supporting bar.

Third example (Figs. 86-93).

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Fourth example (Figs. 94-109).

The quick screws XI

90

93

91

92

Fig. 90 Occlusal checkup withthe Pasqualini stopper followingdefinitive gold-porcelain prosthesiscementation. The 2.4 shows apremature contact that must beeliminated.Fig. 91 Cemented definitiveprosthesis in occlusal balance.Fig. 92 Orthopanoramic of thefinished case (1995).Fig. 93 Detail of the doublesubstitute implants for the multi-rooted teeth.

98

101

99

100

96

97

94 95

Figs. 94, 95 Severely compromised mouth of a 42-year-old man, where the upper canines have migrated to the sites of the lateralincisors, due to agenesis. Fig. 96 The OPT X-ray shows the serious prosthetic mistake that was made by using two extension bridges to

replace the canines. These prostheses, now mobile, do not allow the lateral disclusion. Fig. 97 Placement of two single immediate loadingimplants on the canines (1993). Fig. 98 Healing of the soft tissues guided by the provisional crowns.

Fig. 99 The OPT X-ray shows the canine implants. They consist of a pair of bicorticalized MUM screws that were welded together.The X-ray shows other paired screws in the upper and lower molar regions.

Figs. 100-102 The implant’s emerging abutment before placement of the definitive prosthesis.

102

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103 104 105

108

106 107

Figs. 103-105 The singlegold-ceramic crowns replacing1.3 and 2.3 are cemented. Notethe good and healthy appearanceof the peri-implant gingiva.Lateral disclusion is correctlyprovided only by the canines.Fig. 106 The finished case(1993).Figs. 107,108 Pictures ofthe prostheses at a checkup in2007.Fig. 109 After 14 years thebone tissue is still intact aroundall the implants, with no sign ofresorption (2007).

Fig. 110 A 67-year-old completely edentulous male patient. Insertion of 12 one-step bicorticalized screw implants in the upper maxilla: 7Pasqualini screws and 5 Tramonte screws, splinted by means of soldered bar and immediately loaded with a temporary prosthesis (1996). In

the mandible were placed 12 two-step vented cylinder implants. Fig. 111 Close-up of the placement of the one-step screws in theupper maxilla. Fig. 112 The two-step implants placed in the mandible.

4 The photographs of this case are from Implantologia e implantoprotesi. Basi biologiche. Biomeccanica. Applicazioni cliniche by Andrea Bianchi,Francesco Sanfilippo and Davide Zaffe. The book, published by UTET in 1999, is a very representative and exhaustive study of the behavior of bonetissue surrounding all types of implants, both two-step and one-step.

112

109

110 111110

Fifth example4 (Figs. 110-122).

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The quick screws XI

115113 114

Conclusions

All colleagues who employ the intraoral solder ap-ply deep balancing to screw implants in cases sim-ilar to those presented here and in many other clin-

ical situations. This even makes it feasible to treatcases that would be impossible to solve with anyother technique.The definitive prosthesis can be placed in furcationareas, with optimal and enduring aesthetic results.

Fig. 113 Orthopanoramic of all the inserted implants (1996). Fig. 114 Healing of the soft tissues around the one-step screws splintedwith a titanium bar. Fig. 115 Upon completion of osseointegration, the splinting bar can be removed, and the implant abutments preparedand parallelized with a carbide bur mounted on a turbine handpiece. Fig. 116 The two definitive gold-porcelain prostheses immediately

after placement (1996). Fig. 117 Orthopanoramic of the finished case (1996). Fig. 118 The same case 11 years later (2007).

116 118117

119

121 122

120

Fig. 119 Detail of the goodcondition of the soft tissues after somany years, demonstrating theoptimal status of the underlyingbone.Fig. 120 The OPG confirms thestability of both the two-stepimplants and the screws, with nobone resorption. This demonstratesthat the prosthetic functional-physiological loading is successfulregardless of the type of implantemployed (2007).Figs. 121, 122The maintenance of long-termstability determined the specificand optimal peri-implantmorphostructural boneorganization, which can withstandhigh-intensity stress (2007).

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This contradicts the mistaken conviction that in im-plantology bi- and/or trifurcations are harmful forthe periodontium (see the cases described here) (8,83). Deep balancing immediately stabilizes the implantsby means of strong mechanical osseointegrationthat allows immediate cementation of the tempo-rary prosthesis, also favoring enduring biologicalosseointegration, with all the benefits that ensue.

Remarks

There is a risk that screws placed in the compactbone of the frontal section of the mandible can beexpelled due to tissue necrosis, since the tissuemight be overly compressed by the screwing andsuffer reduced venous and lymphatic flow. Thedeep balancing of screws placed in tunnels widerthan their core does not cause ischemia of the bonewalls and increases the chances of bone regenera-tion inside the “voids” thanks to the immobilizationand stabilization provided by deep balancing.

References

1. PASQUALINI U. Le patologie occlusali. Eziopatogenesi eterapia. Milano: Masson; 1993. p. 3-23, 176, 186, 338, 414.2. PASQUALINI M.E. Il carico immediato in implantoprote-si. Tecniche chirurgiche, risultati clinico-funzionali ed esteti-ci con protesizzazione immediata e definitiva precoce. Pro-ceedings of the Meeting of Implantology: Post-extraction im-plants. Past, present, and future; Chieti, Italy. 2002. p. 91.3. ROSSI F., PASQUALINI M.E., MANGINI E., MANENTI P.Carico immediato di impianti monofasici nel mascellare su-periore. Dent Cadmos 2005;73(5):65-9. 4. HRUSKA A., CHIAROMONTE BORDINARO A., MARZA-DURI E. Carico immediato post-estrattivo. Valutazione clini-ca su 1373 impianti. Dent Cadmos 2003;71(5):103-18.5. BIANCHI A., SANFILIPPO F., ZAFFE D. Implantologia eimplantoprotesi. Basi biologiche. Biomeccanica. Applicazionicliniche. Torino: UTET; 1999. p. 111-65.6. PIERAZZINI A., FANALI S., FANFANI F. Insuccessi in im-plantologia. Torino: UTET; 2001. p.184-200.7. PASQUALINI M.E. Il carico immediato in implantoprote-si. Tecniche chirurgiche, risultati clinico-funzionali ed esteti-ci con protesizzazione immediata e definitiva precoce. Pro-ceedings of the 5th International AISI Congress (Italian Aca-demy of Implant Stomatology); Verona, Italy. 2003. p. 97-8.8. BERTELé G., PASQUALINI M.E., BILUCAGLIA L., MI-RANDOLA A. Implantologia: dall’ipotesi al carico immedia-to. European Journal of Implant Prosthodontics 2005 May-Aug;2(1):65-87.9. BUCCI SABATTINI V. Tecniche ricostruttive e rigenerative

dei mascellari atrofici. I biomateriali: scelta, indicazioni e me-todi di uso. Torino: TU.E.OR.; 2007. p. 16-19, 287, 288.10. SENDAX V.I. Mini-implants as adjuncts for transitionalprostheses. Dent Implantol Update 1996 Feb;7(2):12-5.11. SALINA S., MAIORANA C., IEZZI G., COLOMBO A.,FONTANA F., PIATTELLI A. Histological evaluation, in rab-bit tibiae, of osseointegration of mini-implants in sites prepa-red with Er:YAG laser versus sites prepared with traditionalburs. J Long Term Eff Med Implants 2006;16(2):145-56. 12. GLAUSER R., SCHÜPBACH P., GOTTLOW J., HÄM-MERLE C.H. Periimplant soft tissue barrier at experimentalone-piece mini-implants with different surface topography inhumans: A light-microscopic overview and histometric ana-lysis. Clin Implant Dent Relat Res 2005;7 Suppl 1:S44-51.13. AVILA G., GALINDO P., RIOS H., WANG H.L. Immedia-te implant loading: current status from available literature.Implant Dent 2007 Sep;16(3):235-45.14. MISCH C.E., WANG H.L., MISCH C.M., SHARAWY M.,LEMONS J., JUDY K.W. Rationale for the application of im-mediate load in implant dentistry: part II. Implant Dent 2004Dec;13(4):310-21.15. MISCH C.E., WANG H.L. Immediate occlusal loading forfixed prostheses in implant dentistry. Dent Today 2003Aug;22(8):50-6. 16. BERTELÉ G., BUCCI SABATTINI V., BRUSOTTI C., DALCARLO L., FANALI S., FLORIS P.L., HRUSKA A.R.,LINKOWL., MANZANARES N.,PASQUALINI M.E., PIERAZZINI A.,PIZZAMIGLIO E., STOWELL J.W., TRAMONTE S.U. Con-sensus AISI (Accademia Italiana di Stomatologia Implanto-protesica) sul carico degli impianti. Dent Cadmos 2004:2;81-3.17. DIOTALLEVI P., MOGLIONI E., PEZZUTI E., PIERAZZI-NI A., PASQUALINI M.E., FLORIS P.L. Correlazioni biomec-canico-radiologiche nel riassorbimento osseo perimplantare.Studio comparativo su 47 soggetti. Doctor Os 2007Feb;18(2):117-123.18. MURATORI G. Implant isotopy (II). J Oral Implantol1995;21(1):46-51.19. MURATORI G. Isotopia e multicorticalità, due principifondamentali. Dent Cadmos 1991;59(8):15-47.20. GARBACCIO D. The Garbaccio bicortical self-threadingscrew. Riv Odontostomatol Implantoprotesi 1983 Jan-Feb;(1):53-6. 21. GARBACCIO D. Endosseous self-threading screws: bio-mechanical principles, surgical technic and clinical results.Dent Cadmos 1981 Jun;49(6):19-31.22. LORENZON G., BIGNARDI C., ZANETTI E.M., PERTU-SIO R. Analisi biomeccanica dei sistemi implantari. DentCadmos 2003;71(10):63-86.23. DAL CARLO L. Tecnica di protesi fissa su barra saldatanelle contenzioni definitive. Doctor Os 2004 Giu;15(6):637-45.24. HRUSKA A.R. Welding implants in the mouth. J Oral Im-plantol 1989;15(3):198-203. 25. VANNINI F., NARDONE M. Emerging transmucosal sin-

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gle-stage implants with electro-welding and immediate loa-ding. Annali di Stomatologia (est) 2004 Jul-Sept;3(LIII):129-35.26. APOLLONI M. Atlante pratico di implantologia dentale.Milano: Ed. Ermes; 1989. p. 124-31.27. PASQUALINI U. Le patologie occlusali. Eziopatogenesi eterapia. Milano: Masson; 1993. p. 385-414.28.BISCHOF M., NEDIR R., SZMUKLER-MONCLER S.,BERNARD J.P., SAMSON J. Implant stability measurement ofdelayed and immediately loaded implants during healing.Clin Oral Implants Res 2004 Oct;15(5):529-39.29. SZMUKLER-MONCLER S., SALAMA H., REINGE-WIRTZ Y., DEBRUILLE J.H. Timing of loading and effect ofmicromotion on bone-dental implant interface: review of ex-perimental literature. J Biomed Mater Res 1998 Sum-mer;43(2):192-203.30. PASQUALINI M.E. Le fratture da fatica dei metalli da im-pianto. Il Dentista Moderno 1993;11(2):31.

31. LORENZON G., BIGNARDI C., FANALI S. Insuccessiimplantari da frattura. Il ruolo della fatica dei materiali. Eu-ropean Journal of Implant Prosthodontics 2007 Spring;3(1):7-17.32. PIERAZZINI A., FANALI S., FANFANI F. Insuccessi inimplantologia. Torino: UTET; 2001. p. 93-160.33. PASQUALINI U. Le patologie occlusali. Eziopatogenesi eterapia. Milano: Masson; 1993. p. 391, 392.

Figs. 44–73, 84–109 Courtesy of Franco Rossi.Figs. 74–83 are from F. Rossi, M.E. Pasqualini, E. Mangini and P. Ma-nenti. “Carico immediato di impianti monofasici nel mascellare supe-riore.” Dent Cadmos 2005;73:565.Figs. 33–38, 110–112, 114–117 courtesy of A. Bianchi, F. Sanfilippoand D. Zaffe, from Implantologia e implantoprotesi. Basi biologiche.Biomeccanica. Applicazioni cliniche. Turin: UTET, 1999, p. 326–31.Figs. 113, 118–122 Courtesy of A. Bianchi and F. Sanfilippo.

The quick screws XI

TREATISE OF IMPLANT DENTISTRY CHAPTER XIIin collaboration with dr. Luca dal Carlo

T he concept of screw bicorticalism, introdu-ced by Dino Garbaccio in the early 1970s,represents another step forward in the evo-

lution of implantology. The need to reach the corti-cal wall opposite the needle insertion site had alrea-dy been suggested by Scialom (1-6), but no one hadever applied this principle to other types of im-plants.Garbaccio must also be credited with other con-cepts, including:1) the use of Torpan drills to prepare the tunnel

(Fig. 1), as they:a) do not overheat the bone since they act likethe blades of a rotating scalpel1;b) allow the oral surgeon to perceive the differ-ent resistance between compact and cancellousbone, making it possible to stop the drilling andthen the progression of the screw precisely at thecompact wall surface of the deep cortical bone;

2) screws composed of an initial smooth pointedsegment referred to as a nosepiece (Fig. 2),

which acts as a guide.The threads, which vary in number, start under thesmooth segment and have progressive diameters.The helical blade forming the threads has longitu-dinal notches that, by creating two cuts for eachthread, penetrate the tissue while simultaneouslyremoving bone fragments (Fig. 3).After the threads, the screw continues with asmooth flank with a diameter of 2.25 mm, endingwith a quadrangular portion used to connect the in-

THE GARBACCIO BICORTICAL SCREWS

1

2

3

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1 The comparison was made by Garbaccio himself.

Fig. 3 Close-up of the sharp thread.

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strument employed for manual placement2 (Figs. 4,5). With his consent, we have quoted passages fromGarbaccio’s first publication on the self-tapping bi-cortical screw. The article, which uses less technicalterminology than what is employed today, is never-theless clear, direct and didactic.

I am presenting this screw after years of testing, con-vinced of its validity. The design is based on two principles:1) bicortical stabilization,2) protection of the healing processes.

Bicortical stabilization

From a biomechanical point of view the permanent sta-bilization of the endosseous artefacts should benefitfrom the compact support structure situated on the ex-ternal surface of human bones. The mandible and themaxilla are no exception. The central spongy bone tis-sue has less retention and stabilizing capabilities and itis formed by few trabeculae, poorly mineralized, im-mersed in abundant medullar spaces. In 1972 Pasqualini had already proven that the major-ity of the implant failures “of unknown aetiology”where surgical error serious general illnesses and oc-clusal imbalance had been excluded, were due to thepoor retention capability of the medullar tissue, both

during the delicate reparative osteogenesis period, andthe following loading phase (7, 8). For these reasons I designed a screw that, due to its pe-culiar morphology, constantly exploits the principle ofthe bicortical support, taking advantage both of the re-sistance of the compact superficial occlusal layer andthe resistance of the opposite compact layer: the sinusplate or the compact plate of the palatine bone in theupper jaw, or the compact shell of the lower jaw beforethe mental foramen (9, 10).The bicortical support obtained as such is not acciden-tal as sometimes occurs during placement of some im-plants, but deliberate and constant.One limitation is represented by the distal mandibularareas, where reaching the lower cortical will entail therisk of lesions of the mandibular canal. . . . The system-atic exploitation of bicorticalism allows the rational useof the maximum biomechanical stability, with virtuallyno occurrence of failure.The screw I am presenting has a particular shape,which will be described in the next paragraph devotedto the protection of the healing processes.I must point out that this shape was also designed topermit rapid achievement of bicorticalism without thesurgical risk of incorrect placement.The self-tapping bicortical screw does not require theuse of tappers, and it is directly and permanentlyplaced inside the bone tissue following preparation ofa small tunnel made with a single drill (Torpan Maille-fer, diameters 1.2 mm and 1.3 mm). With this drill theoperator can perceive the different consistency of thevarious bone layers. After the resistance encountered inthe compact occlusal layer, the drill easily penetratesthe underlying cancellous layer (which practically pos-es no resistance) giving the operator the sensation ofadvancing in an “empty” space. When the drill tipmeets the distal cortical bone, the operator immediate-ly feels its resistance and must stop advancing the drill. At this point, the drill (or the hand graduated drill) ex-tracted full of blood will give a perfect evaluation of thedepth reached which will be compared to the screwshaft, where a reference notch will be made3,4. . . . Thescrew is then placed in the tunnel created by the drill,with no need for further drills with progressive diame-ters or tappers . . . .Another visual check, in addition to tactile sensitivity,is given by the notch made previously on the drill shaft,which should be at the external mucosal surface level

The Garbaccio bicortical screws XII

4 5

2 For a description of the surgical placement of the Garbaccio screw, with the detailed steps and instruments, see the website:www.garbaccio.it.

3 By making a small notch with a bur or marking it on the shaft (which must be dry) using a wax pencil.4 Garbaccio makes a reference notch on the smooth portion of the screw using a bur mounted on a high-speed handpiece, but an indelible marker can

also be used (being sure to dry the area first).

Fig. 4 Garbaccio’s principle of bicorticalism.Fig. 5 The Garbaccio screws.

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when resistance is felt. The bicorticalism, which blocksthe screw between the two compact cortical walls onboth sides, favors definitive consolidation by means ofreparative osteogenesis, thus protecting the “quiescentstate” already indicated by Pasqualini5 as indispensablefor good reparative osteogenesis of the surgical groovesmade for implant placement.

The author describes the other features of the bicor-tical self-threading screws that contribute to in-creasing initial stability:1) minimal tissue trauma, due to the small and thin

smooth apical portion, which guides the threadsalong the primary tunnel created by the drill ac-curately, avoiding friction, fractures and the cre-ation of false routes;

2) the shape of the threads with progressive diam-eters, each of which broken up by two sharpnotches, which penetrate the bone tissue with-out compression, thus creating an incisionwound in place of a lacerated and contusedwound, unlike other types of screws.

Healing is fast, with few painful side effects, and noareas of bone resorption. According to Garbaccio,the two notches carved on each thread ensure thatthe screw will be blocked and cannot be removedafter healing.Elimination of the tappers, permitted by the uniquescrew morphology, ensures exact positioning of thescrew even when the threads are temporarily exter-nalized as they go through a superficial area of verythin bone, given that further progression of thescrew will house them properly in a wider anddeeper bone area. The operating technique is worthdiscussing.During closed surgery6, which is the author’s pre-ferred approach, Garbaccio performs superficialanesthesia with a few drops of anesthetic injectedwith the Peripress syringe, invented by AmericoColombo of Como (11-14), into the submucosalperiosteum below the drill insertion site. This pro-cedure, which nevertheless produces immediateanesthesia that will last throughout the operation,helps reduced surgical trauma (15).Before placement of the bicortical screw the authoradvises checking the width of the first portion ofthe tunnel - widened by oscillating the drill in or-der to house the last portion of the screw shaft - us-ing an instrument that he named “tunnel check.” Its

diameter is slightly bigger than that of the end ofthe screw shaft, in order to avoid the risk of harm-ful compression of the bone walls by the rotatingpressure required to deepen the implant, followinga manual check of a sufficient “safety margin” of thetunnel.Recently he also added a manual instrument to histoolkit (the “hand graduated drill,” which reducesthe risk of error as it turns counterclockwise) in or-der to adjust tunnel roundness after drill oscilla-tion. The toolkit also features a series of hand drills, andan excellent cardan joint key, which makes it possi-ble to screw the bicortical implants in a distolingualdirection (16-26).

The histological behaviorof the tissues integrating the Garbaccio screws

The histological examinations of the behavior ofthe tissues integrating the bicortical screws, per-formed by O. Sarnachiaro, O. Bonal, E. GratoBur, and A. Vaamonde at the Histology Depart-ment of the Dental College, and the Primates Re-search Institute (both of which are part of theUniversity of Buenos Aires), confirmed that, fol-lowing screw removal, the bioptic specimensdemonstrated several aspects.1) The soft tissue sections harvested at the screw

neck had a physiological pocket of approxi-mately 1.5 mm, similar to those found aroundthe neck of healthy human teeth.

2) The deeper sections exhibit a “constant her-metical continuity mirroring the shape of thescrew and its osseointegration7”.

3) The perfect apposition of healthy newlyformed bone, both compact and cancellous,can be observed around all the metal struc-tures of each screw, without the interpositionof collagen fibers.

The authors added a series of specimens at 400xcollected around the unthreaded segment of theshaft, around the threads and at the short smoothapical portion. These additional specimens alsodemonstrate the perfect osseointegration that in-

5 See Chapter 8, p. 115.6 We mentioned our reservations in Chapter 4, Part II, although we are well aware that flapless surgery prevents pain and swelling, and promotes very

fast healing of the transfixed tissues.7 From the publication of Sarnachiaro, Bonal, Grato Bur and Vaamonde.

The specimen was fixed in formaline (Fig. 10)and sent to Karl Donath at the Department ofOral Pathology of the Eppendorf University Hos-pital of Hamburg; Donath is famed for devisingthe revolutionary histological technique that al-lows the concomitant sectioning of the implantsand their including tissues in very thin layers(Figs. 11-20). The specimens confirmed that, after a decade ofservice, the bicortical screws maintained an ex-

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carcerated the screws with no interposition of fi-brous tissue (Figs. 6-9) (27-29).Fascinating histological documentation comesfrom the autopsy specimen of the mandible of a75-year-old woman in whom the Norwegian den-tist Damal Johan Nyborg placed six bicorticalscrews to support a gold-resin bridge of tencrowns on March 10, 1980. The mandible was re-moved in toto from the skull of the patient, whodied 10 years later (February 15, 1990).


Figs. 6-9 Longitudinal sections of various implant areas with the integrating tissue (Cebus Apella). Masson’s trichrome stain; planarmagnification (Figs. 6, 7). PAS staining. 1: implant area. 2: newly formed peri-implant bone. 3: pre-existing bone (Fig. 8).

Close-up of the implant spiral (Masson’s trichrome stain – 400x) (Fig. 9).

6 7 8 9

10

1211 13 14 15

17

16

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Fig. 10 The mandible explanted (postmortem) from a female patient with six immediately loaded bicortical screws,after 10 years of service. Figs. 11-20 The block section series performed by Donath, which proved the absence of connective

tissue at the bone/implant interface (toluidine blue).

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cellent histological profile at the peri-implantmucosal seal and correct osseointegration with-in the bone tissue in which they had beenplaced (30).

Practical application of the Garbaccio screw

The insertion technique of the Garbaccio bicorti-cal screws was described and updated by the in-ventor himself in the 1980s. Two new types ofscrews were also designed during this period:1) the screw for distal lower edentulous areas fit-

ted with a longer nosepiece (diameter 1.2 mm)to ease insertion in the small space betweenthe two cortical bones and the mandibularcanal, and avoid the risk of nerve damage bythe threads;

2) the screw for the tuber area, with a longer tip(nosepiece) which increases the screw lengthto 35 mm and has a diameter of 5.5 mm.

The use of very thin drills, such as the Maillefertype employed in flapless surgery, is based on thepremise that minimizing surgical injury is crucial. Over the years, the shape of the threads was alsoperfected to permit effective distraction of thebone tissue cut in a centripetal fashion (towardthe surgical bore), thus employing the cut trabec-ulae - which would otherwise be lost - as an allo-graft. Nevertheless, the Garbaccio screws became sowidespread and were employed in so many differ-ent situations that they were successful even incases where the conditions were not ideal forblindly using the original Garbaccio technique.Often, especially when speed is of the essence,such as cases in which multiple implants must beplaced in a single surgical session, the sequencerequires the execution of a small superficial hole,the use of a non-traumatic drill of 2.5 mm insert-ed up to the working length (corresponding tothe deep cortical bone), and the insertion of animplant at the same depth. This procedure en-sures a pace that makes it possible to completesurgery without overtiring the patient. As the pa-tient gradually realizes that the implants havebeen placed, he/she feels a sense of relief and re-gains energy. The subsequent steps, which are useful for theimmediate loading of the implants, are sometimeslaborious, but at the end of the surgery they areeasily endured by the patient who, although tired,is aware that the surgery has been completed and

the potential risk (nonexistent, but always viewedas such by anyone undergoing a surgical proce-dure) is over.

Clinical uses

The Garbaccio bicortical screw can be used incases of healed edentulous ridge, but also as animmediate post-extraction implant. It is an excep-tionally versatile implant that, when used basedon the proper surgical and prosthetic indications,provides sure results even when immediatelyloaded. It also promptly solves problems of parallelism,as the abutment can be bent during surgery. Thisfeature is particularly important because it per-mits placement of prostheses with a correct buc-co-lingual volume, avoiding dangerous stress onthe implants due to tongue expansion. In fact,incorrect positioning of the abutment can lead tothe manufacture of a prosthesis that is too big onthe side where the abutment is tilted, with anovercontour on the opposite side. This problemmust be noted promptly if the implant is goingto be loaded immediately with a temporary pros-thesis. Concerning the importance of addressingthe problem immediately, refer to publicationsthat specifically discuss the effect of the tongueon the osseointegration of endosseous implants(31-33). One of these reports notes: “The effectexerted by the tongue can be reduced by model-ing the temporary prosthesis placed on the im-plants in such a way that the volume occupiedinside the oral cavity is lower than that of theprevious teeth. The tongue, in fact, exerts lessstress if its expansion was previously thwarted bya larger volume” (33).The Garbaccio screw is one of a kind due to theease with which the post can be bent. There aretwo main reasons for this:1) deep anchoring that is always strong and se-

cure, deriving from the design of the apicalportion of the implant;

2) the use of Grade 2 titanium, a material nowrarely found on the market (2008). This screwis designed so that the three, four or five api-cal threads anchor the implant deeply, whilethe long shaft, which is more elastic than usu-al, permits:a) absorption of the stress originated by oc-clusal and masticatory movements;b) achievement of unparalleled osseointegra-tion, due to the fact that, unlike other types ofimplants, the metal’s modulus of elasticity is

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more similar to that of the housing bone. Thiselasticity prevents fracture of the Garbaccioscrew, which - tellingly - is a very rare occur-rence.

Implant bending can be performed with the sameinsertion key or pliers for lower root extraction.The “stump bender” designed by the author iseven better, as it permits more apical curvature. Bending is easier with immediate post-extractiveimplants, since the tunnel is deeper, the shaft islonger, and the implant is also stabilized by thelamina dura of the socket during bending (34).Bending should be performed gradually and gen-tly, moving in only one direction. It should bestressed that the studies done with computerizedmodels, according to which the curvature waspredictive of fractures, do not take into accountthat the procedure should be performed at thesurgical site (before osseointegration). Moreover,the tract being bent (bending must be angular toavoid cortical damage) is then integrated withinthe bone. Consequently, later fracturing will notoccur, unless improper torsion was applied dur-ing surgery.In fact, torsion caused by excessive rotation whenthe implant is at the bottom of its insertion site ismuch more dangerous. Such torsion occurs withvery dense bone, and when the indications aboutthe correct working length during drill insertionhave not been followed. With these screws it is al-so important to work systematically, even if theyare more “forgiving” than other types of implants.If the implants are to be welded together with atitanium wire (or bar) and Mondani’s intraoralsolder (35, 36), this volume should also be takeninto account, because when the wire or the barare placed lingually they increase the structure’slingual volume. In this case, the curvature shouldbe slightly accentuated buccally to avoid manu-facturing an overcontoured prosthesis on the lin-gual side, which will create modeling problemsand food stagnation.

Speed of application

The Garbaccio screw facilitates the surgical pro-cedure, as it is designed to find the tunnel extre-mely easily and permit subsequent engagement,proceeding toward the bottom of the surgical sitewithout any obstacles (37, 38).Rotation with the finger key does not interferewith the tactile sensitivity required to detect un-foreseen obstacles to screw penetration, whichcould cause torsion of the implant neck. In fact,

rotation of the 30-mm-long bicortical screw is as-sociated with torques that Garbaccio had alreadytaken into account and solved before presentingthe screw.Other monoblock implants with emerging screwsthat are currently on the market continue to showunsolved torsional problems, due to the design oftheir spirals and the abutment size. Such featurescan cause immediate or later fracture of the neckif the implant encountered obstacles during deepinsertion. The obstruction of implant rotation isoften not perceived by the oral surgeon, who un-fortunately continues to operate to reach theworking depth, leading to possible fracture of theimplant.The usual solutions adopted by implant manufac-turers to overcome these problems are high-gradetitanium and larger implant diameters. With thisapproach, however, implant versatility is lost andas a result its indications are also diminished. 1) A rigid implant is not suitable for areas with

elastic bone properties such as the first andsecond lower premolar regions, as already re-ported in literature (39). The elastic deforma-tion of the mandible was studied extensivelyby many authors during the 1970s and 1980s(40-49). Some of them tried to followmandibular flexion using cylindrical implantswith a large diameter, namely the IMZ implantsystem. The ensuing solution, the “intramobileelement” made of Teflon, which was supposedto cushion the implant/prosthesis interface,was not very successful in clinical practice.The use of low-grade titanium implants with asmaller diameter - such as the Garbaccio screwis still the only viable solution for treating thefirst and second premolar region, permittingcomplete osseointegration of the endosseousportion of the implant. With rigid fixturessuch as submerged implants, which must nec-essarily be made of high-grade titanium due tothe critical thickness at the implant/abutmentconnection area, angular bone defects are reg-ularly observed. This represents a lack of inte-gration at the superficial areas, rather than re-sorption per se.

2) Very rigid materials make mechanical correc-tion of parallelism impossible. The implantmust thus be perfectly aligned during place-ment, but this is not always possible.

The Garbaccio screw can be used to treat mostanatomical morphologies, making it an ideal im-plant both for neophytes as well as experiencedimplantologists who want to supplement theirimplant instrumentation.


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Naturally, there is also a drawback, namely thesmall size of the abutment, which prevents theapplication of prostheses with crown diameter ofmore than 5 mm. This is why the Garbaccio screwis ideal for the lower incisor area, and suitable forthe premolar and canine regions, but not for themolar areas. For the latter, the type of implantmust be chosen on the basis of surgical and indi-vidual biomechanical parameters, opting for alarge diameter implant where possible.

Clinical cases

The following are documented clinical cases il-lustrating the use potential of the Garbaccioscrews.

Case one Lower incisors (Figs. 21-24)Placement of three bicortical Garbaccio screws fol-lowing the extraction of 4.2, 4.1 and 3.1, and im-mediate loading with a temporary prosthesis, fol-lowed by a definitive prosthesis. In the lower inci-sor region, the use of implants with a diameter of2-2.5 mm was advisable to promote correct papil-lary architecture (50).

Case twoLower incisors (Figs. 25-30)Extraction of a mobile lower incisor and immediate

Fig. 21 Three Garbaccio screw implants placed following extractionof three lower incisors.Fig. 22 Appearance of the peri-implant mucosae after healing.Fig. 23 Cemented definitive prosthesis.Fig. 24 X-ray.

Fig. 25 The mobile tooth 4.1.Fig. 26 The linguoverted bicortical screw placed immediatelyafter extraction.Fig. 27 Mechanical bending permits immediate parallelismwith the adjacent teeth.Fig. 28 The temporary prosthesis cemented after surgery.Fig. 29 The case at the three-year checkup.Fig. 30 X-ray at 5 years.

24

21 22

25 26

27 28

29 30

23

replacement with a Garbaccio bicortical screw im-plant. Mechanical bending of the abutment and im-mediate loading with the crown of the extractedtooth. Clinical and radiographic checkup a fewyears after surgery.The patient decided to keep the natural crown usedfor the immediate loading of the implant.

Case threeAbutment bendingin the upper arch (Figs. 31-34)Abutment bending in the upper arch (Figs. 31–34)Placement of a Garbaccio bicortical screw implantfollowing extraction of the upper left lateral inci-sor, during complete rehabilitation of the upperarch.The Garbaccio screw was chosen in order to cor-rect parallelism immediately; submerged screw im-

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31 3332 34

Fig. 31 Implant abutment before mechanical bending.. Fig. 32 Parallelism has been attained. Fig. 33 X-ray of the 1.2-1.3 area.Fig. 34 OPG of the finished case.

35 3736

38 39 40

Fig. 35 Eight Garbaccio screw implants were placed in the areas 4.4 -3.4. Note the linguoverted abutments.Fig. 36 Correct parallelism.

Fig. 37 Soldering of a splinting wire and suture at the end of the surgery. The implants were immediately loaded with temporary prostheses.Fig. 38 Appearance of the mucosae 3 months after immediate loading, during cementation of the fixed definitive prosthesis.

Fig. 39 Cemented definitive fixed prosthesis.Fig. 40 OPG of the finished case.

plants and a Pasqualini blade implant were usedfor the rest of the arch (51, 52).

Case fourComplete lower prosthesis on implants with a welded splinting wire (Figs. 35-40)In this case, eight Garbaccio screws were placed inthe inter-foramen area, and two blade implants inthe ramus region using the DEE technique (DistalEndosseous Extension) (53, 54) in areas 4.6 and3.6.For correct placement of the prosthesis, the abut-ments of the screw implants were bent, taking into

account the space taken up by the splinting wire, asclearly shown in the photographs.

References

1. SCIALOM J. Implants aiguilles (pin implants). J Oral Im-plant Transplant Surg 1965;11:18-23.2. SCIALOM J. Pin implants at point of entrance. Rev Odon-toimplantol 1967 May;6:22-30.3. SCIALOM J. Pin implants as elements of attachment. SO-LAIAT 1967 Jul;1(1):87-94.

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4. SCIALOM J. Conservative implantology. Rev Odontoim-plantol 1967 Dec;10:34-9.5. SCIALOM J. Are all implants functional? Rev Odontoim-plantol 1968 Nov;19:25-6.6. SCIALOM J. Answers to questions relating to needle im-plantation. Rev Odontoimplantol 1972 Oct-Dec;6(46):7-14.7. PASQUALINI U. Endosseous implants. Protection of repa-rative osteogenesis with the “screw stump”. Dent Cadmos1972 Aug;40(8):1185-94.8. PASQUALINI U. Endo-osseous implantations: clinical, hi-stological and anatomic-pathological studies. Dent Cadmos1971;39(6):886-90.9. GARBACCIO D. The Garbaccio bicortical self-threadingscrew. Riv Odont Impl 1983 Jan-Feb;(1):53-6.10. GARBACCIO D. Endosseous self-threading screws: bio-mechanical principles, surgical technic and clinical results.Dent Cadmos 1981 Jun;49(6):19-31.11. CHENAUX G., CASTAGNOLA L., COLOMBO A. Intra-ligamentary anesthesia with the “Peripress” syringe. SSOSchweiz Monatsschr Zahnheilkd 1976 Nov;86(11):1165-73.12. CASTAGNOLA L., CHENAUX G., COLOMBO A. Intra-ligament anesthesia with the Peripress syringe. Dent Cadmos1976 Nov;44(11):7-14.13. CASTAGNOLA L., COLOMBO A., CHENAUX G. Peri-press: a new concept in dental anestesia. Odontoiatr Prat1977 Jan-Mar;12(1):5-13.14. CASTAGNOLA L., CHENAUX G., COLOMBO A. Intra-ligamental anesthesia using the Peripress syringe. Quintes-senz 1980 Jul;31(7):11-6.15. GRAFELMANN H.L., PASQUALINI U., GARBACCIO D.Das selbstschneidende, bicortical abgestützte Schraubim-plant. Biomechaniches Prinzip, chirurgische Tecnick und kli-nische Resultate. Orale Implantologie 1981;9:103-22.16. BOBBIO A. Implantoprotesi a palizzata. Riv Odontosto-matol Implantoprotesi 1988 Ago;(8):110-15.17. BOBBIO A. Immediate endosseous implantation withscrews. Dent Cadmos 1984 Mar;52(3 Suppl):53-9.18. CORNEO E.J. Impianto di Garbaccio-Ricerche istologi-che, con relativo commento. Riv Odontostomatol Implanto-protesi 1988 Mar;(3):126-32.19. GARBACCIO D., GRAFELMANN H.L. Die Bicortical-schraube fur den Einzelzahnersat. Orale Implantologie1986;3.20. GARBACCIO D. The Garbaccio bicortical self-threadingscrew. Riv Odontostomatol Implantoprotesi 1983 Jan-Feb;(1):53-6.21. GARBACCIO D. La vite autofilettante bicorticale: esten-sione alle zone edentule distali superiori ed inferiori. DentCadmos 1983;51(2):11-6.22. GARBACCIO D. Endosseous self-threading screws: bio-mechanical principles, surgical technic and clinical results.Dent Cadmos 1981 Jun;49(6):19-31.23. GARBACCIO D., FREZZA G. L’impianto ideale. RivOdontostomatol Implantoprotesi 1990 Giu;(6):130-5.24. GROTOWSKI T. When is an implant indicated? Need for

a new approach. Dent Cadmos 1990 Nov-15;58(17):89-90,92, 94-5.25. LA FORGIA D., MANGINI F., MARINI N., MONDANI P.Un impianto alla volta: la vite autofilettante del dott. Garbac-cio. Riv Odontostomatol Implantoprotesi 1986 Set;(9):60-1.26. PANZONI E. Chirurgia preprotesica ed implantologia.Vol. 3. Milano: Masson; 1987. p. 7.27. SARNACHIARO O., GARCIA J.L. Estudio histológico enmandibulas de “Monos cebus” con implantes endo osseosespirales (12 meses). Int J Oral Implantol 1985 Apr;(4):25-9.28. SARNACHIARO O., BONAL O., GRATO BUR E., VAA-MONDE A. Istologische untersuchung des selbstschneiden-den Garbaccio – titan schreibeimdlantats (bicortical schrau-be) in Tierversuch. Orale Implantologie 1986 Dic;(12):13-32.29. SARNACHIARO O., BONAL O., Vaamonde A. Behaviorof periimplant tissue in situ and the new tissue that sur-rounds endosteal titanium screws. Implantologist1986;3(3):43-9.30. DONATH K., NYBORG I. Esame istologico (post-mor-tem) di una mandibola con sei viti bi-corticali. Riv Odonto-stomatol Implantoprotesi 1991 Ago;(8):8-65.31. PASQUALINI U. Le patologie occlusali. Eziopatogenesi eterapia. Milano: Masson; 1993. p. 29-38.32. DAL CARLO L. Influenza della lingua sull’integrazionedegli impianti endossei. Doctor OS 2003 Mag; 4(5):479-84.33. DAL CARLO L., BRINON E.N. Influencia de la lengua enla integraciòn de los implantes intra-òseos. Revísta EspanolaOdontoestomatoiògica de Implantes 2004 Abril-Junío;2(XII):102-11.34. DAL CARLO L. Impianti a lama e vite emergente: aspet-ti chirurgici e protesici. Proceedings of the 6th InternationalALSL Congress; Bologna, Italy. 2005. Verona: Litozetatre;2005.35. MONDANI P.L.,MONDANI P.M. Il perno intraosseo au-toforante ed autodirezionale di Mondani. Riv Odontostoma-tol Implantoprotesi 1990 Mar;(3):20-27.36. VANNINI F., NARDONE M. Emerging transmucosal sin-gle stage implants with electro-welding and immediate loa-ding. Annali di Stomatologia 2004 July-September;LIII(3):129-35. 37. GARBACCIO D. La vite di Garbaccio per impianto im-mediato. Dental Post 1974 Mar;(3):19-20.38. GARBACCIO D. Vite autofilettante bicorticale di Garbac-cio. Dental Post 1974 Apr;(4):7-13.39. DAL CARLO L. Utilità dell’implantologia emergente. TheNotes 2001;1:5-8.40. DE MARCO T.J., PAINE S. Mandibular dimensionalchange. J Prosthet Dent 1974 May;31(5):482-5.41. GOODKING R.J., HERINGLAKE C.B. Mandibular flexu-re in opening and closing movements. J Prosthet Dent 1973Aug;30(2):134-8.42. Köllner H.J. The registration of the retrusive closing pha-

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se and its effect on the mandible. Zahn Mund KieferheilkdZentralbl 1978;66(8):792-6.43. MARX H. Die funktionsbedingten elastischen Deformie-rungen der menschlichen Mandibula. Mainz: Med Habil-Schrift; 1966.44. MARX H. Die elastische Deformation der Mandibula un-ter der Funktion. Fortsch zahnaerztl Implantal 1985;1:264-65.45. MCGLUMPHY E.A., CAMPAGNI K.W.V., PETERTSONL.J. A comparison of the stress transfer characteristics of adental implant with a rigid or a resilient internai element. JProsth Dent 1989;62:586-93.46. NEY T., SCHULTE W. Implantatbelastung durch Kno-chendeformatíon im interforamínalen Bereich des Unterkie-fers bei funktianeller Beanspruchung. Z Zahnaerztl Implantol1988:4:109.47. NIEDERDELLMANN H., UHLIG G., JOOS U. Das elasti-sche Formverhalten der Mandibula unter funktioneller Bela-stung. Quintessenz 1981;32:1113-17.48. OMAR R., WISE M.D. Implications of mandibular flexu-re. Oral Rehab 1981;9:209-21.49. SETZ J., WEBER H., BENZIG U., GEIS-GERSTORFER J.Klinische Untersuchungenzur funktioneilen Belastung steg-

verschraubter Impiantate. Z Zahnaerztl Impiantol 1989;5:24-28. 50. BIANCHI A., SANFILIPPO F., ZAFFE D. Implantologia eimplantoprotesi. Basi biologiche. Biomeccanica. Applicazionicliniche. Torino: UTET; 1999. p. 414-417.51. ACKERMANN R., BADER J., BERNKOPF A., CEFFA G.,COLOGNATO G., DEL MONACO F., FERREOL P., GUA-STAMACCHIA C., IMPERIALI G., MORRA GRECO A., MU-RATORI G., PASQUALINI U., PIRAS E., TOFFENETTI F.,TRAMONTE S.M. Implantologia Oggi. Milano: EdizioniCADMOS; 1974. p. 1-247.52. RICCIARDI A. Nine years with Pasqualini implants: a fullmandibular arch. J Oral Implantal 1980;9(1):83-94.53. DAL CARLO L. Nuova tecnica per l’inserzione di impian-ti a lama: Estensione Distale Endoossea. Dent Cadmos2001;16:41-49.54. DAL CARLO L. Endosseous distal extension: a new te-chnique that is useful to save clinical cases characterized byscarceness of cancellous bone tissue in the lower distal sec-tor. Stomatafoghieski Journal (Minsk) 2002; 3(8).

Figs. 21–40 Courtesy of Luca dal Carlo


TREATISE OF IMPLANT DENTISTRY CHAPTER XIII

A ll two-step implants require a consolidationperiod that forces patients to remain edentu-lous or endure the discomforts (and risks) of

wearing temporary removable prostheses (1, 2).Other types of implants, such as soldered needlesand self-tapping, bicortical, rapid and MUMscrews, can instead immediately offer the aestheticand functional advantages of fixed and immediatetemporary prostheses (3-7). With the exception ofvery particular cases, patients are always dischargedwith temporary fixed prostheses for cosmetic rea-sons, with no harm to the supporting implants. Inany case, the procedures should be performed re-specting the static and dynamic occlusal principlesthat are crucial for the stability of natural teeth, inaddition to the occlusal static principles applicableto the “emerging” implants that have been discus-sed. In this section we will briefly examine theseprinciples, which have been extensively described,demonstrated and discussed in Le patologie occlu-sali. Eziopatogenesi e terapia, which is recommen-ded to readers who would like to learn more aboutthis science, as it is the cornerstone of dentistry asa whole, including implantology.

Constructing fixed temporaryprostheses

Temporary prostheses on implants, as on naturalteeth, can be traumatic if they fail to respect staticand dynamic occlusal balance. We will summarizebasic and crucial recommendations for temporaryor fixed implant and prosthetic rehabilitation.

Front single-tooth implant1

The replacement of a single front tooth represents themost “classic” implant indication. The immediate

loading of front single-tooth implants requires com-prehensive knowledge of occlusal physiology, whichcan be summed up based on two indications.1) No front tooth, including canines, should have

static contacts with the opposite teeth. Thesecontacts are pathological due to the differentloading direction with respect to the root incli-nation.

2) Premolars and molars are the only teeth that cansafely withstand static occlusal force, since theydistribute the load along the main axis of theroots.

The purpose of the practical examples that follow isto give the reader insight into these aspects. Patientswho have lost or are about to lose one or more frontteeth due to occlusal trauma frequently ask for tem-porary prosthetic rehabilitation, as in the case of thetypical patient shown in the following illustrations.Replacing the tooth that is about to be expelled witha single-tooth implant and crown placed withoutprevious occlusal rebalancing of both arches wouldsubject the new restoration to the selfsame expulsivecauses, thus slating the implant for failure.Those who are unaware of the importance of oc-clusal balance would likely attribute failure to thefact the single-tooth implant was not splinted to theadjacent teeth or, as too often happens, to the factthat submerged implants were not been employed,and/or to microbial causes.The following series of photographs (Figs. 1-24)shows that, after removal of the premature distalcontacts leading to expulsion of the central incisorby traumatic mandible translation, it was possible

Introduction

168

1 In order to avoid repetitions and made the chapter easier to follow, theterm “single-tooth implant” is used broadly to indicate thereplacement of a single tooth both with a single implant or with severalimplants joined to form a single prosthetic abutment (screw stabilizedwith one or more needles, tripods made of needles, two screws).

IMMEDIATE FIXED TEMPORARY PROSTHESES AND DEFINITIVE PROSTHESES ON IMPLANTS

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Immediate fixed temporary prostheses and definitive prostheses on implants XIII

1 2 3

4 5

7 8

6

9

10 11 12

Fig. 1 Left upper central incisor in the expulsive phase (1984). Fig. 2 Radiographic validation. Fig. 3 Premature contacts in centricocclusion after condylar repositioning in hinge axis. Fig. 4 The arrows point the premature contacts caused by malocclusion due to

previous extractions. Fig. 5 The premature contacts in centric occlusion prevent swallowing, and the mandible shifts forward in order tofind acentric contacts that will allows a tongue positioning suitable for peristaltic movements. Fig. 6 Mandible translation causes

pathological contact of the incisor with subsequent mobilization and expulsion. Fig. 7 In order to obtain correct occlusal balance, selectivegrinding is required before any oral implant rehabilitation. Fig. 8 Surgical phase: note the bone lesion.

Fig. 9 X-ray image of the Garbaccio bicortical screw placed according to the longer axis of the available bone.Fig. 10 Rendering of the surgical screw insertion path. Fig. 11 To increase implant retention we placed

a stabilizing needle with a divergent and palatal axis with respect to the adjacent tooth (1984). Fig. 12 The bone defect is filled with non-resorbable hydroxyapatite granules (to prevent cosmetic problems in the area).

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13 14

16

15

22 2423

17 18

2019 21

Fig. 13 Lyophilized dura mater free “graft” to reduce possible bone resorption in the area of the repositioning flap schisis.Fig. 14 Suture. Fig. 15 Radiographic checkup: the arrow at the bottom points to the coronal welding of a small titanium bar,

placed for prosthetic reasons (to increase the volume of the external abutment). Fig. 16 Immediate temporary crown after surgery (1984). Fig. 17 Temporary crown and healthy stippled mucosa at one month. Fig. 18 Definitive gold-porcelain crown

(1985). Fig. 19 Checkup X-ray (1985). Fig. 20 Traction test with 5 orthodontic elastics: note the ischemic finger,demonstrating the great pressure applied. Fig. 21 Checkup after 16 years (2000). Fig. 22 Clinical appearance (2000).

Fig. 23 Another checkup (2004). Fig. 24 Radiographic validation after 20 years (2004).

to replace the tooth with a single-tooth implantwith an emerging abutment. Despite the scarceresidual bone crest, this permitted immediate tem-porary loading and subsequent placement of a sin-gle definitive gold-porcelain crown, which proved

its validity at the regular checkups performed overthe next twenty years (1984-2004).

The importance of dynamic occlusal balanceThe second part of Le patologie occlusali. Eziopatoge-

reported that the trouble with the left implant startedimmediately after placement of an amalgam filling ona molar by her dentist (who also referred her to us).With the aid of a Pasqualini stopper, we detected asingle premature contact - on the “beautiful” fillingmade by our colleague! Removing it sufficed to re-es-

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nesi e terapia is devoted to the physiology of dynam-ic balance and the pathological consequences of itsabsence.The 430 pages that the book devotes to the topiccan be summed up in a single rule, which we willsupplement with significant practical examples inorder to demonstrate the importance of this knowl-edge in virtually every branch of dentistry, particu-larly implantology.

❚ Like the other front teeth, canines should haveno static contact with the opposite teeth. How-ever, they can easily withstand dynamic con-tacts, protecting - during their lateral move-ments - all the other teeth in the arches from anypathological contact. This function is thusknown as “canine disclusion.”

Due to lack of space we cannot expand on the“non-existence of the condylar guide,” the disclu-sive physiology of the “maximum moment” of thecanines, their peculiar bone stabilization in the ju-ga alveolaria, and the reason for the thicker enam-el layer that protects the surface of their dynamicdisclusion path during Bennett movements. Thisdemonstration will thus rely on the sole evidence ofthe examples presented here, which must be exam-ined carefully.

Clinical exampleA young woman with congenital agenesis of the up-per lateral incisors, orthodontically treated withdistalization of both canines to create the space fortwo single implants in order to replace the missingteeth (Figs. 25-43) (8). After the flapless insertion of two bicortical screws,two temporary crowns were placed immediately,following careful check of the absence of prematurestatic contacts with the antagonist teeth. After healing of the periodontal soft tissues, thetemporary resin crowns were replaced by two sin-gle porcelain ones, made respecting the same oc-clusal principles (static and dynamic). The youngwoman was observed three years later, as she wasworried about the sudden mobility of the left im-plant and the severe gingival irritation of the area.The X-rays showed the different osseointegration pat-tern between the stable right implant and the left mo-bile one, where an initial peri-implant bone resorp-tion was detected. The different superficial appear-ance of the related mucosae was also apparent. Thelateral leftward movement showed the loss of caninedisclusion with premature contact on the compro-mised single-tooth implant, while the contralateralcanine exhibited physiological disclusion. The patient


25

27

28

26

Fig. 25 Agenesis of the lateral incisors in a young patient (1986).Fig. 26 X-ray of two quick screws.Fig. 27 The two single-tooth implants were placed duringflapless surgery (1986).Fig. 28 The two definitive gold-porcelain crowns.

tablish centric occlusion of the mandible, and itsolved the translation that had shifted it forward andprevented left disclusion.At the one-month checkup the patient showedcomplete healing of the soft tissue inflammationabove the implant, which had regained its completeoriginal stability. Since the previous dynamic trau-

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29 30 31

32 33 34

35 36

38

37

39 40

Fig. 29 Three years later the single-tooth left implant appears compromised and some papillae are bleeding (arrow). Fig. 30 Theradiographic checkup shows resorption of the peri-implant bone around the threads. Fig. 31 Manual condyle repositioning in the

hinge axis, which immediately reveals the presence of instable distal contacts. Fig. 32 The arrow points to trauma of the left single-tooth implant following translation in static occlusion. Fig. 33 The trauma (arrows) is also worsened by the loss of canine disclusion

(dynamic trauma). Fig. 34 The occlusal plane of the upper arch shows good amalgam fillings made by a colleague.Fig. 35 Occlusal check with the aid of the Pasqualini stopper. Fig. 36 The premature contact marked on the occlusal surface of

an amalgam filling must be removed immediately to restore both the centric and dynamic balance. Fig. 37 The pathologicalsituation before restoration of the occlusal balance. Fig. 38 The new morphology of the peri-implant mucosa, healed “simply” after

occlusal balance was restored. Fig. 39 Check of canine disclusion. Fig. 40 Replacement of the old crown (1989).

ma displaced the crown and created a diastema, theformer was replaced and the occlusion checked.Comparison of the two X-rays (Figs. 30, 43), takenat the time of implant involvement and after crownreplacement, is fascinating, showing the remarkablerecovery of the peri-implant bone tissue one yearafter occlusal rebalancing.

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44 45 46

47 48 49

41 43

Fig. 44 Loss (iatrogenic) of the canine of this very young patient (1987). Fig. 45 The lack of canine disclusion determines severedynamic premature contacts. Fig. 46 The temporary “spider” wore by the patient strictly for cosmetic reasons (1987) and with no dynamicfunction. Fig. 47 The X-ray shows the post-extraction socket area. Fig. 48 Flap incision. Fig. 49 The flap detachment shows boneloss along the juga alveolaria of premolar and incisor (horizontal atrophy) caused by the lack of canine disclusion, and unquestionably not due

to bacterial infection. Fig. 50 Two surgical phases. Fig. 51 Use of the self-centering drill.Fig. 52 The 3.1-mm MUM implant before insertion in the surgical tunnel.

50 51 52

Fig. 41 Fig. 41 The new crown shaped according to the morphology of the healed epithelium (1989). Fig. 42 Canine disclusion.Fig. 43 The X-ray taken after one year (1990) underscore the remarkable neoformation of peri-implant tissue.

Note: compare to the X-ray in Figure 30.

42

Single-tooth implants on caninesThe next photographs show that single-tooth im-plants on canines require strict observance of thesame occlusal principles (Figs. 44-68), the only dif-

ference being that on the immediate temporaryprostheses both static and dynamic contacts mustbe excluded as a precautionary measure, as theycan be harmful during integrating osteogenesis.

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61 62 6463

57 58 6059

Fig. 53 Implant correctly placed up to contact and penetration of the deep cortical bone.Fig. 54 The radiographic checkup shows successful bicorticalism and the use of a 1.1-mm self-centering drill for the subsequent placement

of a stabilizing needle. Fig. 55 Insertion of the stabilizing needle (personal technique).Fig. 56 Intraoral soldering. Fig. 57 Radiographic checkup: note the bicorticalism of the two implants.

Fig. 58 The single-tooth implant. Note the soldering mark and the loss of bone tissue on the premolar (arrow).Fig. 59 Immediate temporary crown upon completion of surgery. Since this tooth is a canine, it requires al least 2 months of “resting” after

complete osseointegration before it can regaining its physiological disclusion function.Fig. 60 Healing of the soft tissues at 60 days indicates complete osteogenesis. Fig. 61 The subgingival preparation of the implant

abutment and impression taking. Fig. 62 Perfect healing of the peri-implant mucosa “despite” the presence of a bifurcation.Fig. 63 Definitive gold-porcelain crown immediately after placement.

Fig. 64 Radiographic checkup (1987). Fig. 65 Correct disclusion and the absence of dynamic premature contacts.Fig. 66 Palatal view. Fig. 67 The same canine 21 years later (2008).

Fig. 68 The X-ray shows only mild initial conical resorption (2008).

53 54 5655

65 66 67 68

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The temporary periodontal involvement of the oth-er teeth of the arch, due to the absence of caninedisclusion, will be offset by their quick return tonormality after physiological disclusion is restoredwith the definitive gold-porcelain crown placed onthe single-tooth implant after osteogenesis of the in-tegrating tissue has been completed. Close attention should be paid to the next case,which we consider very interesting from an educa-tional standpoint. It demonstrates that even crownson single-tooth implants in the canine area mustbear the dynamic contact during disclusion. Vascu-lar fragility, marginal gingival hypertrophy and theevident horizontal bone atrophy affecting the adja-cent teeth disappeared a few weeks after the crownwas cemented on the canine and disclusion was re-stored. The crown has been in service for manyyears, and is perfectly functional and stable.

Single-tooth implant in the lower front areaThe next case shows the favorable evolution of asingle-tooth implant replacing a lower lateral inci-

sor, consisting of a single 2.6 mm MUM implantwithout balancing needles, as no other solutionswere feasible due to the narrowness of the availablespace (Figs. 69-93). The photographs show the ab-sence of peri-implant gaps, which can instead benoted next to the root of the natural central incisor,where the pathological widening of the periodontalspace was appreciable (1991).The placement of a provisional crown on a single-tooth implant with no lateral stabilization, such as theone in question, could have been risky, but the crownwas splinted to the adjacent teeth - which were stillstable - via contact areas that acted as natural “welds.”The temporary crown on the single-tooth implant wasalso checked for the presence of pathological contacts,both static and dynamic; the same precautions weretaken when shaping the definitive porcelain crownthat was later cemented to the implant abutment.However, the cementation caused a slight height in-crease due to the incompressibility of fluid cements,which can happen on occasion. This was subse-quently eliminated along with premature dynamic

73 74 7675

77 78 79

69 70 7271

Fig. 69 Loss of the right lower lateral incisor (1991). Fig. 70 The X-ray highlights a pathological increase of the periodontal space of thecentral incisor adjacent to the edentulous area (arrows). Fig. 71 The arrows point to enamel abrasion, sign of dynamic trauma due to

displacement of the lower canine. Fig. 72 Flap detachment and preparation of a surgical tunnel in a very thin bone. Fig. 73 Placement ofa 2-mm MUM implant at the neck. Note (arrow) the transparency of the labial bone. In this case, flapless surgery would have been difficult andwould probably have culminated in failure. Fig. 74 Cut and preparation of the abutment. Fig. 75 X-ray (1991). Fig. 76 Suture andimmediate temporary crown. Fig. 77 Check of the disclusion. The arrow points to a dynamic premature contact that will be removed later.

Fig. 78 The temporary crown and mucosal healing. Fig. 79 Before placement of the definitive crown.

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contacts on the contiguous lateral incisor (9). Follow-up X-rays taken two years later demonstratethe resolution of periodontal disease along thewhole root of the natural incisor and perfect os-seointegration of the MUM implant.What we have said so far about the immediate load-ing of front upper and lower implants - single ormultiple - is of little value if static occlusion is notborne by the distal teeth, molars and premolars, inocclusal balance.

In the absence of molars and premolars or whenthey are present but the antagonist tooth is missing,we usually observe mobile and compromised frontteeth that are often still in place for purely cosmet-ic reasons. In such cases, we proceed as follows:1) we initially place the distal implants without ex-

tracting the mobile front teeth;2) after 2–3 weeks, when the surgical wounds of the

mucosae have reached a satisfactory level of initialhealing, we extract the front teeth and replace

80 81 82

83 84 85

86 87 88

Fig. 80 Definitive gold-porcelain crown (1991). Fig. 81 Interdental contact points are crucial, since placement of a stabilizing needle isunfeasible due to reduced space. Fig. 82 Occlusal contact marking with articulating paper, to check for the presence of premature

contacts in centric occlusion. Fig. 83 The two black dots (arrows) indicate the corrections to make on the incisal margins,both on the artificial crown and the natural tooth. Fig. 84 The correction.

Fig. 85 Canine disclusion (arrow) indicates the presence of a premature dynamic contact. Fig. 86 Use of “Red Indicator” dry self-molding varnish. Fig. 87 Lateral movement to the right. Fig. 88 The small premature contact (arrow) must be removed immediately

to avoid implant damage. Fig. 89 Disclusion in the incisor area is now free from premature contacts.Fig. 90 Lateral movement toward left. Fig. 91 The same case at a later checkup (1993). Fig. 92 The X-ray shows healing of the

periodontal damage along the root of the adjacent incisor, and the good osseointegration of the MUM implant.Fig. 93 Close-up of the healthy appearance of the mucosa (1993).

89

9390 9291

177

them with at least four implants, which are tem-porarily splinted using one or more bars solderedto the distal implants. We then take impressions ofthe whole arch, and one or two days later we placea temporary bridge fixed with definitive cement,carefully checking the load distribution along thewhole length, making sure that it has no harmfuleffects on the supporting implants.

In exceptional cases, when the patient can endurethe placement of all the distal and frontal implantsin a single session, we immediately take the impres-sion and place a temporary prosthesis, avoidingmultiple surgeries in two or three sessions (10-12).

Implant-anchored definitiveprostheses

Prostheses on implants should be manufacturedfollowing the same principles adopted for tradition-al ones: The crown borders should end below thegingival border of the implants, with intermediatepontics fashioned with a “flute beak” shape, and in-terdental spaces as similar as possible to thosefound between natural teeth.The introduction of “flute beak” pontics con-tributed to the elimination of both of the old “vault-ed” pontics and “hygienic” ones, which are nowgenerally constructed as a “flute beak” and are per-fectly functional, with no discomfort for the patient.The implant abutments should be made to permitplacement of definitive crowns, manufactured withthe classic protective profile of the gingival sulcusof the natural abutments. The fact that crowns onimplants also end below the gingival margin servesboth cosmetic and hygienic purposes, since thisfeature assures food removal from the critical im-paction area, and avoid its penetration if there aresteps or undercuts above the gum. The intermediate pontics should also be construct-ed with the self-cleaning “flute beak” profile. Theinterdental spaces of the prosthetic pontic shouldnot be too wide, not only because they are poorlytolerated by the patient but also because they arehygienically inadequate, since the tongue - expand-ing during deglutition - should be able to performcleaning and massaging action without pushing thefood bolus below the pontic (13-15). The wide interdental spaces proposed in some publi-cations represent a prosthetic throwback because, inthe name of a wrongful concept of mechanical clean-ing, they deprive the patient of the natural cleaningaction exerted by cheeks and tongue, forcing him/herto resort to specific devices such as waterpicks, inter-

dental brushes, electric toothbrushes and so on.Furthermore, we avoid the free-end saddle bridgesthat are suggested by these publications (16-30) toovercome the intrinsic limitations of the type of im-plants they recommend. In fact, all such extensionsare kept ridiculously below the occlusal plane andthus have a reduced masticatory function. Thesekinds of extensions are subject to modifications,which are required when the implants need to beplaced in areas that do not coincide with the originalsites of the missing teeth. These are all consequencesof the use of a single type of implant that does not al-ways permit implant placement in the site corre-sponding to the natural tooth that was lost (31).

Impression taking with implantabutments

Since there is no difference between the shape of pros-theses on implants and those on natural abutments(except for the fact that titanium is not caries-suscep-tible and can thus be undercut) the impression-takingtechnique is the same. The old method - which usedaluminum transfers for natural abutments and pre-made transfers for implants, and was the best avail-able at a time when impressions were taken usingcopper rings and Kerr thermoplastic paste - has nowbeen surpassed, in terms of precision, by modern im-pression techniques using retraction cords (also usedfor implant abutments) and elastomeric impressionmaterials, polyethers, silicones, etc.We have been using the latter technique alone formany years, and it is always employed after paral-lelism of the natural and implant abutments hasbeen achieved. We must point out that, unlike nat-ural abutments consisting of dentine, which is morefragile, implant abutments can be reduced more insize due to the higher resistance and incorruptibil-ity of titanium. Nevertheless, it is not always possi-ble to give the implant abutments an optimal incli-nation, since they are inserted in relation to theslope of the available bone crest and not based onfuture prosthetic needs. All abutments are prepared by taking care that thedrill tip will always reach the subgingival space,even around the implant abutments. Due to thetenacious apposition of the mucosa on the titaniumabutment surface, a few drops of local anestheticare almost always injected.Following insertion of the retraction cord to createa gingival sulcus, which is indispensable for eachtype of preparation, we take impressions of boththe implants and natural abutments.


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The antagonist dental arch impression is taken withquick-setting alginate, wrapped in a disinfectant-soaked paper towel and sent to the laboratory insealed plastic bags. The wax-bite occlusal registra-tion, taken by manual manipulation of the patient’smandible in centric relation, is extremely important.We have already mentioned Le patologie occlusali.Eziopatogenesi e terapia, but would like to empha-size the importance of respecting and/or restoringstatic and dynamic occlusal harmony for both nat-ural and artificial teeth, as it is fundamental for thelong life of any implant.

Cementation of implant abutmentsImplant abutments should never be fixed with tem-porary cement because of possible imbalance in theevent of partial decementation, nor with definitiveoxyphosphate cement since the adhesion betweengold and/or crown metal and titanium is not stable.Our protocol always calls for strong resin cement tofit the titanium abutments securely to the crowns,as once it is polymerized it will prevent decementa-tion. The use of fluid resin cements is indispensa-ble in order to avoid height increases, which arevery difficult to adjust. As soon as a change inheight is detected, the bridge must immediately beremoved and cleaned, and the entire proceduremust be repeated from scratch.For bridges or mixed prostheses supported by im-plants or natural abutments, we prefer concomitantcementation of the crowns on natural teeth withoxyphosphate, using glass ionomer cement for thecrown placed on titanium abutments2. The dental assistants (preferably two) should beused to working together, coordinating the differentpreparation times of the two materials (personaltechnique). It is also advisable to remove excessresin cement from the crowns immediately, becauseonce it hardens it will require finishing that is notonly difficult to perform but also imprecise.

Gold-resin versus gold-porcelain prosthesesAt every conference and hands-on course, there is aparticipant who asks the germane question ofwhether the prostheses should be made of gold-resinor gold-porcelain. The answer invariably depends onthe teacher’s opinion and experience. Both solutions(gold-resin and gold-porcelain) have valid indica-tions, but just as many serious contraindications.The reasons for using porcelain crowns have to dowith better aesthetics, longer life and the absence ofocclusal surface damage caused by abrasion or

overbrushing. In turn, the contraindications arerepresented by the risk of fractures of the porcelainor of the metal framework, which always have seri-ous consequences.Gold-resin prostheses are preferred because of thelower risk of fracture, better “occlusal cushioning”and progressive (and, according to many authors,desirable) compensatory abrasion.Currently we are seeing the comeback of compos-ite resins, which have been improved in strengthand resistance to fracture.

Prostheses on single-tooth implantsThe definitive prosthesis on single-tooth implantsshould always be made with single porcelaincrowns. The choice of porcelain is justified by thefollowing considerations.Since single-tooth implants replace single dental el-ements between natural teeth, they must resemblethe contiguous teeth from a cosmetic standpoint.No material can surpass the aesthetics, functionali-ty, duration and fracture resistance of single porce-lain crowns.Le patologie occlusali. Eziopatogenesi e terapia clari-fied that even single porcelain crowns must complywith the same static and dynamic principles of theteeth they are replacing, which are often lost due toocclusal imbalance disharmony. It would be inexcus-able if the crowns on single implants replicated thesame pathological conditions that caused expulsionof the natural teeth or caused new ones.Furthermore, single porcelain crowns on centraland lateral incisors (upper and lower) must be freeof lateral premature dynamic contacts, and possiblyprotrusive ones, the sole exception being canines,as they are the only teeth in the arch that can with-stand them, due to their position of “maximummovement” (see detail in Figs. 25-93). Like incisors, the canines must be free of static con-tacts, but they should be able to disclude all the re-maining teeth of both arches during lateral move-ments. In presence of Class II or III, or ectopic canines, dis-clusion is impossible. In this case, the teeth shouldbe checked to be sure that they are not subject topremature static contacts, since (preventive) ortho-dontic correction, which would theoretically beideal, is not always possible. The single crowns on premolars and molars, whichnaturally have static contacts in centric occlusion,should always be protected by canine disclusion,which should prevent dynamic interference. There-

2 A single type of cement (i.e. glass ionomer) can also be used both on natural and titanium abutments.

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fore, they must be checked to be sure that there areno premature dynamic contacts, which must becorrected using articulating paper and “Red Indica-tor” dry self-molding varnish, as described in Le pa-tologie occlusali. Eziopatogenesi e terapia. After cementation, it is crucial to verify that thereare no pathological premature contacts.

Partial prosthesisWhen partial prostheses are placed between sectorscomposed of sound natural teeth in occlusal balance,they should be manufactured in gold-porcelain orresin with gold occlusal surfaces, in order to match theelasticity and occlusal hardness of the other sectors.In the case of lower prostheses including the canine,it is advisable to manufacture at least the canine ingold-porcelain, which can easily be soldered to otherparts of the gold-resin prosthesis. The reason is thatthe labial resin surface would be subject to abrasion,preventing the tooth’s disclusive function3.

Complete fixed prosthesesNo rule can be advocated with respect to the choiceof porcelain versus gold-resin for manufacturingcomplete fixed prostheses, since their advantagesand disadvantages are compensated by their respec-tive features. What we propose to “smart” patients with fewer aes-thetic requirements is a canine-canine (or premolar-premolar) porcelain prosthesis joined with a gold-resin prosthesis with gold occlusal surfaces on the dis-tal teeth, an option that offers excellent functional andcost benefits. We never propose fixed porcelain worksif there the antagonist teeth are made of resin.For the long-term success of both types of prosthe-sis (porcelain and resin), knowledge of occlusalprinciples is crucial. These principles can be sum-marized as follows:1) concomitant static and centric contacts only on

the teeth distal to the canines;2) dynamic contacts only on the canines;3) all front teeth, canines included, must always be

free of pathological static contacts.

Complete fixed prostheses onimplants in place of dentures

For completely edentulous patients with sufficient-ly wide ridges, both in the front and distal areas (at

least up to the first molar), fixed rehabilitation istheoretically always possible. However, some fun-damental rules must be respected in order to avoidmistakes that could thwart rehabilitation efforts.1) In each arch, all surgery should be completed in

a single session, to immediately provide the pa-tients with a temporary prosthesis (fixed, if pos-sible) in occlusal balance.

2) The bone height should be checked with X-raysand/or CT, followed by assessment of the widthby means of occlusal and bucco-palato-lingualprobing. Targeted tomographic analysis andcalipers are very useful for this, also making itpossible to establish implant diameters in ad-vance.

The measurements are very useful both for flaplesssurgery as well as open surgery. Some areas that areseemingly suited for implant placement may in-stead be too thin to permit insertion. This unfortu-nate situation is even more embarrassing when itoccurs suddenly, thwarting and/or complicating thework that has already been done. These problemscan be almost always solved with needles or MUMimplants, balanced by means of the intraoral solder.The safest thing to do is to splint all the implantstemporarily with welded bars, in order to achieveuniform load distribution until placement of thedefinitive prosthesis. Another rule is never to attempt total rehabilitationof the upper arch if there are still good front teethin the mandible. In these cases, permanent rehabil-itation of the complete lower arch is required first,in order to avoid imbalance and expulsion of theupper prosthesis due to the presence of the frontteeth. If the remaining lower teeth are still anchored topartial removable prostheses, the absence of mu-cosal resilience should be carefully assessed, as itwill force contact with the more stable front teeth,sustaining the aforementioned imbalance.We must again stress the need for preventive reha-bilitation of the lower arch with a stable prosthesis.Otherwise, the patient will soon render even themost resistant prosthesis on implants unstable (de-stroying it), for the same reasons that led to mobi-lization and loss of the front teeth in the first place4.This will be followed by failure of the completeprosthesis on the residual teeth or instability of thecomplete denture, which he/she cannot tolerate.The patient will thus end up asking to have it re-placed with a more stable one on implants.

3 Zirconia-porcelain prosthetic elements have recently been used successfully, with excellent cosmetic results.4 Too often attributed to microbial causes and/or lack of hygiene.

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Implant-anchored removabledentures

So far we have examined the indications and con-traindications for replacing upper and lower den-tures with implant-supported complete fixed pros-theses. At this point, we will deal with the rehabil-itation of edentulous atrophic distal areas, wherethe successful anchoring of dentures to a few im-plants friction-fitted Dolder and Ackerman bars ortelescopic prostheses is still possible (21-25). Removable dentures on implants make it possibleto eliminate the palate from the upper prosthesisand manufacture less bulky lower dentures, thusmaking them more stable and functional.Any reference to partial removable prostheses goesbeyond the scope of this chapter. When they areconnected to implants, they can cause nothing butdamage, even if the most “inventive” connectionsystems are used.We will deal exclusively with complete removabledentures anchored to a few supporting implants.The patient will still be able to remove them, but af-ter they are anchored by “snapping” them onto theimplants or bars he/she will immediately perceivethe positive difference compared to common den-tures.

Manufacturing technique for removabledentures. Advantages and problemsWe must premise this section by noting that onlytwo-step implants (after completion of the osseoin-tegration phase) permit the placement of removabledentures and can withstand loading.Considering that this type of prostheses can beplaced only on completely edentulous subjects, thepatients should be advised that they will not be ableto wear them until the two-step implants are fullyconsolidated5,6.Osseointegration time varies according to the typeof implants employed; it is directly proportional totheir immediate post-surgical stabilization and in-versely proportional to the need for a later stabiliza-tion by including osteogenesis. The two steps need-ed for the implants are due to the fact that only afew patients are willing to endure - while toothless- both the time required for their osseointegrationand the shorter time needed for the mucosae toheal. Therefore, we are forced to place implants

with screwable abutments that do not interfere withthe base of the temporary dentures, which must beput back into the oral cavity after surgery, after theyhave been relieved in the areas above the implantsand the sutures.Postoperative swallowing and mucosal edema fol-lowing anesthesia will make the dentures unstable.Due to local pain, they are worn primarily for cos-metic reasons, at least during the first week. Unfor-tunately, as the pain caused by pressure subsides,the patient begins to use them for chewing, apply-ing adhesives that break the suture and displace themucosa detached for surgery. Healing, which wouldotherwise be very fast, is thus prolonged and oftenoccurs by second intention. After an initial healing phase, during which the mu-cosa adheres to the periosteum, relining and adjust-ments of the old denture are required, but belowthe relining material the mucosa may exert exces-sive pressure on buried implants, leading to mobi-lization and failure.

TroubleshootingMost professionals opt for submerged implants be-cause they consider them trauma-free and due tothe fact that the implants achieve consolidationwithout any problems. We have just examined thecauses of failures, due chiefly to the fact that afterdenture relining the implant site is no longer de-tectable with any level of certainty. This means thatthe prosthesis can be relieved only marginally,which can lead to unpleasant consequences.We advise patients to refrain from using adhesivesuntil suture removal and, even then, only after ourapproval. The waiting period required for definitiveosseointegration is not risk-free when the upperdenture is not stable on the remaining edentulousareas (especially the retromolar trigones) and thehard palate, and if the denture is not strongly re-lieved by the implants. A final piece of advice: do not use the old dentureunless strictly necessary. It is best to manufacture anew denture with optimal occlusal balance.

Removable lower prosthesesWhen the front sector of the mandible still has goodheight and cancellous bone above the basal one,implant placement does not require precautionsother than those recommended for manufacturingupper removable dentures. Very often, however, we

5 The term “consolidation time” is easier for patients to understand than “osseointegration time”.6 This “temporary disability” can be overcome using mini-implants placed in between the two-step implants (26, 27), allowing the patient to wear a

rather stable temporary prosthesis.

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need to rehabilitate atrophic mandibles that arevery low and are reduced to the basal bone. Such mandibles make any kind of effective remov-able rehabilitation almost impossible. The condi-tions of these patients are truly compromised, andprofessionals are forced to deal with very complexsituations. Several pre-prosthetic surgeries havebeen designed to provide edentulous ridges,vestibular fornices and/or the sublingual area withhigher retentive possibilities (28-34). With the two-step implants we achieve good resultsby following these precautions.1) We always employ two-step implants that are

specifically designed for this purpose and havevariable lengths and threads. Their diameters arealways suitable for the rehabilitation of suffi-ciently wide atrophic crests.

2) Incision of the mucosa is followed by minimalflap detachment, without lingual or buccal ex-tension, which is sufficient to visualize the oc-clusal crest surface. This approach prevents lac-eration of the small capillaries coming from theperiosteum, which would affect the already se-verely reduced venous and lymphatic flow.

3) The insertion tunnel is carefully prepared.4) The implants designed for compact bone have

large threads in order to bear the load, compen-sating reduced height with increased width Thethreads are very sharp, but could neverthelessimpact the tunnel walls. Therefore, this surgeryrequires a great deal of caution and patience,with the sequential use of tappers with progres-sively larger thread diameters up to the final di-mensions of the definitive implant, which willbe screwed in manually without using tappers.


94

95 96 97

98 99

Fig. 94 Case of severe atrophy of the upper maxilla. Fig. 95 Surgical phase in the placement of two-step implants.Fig. 96 Healing of the mucosae and bone tissue at 6 months. Fig. 97 Dolder bar screwed to the implants.

Fig. 98 The finished definitive overdenture. Fig. 99 Palatal view. Fig. 100 The final radiography.

Following insertion, the healing screw is put inplace and the mucosa is sutured, making surethat the upper part of the screw protrudes onlyslightly from the mucosa or is completely sub-merged. Stress protection is achieved by follow-ing the same rules outlined for the upper im-plants, relieving the denture only well above theimplants.

5) Implants designed for the compact bone can beloaded after three months without the risk ofmobilization. Once the healing screws have beenremoved, and the abutments placed and paral-lelized, the supporting bars for denture retentionare added.

Conclusions

The numerous details sketched out here may seemexcessive, but we are convinced that they are nec-essary for the success of these types of removabledenture. Indeed, when well executed these den-tures allow patients to enjoy stable, effective, andlong-lasting artificial dentition (Figs. 94-100, 101-107, 108-113).

100

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101 102 103

104 105

106 107

108 109 110

111 112 113

Fig. 108 Another case successfully treated with two-step implants. Fig. 109 Close-up of the resin block of the positioning transfers withDuralay. Fig. 110 The impression. Fig. 111 The two screwed bars. Fig. 112 Finished case. Fig. 113 The final radiography.

Fig. 101 Lower edentulismtreated with 4 two-step implants.Fig. 102 The screwed bar.Fig. 103 The overdenture.Fig. 104 The same case,upper maxilla; it was alsotreated with two-step implantsand a bar.Fig. 105 The two prosthesesanchored to the bars.Fig. 106 View of the upperoverdenture without the palate.Fig. 107 Radiography of thefinished case.

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References

1. BRÅNEMARK P.I., HANSSON B.O., ADELL R., Breine U,Lindström J, Hallén O, Ohman A. Osseointegrated implantsin the treatment of the edentulous jaw. Experience from a 10-year period. Scand J Plast Reconstr Surg Suppl. 1977;16:1-132.2. Albrektsson T, Zarb G, Worthington P, Eriksson AR. Thelong-term efficacy of currently used dental implants: a reviewand proposed criteria of success. Int J Oral Maxillofac Im-plants 1986 Summer;1(1):11-25.3. BELOTTI E., PASQUALINI M.E., FANALI S., FLORIS P.L.et al. Guidelines AISI (Italian Academy of Implant Stomato-logy). Registered at the National Medical and Dental Associa-tion. Rome, Italy. Roma. 2001.4. BERTELÉ G., PASQUALINI M.E., BILUCAGLIA L., MI-RANDOLA A Implantologia: dall’ipotesi al carico immediato.European Journal of Implant Prosthodontics 2005 May-Aug;2(1):65-87.5. PASQUALINI U. Le patologie occlusali. Eziopatogenesi eterapia. Milano: Masson; 1993. p. 3-23, 176-86, 338, 414.6. BIANCHI A., SANFILIPPO F., ZAFFE D. Implantologia eimplantoprotesi. Basi biologiche. Biomeccanica. Applicazionicliniche. Torino: UTET; 1999. p. 111-65.7. Consensus AISI (Italian Academy of Implant Stomatology).Dent Cadmos 2004:2;81-83.8. CAPRIOGLIO D., PASQUALINI U. Treatment of dentalagenesis in the child. Av Odontoestomatol 1989May;5(5):299-304, 307-12, 314-15.9. PASQUALINI U., PASQUALINI M.E. Uses and advantagesof the dry self-molding varnish, red indicator, in selective im-pressions. Dent Cadmos 1982 Oct;50(10):49-63.10. MURATORI G. Implant isotopy (II). J Oral Implantol1995;21(1):46-51.11. PASQUALINI M.E, MANGINI F., COLOMBO D., ROSSIF. Stabilizzazione di impianti emergenti a carico immediato.Saldatrice endorale. Dent Cadmos 2001;9:67.12. ROSSI F., PASQUALINI M.E., MANGINI E., MANENTIP. Carico immediato di impianti monofasici nel mascellare su-periore. Dent Cadmos 2005;5:65-69.13. PASQUALINI M.E. Una nuova fresa diamantata a granu-losità differenziata. Il Dentista Moderno 1997 Ott;8:139-142.14. PASQUALINI U. Le patologie occlusali. Eziopatogenesi eterapia. Milano: Masson; 1995. p. 186-92.15. INGRAHAM R., SOCHAT P., HANSING F.J. Curettagegengivale con strumenti rotanti. Una tecnica di preparazionedel dente e del solco gengivale per la presa d’impronta. RivInt Parod Odont Ricostr 1981;1(4):1-33.16. FAVERO G.A. Osteointegrazione clinica: i principi di Brå-nemark. Milano: Masson; 1994. p. 175-192.17. BUCCI SABATTINI V. Tecniche ricostruttive e rigenerati-ve dei mascellari atrofici. I biomateriali: scelta, indicazioni emetodi di uso. Torino: TU.E.OR.; 2007. p. 283-319.

18. BIANCHI A., SANFILIPPO F., ZAFFE D. Implantologia eimplantoprotesi. Basi biologiche. Biomeccanica. Applicazionicliniche. Torino: UTET; 1999. p. 326-31.19. LEGHISSA G., GRAPPIOLO E.G., ASSENZA B. Protocol-li operativi di chirurgia e protesi implantare. Torino: UTET;1993. p. 230-41.20. ABSE P., ZARB G.A, SCHMITT A., LEWIS V.V. Efficacialongitudinale degli impianti osteointegrati, la ricerca di To-ronto: Risposta della mucosa perimplantare. Rivista Interna-zionale di Parodontologia e Odontoiatria Ricostruttiva1991;11(2):317-33.21. TYLMAN S.D., MALONE W.F.P. Protesi fissa. Teoria e pra-tica. Padova: Piccin; 1986. p. 527-96.22. BIAGGI A. Bar of Ackerman or bar CM system with posts.Odont Prat 1974;9(3):201-04.23. DOLDER E. The prosthesis with a bar. Odont Prat1970;5(4):291-97. 24. DOLDER E. Prosthesis with anchorage bar. Rev Fr Odon-tostomatol 1967 Dec;14(10):1658-68. 25. DOLDER E. Bar-joint prosthesis of mandibula. SSOSchweiz Monatsschr Zahnheilkd 1953 Apr;63(4):339-76. 26. Flanagan D. Screwless fixed detachable partial overden-ture treatment for atrophic partial edentulism of the anteriormaxilla. J Oral Implantol 2008;34(4):230-5.27. Nazarian A. Mini dental implants: immediate gratificationfor patient and provider. Dent Today 2005 Oct;24(10):110,112.28. OBWEGESER U. Über eine submucose methode der Al-veolarkamplastik fur Forbereitung der prothesen basis amUnterkiefer und Oberkiefer. Zahnärtzl Praxis 1953;4:21.29. OBWEGESER U. A modification of lingual plastic surge-ry of the alveolar crest according to R. Trauner. SSO SchweizMonatsschr Zahnheilkd 1953 Aug;63(8):788-99.30. OBWEGESER U. Operations tecnik der submukösenMundvorhoplastik in der Unterkiefer. Deutsche Zahnärztli-che Zeitschrift 1956;11:1282.31. BELLINI C.M., ROMEO D., GALBUSERA F., TASCHIE-RI S., RAIMONDI M.T., ZAMPELIS A., FRANCETTI L. Re-habilitation of completely edentulous mandibles. Tilted ver-sus non tilted implant-supported prosthetic designs: a bio-mechanical study. Int J Oral Maxillofac Implants, in press.32.THOMA K. Trattato di chirurgia orale. Pavia: EdizioniCortina; 1959.33. PASQUALINI U. Ampliamento chirurgico dello spaziosottolinguale secondo la tecnica di Lewis ed alcune modifichedella stessa. Riv Ital Stomatol 1962;10:901.34. SCHREINEMAKERS J. Le basi razionali della protesi to-tale. Padova: Piccin; 1986.

Figs. 25-43 are from U. Pasqualini, Le patologie occlusali. Eziopato-genesi e terapia. Milan: Masson, 1993. pp. 401-56.Figs. 45, 58, 62–65 are from Pasqualini, op. cit., pp. 391-92.


TREATISE OF IMPLANT DENTISTRY CHAPTER XIVin collaboration with dr. Silvano U. Tramonte

T he greatest expression of the circulation ofthis implant technique was represented bythe national and international congresses

held by the historic GISI (Gruppo Italiano StudiImplantari, Italian Implant Study Group), foundedand directed by Giordano Muratori. From 1970 to1997 the GISI congresses saw the participation ofthe most distinguished experts, documented bytheir published conference proceedings. The recent conversion of delayed-load implantol-ogy to immediate loading has generated confusionin terms of concepts and definitions. The emergingimplants used for immediate loading by theSwedish school, and identical to those employedfor delayed loading, actually maintained themarked differences between the Swedish and Ital-ian schools, since the immediate loading of the for-mer is based on implants that are completely differ-ent from those employed by the latter. These sub-stantial differences require a separate classificationof the two approaches and identification by thenames of the two schools to which they refer: theItalian school, on the strength of over half a centu-ry of experience, and the Swedish one, which hasyielded to clinical and scientific evidence only re-cently.Despite its belated acknowledgement of immediateloading, the Swedish school managed to producevast literature in a very short time, thanks to itscomprehensive and widespread presence within ac-ademia. Such literature comprises studies on the ILprotocol (1-15), immediate loading with implantswhose design features are still linked to delayedloading. Therefore, we feel it is essential to clarifythe matter with a written protocol that can be usedas a reference for the immediate loading and im-plant techniques of the Italian school. This chapter will thus attempt to remedy for thisshortcoming by briefly outlining the principles and

indications that constitute the protocol and guide-lines of the immediate loading technique of the Ital-ian school.

Definitions Immediate loading is an incontrovertible physio-logical fact that occurs starting with embryonic de-velopment, which constantly applies forces and ex-erts functions on the skeletal apparatus (16).Immediate loading induces two concomitant activ-ities in the peri-implant bone: functional activityand tissue cicatrization. The latter will evolve to-ward a reparative function (osseointegration) whenthere is an adequate load or a defensive one (fi-brointegration) in the presence of an inadequateload. Fibrointegration is one of the two phases ofimplant failure, the other one being mobility, cul-minating with implant loss. It is obvious that thebasic principles and techniques pertaining to im-mediate loading are quite different and sometimescontrast with those employed for delayed loading,which envisions healing of the peri-implant tissuewithout any loading. This partially explains whythe surgical and prosthetic techniques can be per-fectly outlined in a protocol in the case of sub-merged implants, while they can only partially bespecified for emerging implants, whose range of ap-plications is decidedly more complex and subjectsthese implants to a wide range of unplanned andunpredictable situations in delayed-load implanto-logy.By definition, a protocol is a strict operating manu-al that should guarantee the success of the proce-dure, based on case selection and the exclusion ofvariables. This is what makes delayed loading and -to an even greater extent - immediate loading de-rived from the two-step implants harder to manage.Consequently it is difficult to provide a suitable an-swer to the wide range of individual clinical situa-

Introduction

OPERATING PROTOCOL FOR THE IMMEDIATE-LOAD IMPLANTOLOGYOF THE ITALIAN SCHOOL

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185

Operating protocol for the immediate-load implantology of the italian school XIV

tions. The exact opposite can be said of immediateloading with the implants and techniques devisedby the Italian school.The immediate loading used by the Italian schoolfollows a protocol, wherever possible, and suggeststhe guidelines to preserve the full range of applica-tion options of these types of implants and thistechnique.A protocol is a set of standards that regulates the se-quence, preparation and execution of serial proce-dures that can “predictably” lead to a certain result.It is thus a set of strict and self-dependent rules that- from a mechanistic standpoint - influence a pro-cedure, which should be adaptable to the differentclinical situations and able to modulate a highlypersonalized therapeutic answer. To reduce thenumber of variables and keep all conditions undercontrol, the procedure effectively becomes very se-lective, excluding a large number of patients fromtreatment.Inversely, a guideline is a “trail” to be followed wise-ly, one that is full of advice and suggestions. It in-fluences but is not completely binding. In otherwords, it respects the patient’s individuality andspecial needs, leaving the oral surgeon free to makethe most of the situation while also ensuring indis-pensable scientific support and reliable results, anddrawing on previous experience. Therefore, based on these considerations, we willidentify three fundamental steps in immediate-loading rehabilitation according to the Italianschool:1) First or preoperative phase: guidelines and pro-

tocol;2) Second or surgical phase: guidelines and proto-

col;3) Third or postoperative phase: guidelines and

protocol.

First or preoperative phaseGuidelinesDuring the preoperative phase we must obvious-ly be sure to plan carefully, as we would do forany other implant surgery (17-19). The diagnosiswill be based on the classic principles required toachieve both functional and cosmetic rehabilita-tion, where possible, while respecting at least thebasic gnathological principle of a mutually pro-tected occlusion (correct occlusal harmony as de-

fined by Ugo Pasqualini) (20).However, if we are planning a procedure with im-mediate loading, we will need more than this.There are absolute and relative contraindicationsto implant surgery in general and, as usual, theyare equally important. In certain conditions theexecution of immediate loading is more delicateand has a very high risk rate.Aside from all the diagnostic tests that are closelyconnected with the surgery (17-21), we also needadditional data about our patient. We need to ver-ify that the bone metabolism is that of healthybone tissue with a physiological turnover. Forcomplete treatment of this topic, which goes be-yond the scope of this chapter, readers can con-sult specific publications (22). Here we wouldmerely like to point out that it is important to as-sess the normalcy of basic indicators such as:blood sugar, calcemia, phosphatemia, alkalinephosphatase, cholesterolemia, triglyceridemia,hematocrit with leukocyte formula, ESR (erythro-cyte sedimentation rate), blood protein elec-trophoresis, transaminases, calciuria, phospha-turia, urinary hydroxyproline, and for female pa-tients in menopause, also BMD (bone mineraldensitometry). Significant alterations in blood glucose, lipids,transaminases, calcium and phosphorus (bothserum and urinary), phosphatase and hydrox-yproline may indicate the presence of diseasesthat directly or indirectly affect the bone. Thesediseases do not fall within our area of compe-tence, but we nevertheless recommend taking acautious and careful attitude when planning im-plant surgery (23). If there are any pathologies, we can examine thedata and intervene by referring the patient to aspecialist, but nothing can be done when patientsare unwilling to cooperate or are careless. Conse-quently, before placing immediate-load implants,it is advisable to examine their general attitude,psychology, and gender.

Psychodiagnostics11

We can control and sometimes intervene by refer-ring the patient to a specialist for a specific med-ical condition. Likewise, it is advisable to take thesame precautions when dealing with certain psy-chological problems (personality disorders, pho-bias, idiosyncrasies) that affect some patients.These issues are rarely considered so serious as to

1 In collaboration with Franco Merlini, psychotherapist in Milan.

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be classified as frankly psychopathological, butthere is no question that, for the reasons we areabout to examine, inadequate consideration ofthe patient’s “psychology” can affect compliance,especially in the postoperative phase, and it willstrongly influence the patient’s “perceived satis-faction” (24-27). It is important to bear in mindthat the mouth as a whole represents a crucial so-matopsychic crossroads in the evolution ofmankind.During the so-called oral phase, through the rela-tionship with his/her mother’s breast, the new-born comes into contact with the “outside” worldfor the first time, in a veritable melting pot of feel-ings, emotions, perceptions and somatopsychichallucinations that represent the building blocksof mental life. At a later stage of human develop-ment, but also in primates, teeth acquire specialmeaning due to their social function. Teeth are shown to frighten, threaten and attack,but also to meet, learn, approach and seduce. Theloss of teeth, in both dreams and conscious life, isperceived as a loss of vitality, strength, energy,power, charm and relational skills in general. Entering the mouth of a patient and operating onteeth always represents an act of “intimacy” thatthe patient might not be able to accept, despitethe motivations to undergo implant surgery. As aresult, any action involving the oral cavity, even ifminor or minimally invasive, represents - on apsychological level - an event that can trigger pos-sible regressive behavior in the patient, who willthus raise defensive barriers that can significantlyundermine the outcome of the procedure.

Gender1

The patient’s gender determines very different ap-proaches and variable reactions during the vari-ous rehabilitation phases. Women are generally more attentive and compli-ant, and they readily accept postoperative limita-tions and inconvenience. They show up for fol-low-up appointments without complaining, callpromptly to be sure that everything is normal,follow instructions and express any doubts theymay have.Men, instead, tend to be more independent andless willing to consult the physician after the sur-gery. Because of their concept of “oral virility,”their postoperative recovery can be as fast as it isfallacious. Implantations and the placement of temporary

prostheses are perceived as “gratifying” (the use ofteeth as tools, strong chewing, dental aggression,percussion of the teeth, etc.) in order to provethat they are healthy; this is especially true amongmen. Predictably, women are much more con-cerned with the appearance of their smile.

Stress1

This is a very important factor, with no distinctionsbetween men and women. It must be evaluatedcarefully because it will unquestionably producenew parafunctions, repetitive behavior, microtrau-mas, increased sensitivity to pain and so on. Stressleads to hyperactivity of the fixtures and subse-quent overloads. For these types of patients the pre-scription of mouthguards is a good rule of thumb,as is the short-term use of benzodiazepines (whereneeded).

Histrionic personality1

This type of patient is naturally extroverted, essential-ly optimistic, fond of social interaction and always atease in such circumstances, and usually rather self-confident. Far from being an advantage, however, thisactually poses a concealed and less manageable risk.In fact, these patients tend to feel “good” right aftertemporary prosthesis cementation. They tend to con-sider the implant and prosthetic structure as inde-structible (this is particularly true among men) be-cause of the sensation of strength that such devicesimmediately convey (due to the lack of propriocep-tive sensitivity and when there is no irritation).Moreover, these patients tend to:❚ forget to follow instructions, even when they are

given to them in writing; it is essential to drawup an official document, asking the patient tosign a form indicating that they have received theset of instructions and the list of restrictions ou-tlined by the implantologist;

❚ underestimate initial mobility of the temporaryprosthesis, thinking that they can wait until it“moves more” before contacting the specialist;

❚ stop taking prescribed drugs, saying that they fe-el fine; these are patients who do not worry andbelieve that everything will go smoothly, that theprosthesis is very well made and that everyoneelse, included their own doctor, is probably over-ly concerned;

❚ avoid calling, since they believe that what is hap-pening or has already happened is negligible, inspite of the fact that the problem may indeed car-ry some risks.


reactions to the implant, bordering on rejection.Surgery must be planned with the utmost care,respecting of the timing of the patient, whoshould feel in control.

Narcissistic personality1

These patients are not very reliable. They under-estimate or do not properly evaluate the percep-tion of minor irritation that should immediatelyurge them to consult the doctor. Their hyper-trophic ego makes them feel overly self-confident,which often drives them to transgression; they re-fuse to recognize authority and tend to pushthings to the limit, looking for immediate satisfac-tion of their needs. For instance, a patient who has had to refrainfrom fine dining for a long time may be unable toavoid giving in to certain temptations, for no ap-parent reason. Paralleling the behavior of histri-onic patients, those with a narcissistic personali-ty go as far as modifying instructions, changingmedication, stopping treatment or turning to “al-ternative” medicines because, for example, theydo not trust antibiotics. They stop taking the pre-scribed medication because, according to them,they are “dangerous” or unnecessary. Of course,all of this is done without consulting their im-plantologist. This is a patient who needs to dom-inate out of fear of being dominated. Naturally,the indication here is to avoid any form of sym-metrical escalation.

Failure to understand the implications of the implantIn this case, the patient fails to understand and/orremember that an immediately loaded implant isdesigned to perform two concomitant functions,i.e. chewing and osseointegration.

Lack of proprioceptive sensitivityIn completely edentulous patients this lack of sen-sitivity may lead to the exertion of excessive masti-catory force (28).

Parafunctions1

Regardless of how they are caused or implemented,parafunctions represent the greatest danger duringthe first weeks after placement of immediatelyloaded implants. In edentulous patients the habits acquired with re-movable prostheses (parafunctions) remain, andthis may cause overload. The forces applied on the

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The only thing we can do with such patients is to“identify” them, first of all, and then set up morefrequent appointments in order to keep everythingunder control. We can identify the behavior of thistype of patient by examining the occlusal surfacesof the temporary prosthesis, which should be man-ufactured in soft acrylic resin. Typically, these pa-tients should not be given the idea of being “needy”and if they are not treated coldly or aloofly, they arehappy to cooperate with their doctor. Moreover, re-ferring them to the protocol will also help achievethis objective.

Introverted personality1

This type of patient, unlike the preceding one, ispessimistic, reticent and easily depressed. These pa-tients have a hard time understanding the appropri-ate use of their implants. They have many doubtsthat we will never fully understand. They are alsopatients who conceal the truth. The fear of havingruined everything and the ensuing sense of guiltleads the patient to forget or deny certain facts. Weshould maintain a patient, respectful, blameless,sympathetic and attentive attitude. Our chief goal isto gain and maintain the trust of these patients, thetrust they have probably never received from any-one and thus do not expect from their doctor either.It is, however, important to acknowledge their ef-forts in following instructions and show them awillingness to listen.

Hypochondriac personality1

These patients are unwittingly against solvingtheir problem. This opposition can be patholog-ical, and it represents psychological discomfortor aggressive conflict. In their minds, they neverfind the right doctor or definitive treatment. Thepatient-physician relationship is usually doomedto fail because this is the only way that the pa-tient is entitled to continue feeling sick and com-plain about the doctors who took care ofhim/her, then turning to yet other specialists.These patients represent a great diagnostic andtherapeutic challenge, due to the problems thedoctor must face in order to investigate the caseand then the difficulty in identifying the “prob-lem” to be solved. This is by no means a cooper-ative patient, despite his/her full (but only appar-ent) trust in the treatment. There is nothing togain by objecting with him/her and it is insteadadvisable to “share” his/her unshakable skepti-cism. In this type of patient, there can be phobic



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implants will constantly lead to overload and thiswill always occur during lateral movements, sincestress is almost never applied along the main axis ofthe fixture.In totally or partially edentulous patients, there isno way to avoid this. Consequently, prompt place-ment of a mouthguard is advisable (29).

Planning protocol

Number of implants to be placedThe number of implants to be placed depends onmany factors and specific conditions, and as ageneral rule we should try to match the numberof teeth to be replaced. If possible, all implantsshould be placed during the same surgical session(30-32).

Implant sizeIn order to implement immediate loading, it isadvisable to choose (for equivalent cores) a fix-ture with a larger thread diameter, according tothe density and thickness of the bone tissue, andto reach maximum depth, preferably deep bicor-ticalism, respecting the anatomical structures thatare considered to be at risk (mandibular canal,maxillary sinus), in order to maximize the ratiobetween the submerged and emerging struc-tures.2 Any support implant, needles and/or mini-im-plants will be adapted to the existing bone mor-phology.

Insertion axisThe insertion axis should permit placement of thelongest possible implant, respecting the ideal load-ing axis in the case of single-tooth implants or theresultant of the axes for bipods, tripods or multipleimplantations. The lack of parallelism of the coresof endosseous implant fixtures permits greater sta-bility under stress. Finally, the insertion axis shouldmake it possible to achieve bicorticalism whereverpossible (Fig. 1).

Surgical planningIn general, it can be said that implant loadingshould be proportionate to the individual bone’sability to withstand it. This necessarily implies a fi-nal assessment by the surgeon when he/she drills,taps and inserts the implant. Consequently, this isthe time to make final decisions regarding the sizeand morphology of the implant.Each implant must ensure maximum support of thesite chosen for its placement. To accomplish this,several things must be done.1) Implants that can best exploit the dimensional

and morphological characteristics of the boneshould be used: screws that can ensure thebroadest possible contact surface and maxi-mum mechanical interpenetration with thebone, with wide threads and a large screwpitch for cancellous bone, and a narrowerscrew pitch for compact bone; bicorticalscrews to add support for the internal corticalbones, wherever possible; needles for corticalsupport even when dealing with very thinbone or for bipods or tripods joined togetheror connected to screws; blades to achieve max-imum support for lateral loads in very narrowbone. To achieve this and all the followingpoints, the implants should be adaptable tothe various bone morphologies, and should beparallelized by bending and/or drilling at theemerging site right after insertion.

2) Crestal, basal, buccal, palatal or lingual multi-corticalism (the maximum possible cortical sup-port) must be implemented. When this is notfeasible and support relies entirely on the thread,the implant should have wide threads and alarge screw pitch that is inversely proportional tothe type of bone: the lower the bone density, thegreater the width and pitch of the screw.

3) Placement should coincide with the bone’s longaxis, even if this means resorting to a fixture an-

1

2

Fig. 1 Note the broader supportoffered by unparallel implantscompared to parallel ones, and thegreater ability of the former towithstand and dissipate lateral loads.Fig. 2 Bipod formed by a quickscrew and a stabilizing needle.

2 Additional surface treatments (acid-etching, sandblasting,electrochemical treatments, etc.) increase the contact area at thebone/implant interface (33-35).

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gled with respect to the ideal axis of the emerg-ing post.

4) Divergent implants, both in the mesiodistal andbuccopalatal or buccolingual direction, must beinserted in order to broaden the support baseand thus achieve greater primary stability. It isimportant that the axes be divergent, counter-acting each other, and that the resultant be asclose as possible to the ideal loading axis.

5) Bipods and tripods (Fig. 2), implant complexesconsisting of two or three implants, must bemade with endosseous portions that diverge butare joined together at their emergence from thebone. This can be done by means of multipleimplantations in the same site or close unparal-lel insertions, using various types of implants.The more difficult the case, the more useful andadvisable the use of endosseous tripods.

Second or surgical phase

GuidelinesDuring the second phase, i.e. surgery, the mostimportant objective is to achieve the best possibleprimary stability. This is done through extremelycareful placements that are as atraumatic as pos-sible, while trying to perform gradual drilling,without overheating the bone and with a very del-icate insertion. Implant progression should beperformed very carefully, without subjecting thebone tissue to excessive stress.The purpose of each placement is to achieve in-ternal cortical support (bicorticalism) that canguarantee the best immediate primary stability.This represents a crucial moment because as soonas the inner cortical bone is reached, we must im-mediately halt progression to avoid applying ex-tractive forces (“corkscrew” effect) on themedullary bone in contact with the coronal sur-faces of the threads, as this will produce severedamage, causing vascular injury and subsequentischemic necrosis of the bone in between. Only the surgeon’s experience and sensitivity cantell him/her when to halt. Therefore, the proce-dure requires the utmost attention and caution,resisting the temptation of trying to attain greaterstability.Exceeding the limit during the coupling betweenthe tip of implant and the cortical surface will in-evitably lead to lesions and fractures between thebone contained in the threads and the portionthat lies outside them. In the case of single-tooth implants, the protocolrecommends stabilization by means of a second


implant soldered to the first one. The additionalimplant can be normal in size if there is enoughspace (molars), or it can be a needle implant or ascrew with variable diameters if there is less spaceavailable (premolars and incisors) (Fig. 3).

Protocol

Soldered barLet’s assume that surgery ends with soldering ofthe supporting bar. This is a technique recom-mended to achieve immediate loading in thesafest possible way: immediate splinting (30-34)(Fig. 4).It is done with a circular and/or rectangular bar ofGrade 2 titanium, with a diameter ranging from 1 to1.5 mm, placed palatally or lingually with respect tothe fixtures, laid above the mucosa without com-pression, and soldered to each implant by means ofthe intraoral solder. This creates extremely stable,strong and reliable implant splinting (Fig. 5).

Fig. 3 Radiographic checkup ofa bipod 6 years after placement(2001-07). Note the perfectosseointegration.3

Fig. 4 The image shows thesoldered bar below thetemporary prosthesis, whichshould be placed so as to leavea sufficient gap between itsbase and the gum to allowproper hygiene practices during the post-surgical phase.The solder makes the structuremore rigid, allowing eachimplant to dissipate stress and reducing the lever arm due to the presence of thesoldered bar.4

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In the case of isolated implants, atraumatic splint-ing can be obtained using a provisional crownwith retention wings fixed to the adjacent naturalteeth, as long as they are stable.An isolated implant stabilized by a diverging nee-dle is much more reliable and predictable, so thetechnique that exploits a natural supportingstructure should be employed only in those caseswhere the placement of a diverging needle is notfeasible.The use of the intraoral solder (Fig. 6) is indis-pensable. This need is acknowledged by the pro-tocol, as its function is to ensure that the im-plants’ micromovements fall within an acceptablerange and do not jeopardize the final osseointe-gration.Electrowelding, when used by experienced im-plantologists, offers the following advantages:1) it permits implant splinting at the end of the

surgical session, and independently of theplacement of a temporary prosthesis; thismeans that any decementation or fracture ofthe temporary prosthesis will not affect the im-plants, which will still be protected by the sta-ble primary splinting;

2) it creates reliable implant stabilization duringthe osteoclastic phase, which is the most dan-gerous moment for stability due to “grip” lossof the implant surfaces by the bone;

3) it dissipates and distributes the loads more ef-

fectively across the abutments, as well as anypossible overload; even when the professionalis able to provide the temporary prosthesiswith an occlusion free of premature contacts(not always achievable), the patient’s move-ments cannot be controlled and this can leadto unwise or simply unconscious activities;

4) it is the only technique that permits bipods,tripods and unparallel insertions in the samearea, and a single abutment by soldering to-gether the posts of the individual implants;

5) it makes it possible to attain structures withaxial compensation;

6) it can be removed before placement of the fi-nal prosthesis or can be left in place, depend-ing on the postoperative conditions and thedegree of osseointegration.

The soldered bar should be kept in place for noless than 8 weeks, and ideally for 12.Before proceeding with preparation of the finalprosthesis, the bar should be removed to ensureproper evaluation of all implant abutments, butdue also to the frequent need to adapt it to the fi-nal morphology of the soft tissues or the differentrequirements of the definitive prosthesis.Final assessment of osseointegration is crucial:implants must exhibit optimal stability beforeplacement of the definitive prosthesis. Even for implantologists with extensive experi-ence, evaluation of strongly splinted implants, es-pecially when positioned close to each other, issometimes difficult and is directly proportional tothe diameter of the bar employed.Removal of the bar is thus a fundamental step forcorrectly diagnosing possible flaws in the os-seointegration process of every single implant. In-deed, because of the visual obstacle representedby the bar itself, such flaws would remain hiddenbut still dangerously active. In advanced implant surgery on patients whosebone conditions make removal inadvisable, thebar can be maintained or repositioned based onvertical dimensional modifications of the peri-im-plant mucosa. After the soldered bar has been removed, the stateof osseointegration of immediate-load implantswill make them fully comparable to any othertype of implant. In short, the bar no longer servesany purpose, as it has been remarkably replacedby the bone apposition around the implants.Keeping the bar in place when this is not ab-solutely necessary can lead to a less cosmeticprosthesis and reduced control over oral hygiene. Keeping the bar in place offers the following ad-vantages:6

5

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1) protection of the peri-implant tissue: clearly,the presence of the bar allows more efficientdistribution and dissipation of the loads, pro-tecting the mucosa and peri-implant bone andreducing the risk of resorption (34);

2) preservation of the structure: isolated implantsmay be subject to several negative conditions(partial decementation and/or fracture of theprosthesis, occasional or continuous trauma,parafunctions, etc.) that a perfectly splintedstructure can withstand better;

3) an increased number of treatable cases: keep-ing the bar permits treatment of extremely dif-ficult conditions caused by the volumetric ordensitometric scarcity of the available bone.

The disadvantages of keeping the bar in place are:1) cosmetic problems, as the morphological con-

ditions do not always permit perfect or totalconcealment of the bar;

2) an unnatural sensation due to the internal po-sition of the bar (lingual or palatal), particular-ly sensitive patients sometimes find it difficultto accept an unnatural presence that “forces”the tip of the tongue to a constant contact,with effects that can be unpleasant at times;

3) hygienic problems, as perfect cleaning of theinterdental spaces is not always possible;

4) prosthetic problems, which arise not only fromthe complex morphology at the junction be-tween the bar and the abutment, but also thesignificant height reduction due to the pres-ence of the bar, causing retention or cementa-tion problems;

5) clinical visual obstacle, i.e. the presence of thebar makes it very difficult to observe anypathological peri-implant event, delaying diag-nosis because it greatly diminishes signs andsymptoms.

The presence of the bar in the patient’s mouth advitam is thus up to the clinician’s discretion,based on correct assessment of the balance be-tween advantages and disadvantages with respectto the many and sometimes complex variables ofeach case.

Third or postoperative phase

ProtocolThe third or postoperative phase has severalsteps.

Placement of the temporary prosthesisAn acrylic temporary prosthesis will be placed im-mediately in the same surgical session, establishing

a correct vertical dimension and, more importantly,correct occlusion.The temporary prosthesis must be prepared in ad-vance, placed, relined intraorally and properly ce-mented. The use of a reinforced temporary prosthe-sis is advisable to ensure optimum function for aperiod of no less than 2-3 months (23, 30).The temporary prosthesis should respect occlusalprinciples, providing a balanced occlusion both atthe centric relation position and during lateralmovements. Sometimes a provisional crown with palatal or lin-gual retention wings, or with an interproximal-dis-tal concavity (Fig. 7) can be used to support stabi-lization even further, exploiting the adjacent stableteeth in cases with isolated implants.

Application of immediate loading through imme-diate temporary prosthesis Balanced load application allows faster and betterosseointegration.To make a temporary prosthesis with the specificcharacteristics needed for immediate loading, thefollowing principles should be respected.

Assessment of the applicable load:physiological or reduced The load should be proportional to the surface andsupport area of the implant, and to the overall bonequality. Therefore, we can distinguish the load asphysiological when there is good bone quality, andreduced in all other cases. The load will be adjust-ed according to:1) reduction of the occlusal surface by reducing

transverse diameters (Figs. 8-14);2) underocclusion of the crown by reducing oc-

clusal contacts (Fig. 9);3) flat plane occlusion by eliminating occlusal con-

tacts (Fig. 10);

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4) progressive loading, starting from a very reducedocclusion and proceeding by progressive in-creases until correct occlusion has been attained(Fig. 11).

Lateral stress controlWith reference to lateral stress, we must clarify thatin a theoretical stomatognathic model, lateral loadsare nonexistent with the exception of the canine,which is the only tooth physiologically designed towithstand lateral forces (20). A gnathologically cor-rect prosthesis based on this model does not havelateral loads. In a real patient showing parafunc-tions and automatisms (bruxism, etc.), with inter-maxillary relationships that are completely subvert-ed by vertical and centripetal resorption, the appli-cation of lateral forces with significant angles withrespect to the implant and the ideal loading axes isalmost inevitable. The lateral load is always the most dangerous typeof stress when applied to needle or screw implants,especially those with a small core, as this can lead toimplant fracture (25) or mobility. We thus recom-mend careful evaluation of implant position with re-

spect to mobile anatomical structures such as thetongue (19, 20, 36), cheeks and muscle insertions.The size of the tongue should also be taken in dueconsideration. The morphology, position and incli-nation of the antagonist teeth must also be assessed.Stress control can be achieved by means of:1) correct canine disclusion, with a more pro-

nounced slope if necessary, and possible reduc-tion of the cusps of diatoric teeth, down to zero(Fig. 12);

2) reduction of the buccolingual and buccopalatalsurfaces (Fig. 13);

3) reduction of the mesiodistal surface (Fig. 14).

Follow-upThe occlusal check is performed with traditionalmeans: articulating paper and specific detector so-lutions (Red Indicator) (37). The former is verypractical, whereas the latter are more complex touse but very precise. Alternatively, the occlusalcheck can be performed with the aid of more so-phisticated electronic tools (23) such as elec-tromyographers. The percussion sound test should be performed

8 9

10 11

13

1412

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with the temporary prosthesis in place, whichshould be removed in case of doubt for direct ex-amination of the implants. An implant emitting anon-metallic sound should be checked for mobili-ty (possibly by cutting the bar). At this stage, X-raysare not decisive, since radiographic signs are visibleonly later (Fig. 15).

Guidelines

Solutions to possible problemsAssessing the implant’s mobility is very difficult whenthe fixture is soldered to the titanium bar. The percus-sion test remains the most reliable examination.When the implant, tapped at the top and along itsmain axis, produces a non-metallic sound, its stabili-ty should be assessed again upon solder removal. If the implant shows mobility, it should be removedand immediately replaced with another one with alarger diameter, or removed and replaced 30 dayslater with another one with the same diameter, inboth cases after careful surgical curettage. The baris then repositioned and soldered to the implant.If the mobile implant is isolated, it should be re-moved nevertheless and replaced with another onewith a larger diameter, and then immediately stabi-lized by a supporting needle. In the case of isolated implants, this type of doubleplacement should be planned beforehand in orderto avoid unscrewing, a common phenomenon ob-served with single immediate-load implants. Later-al forces can unscrew the implant during the peakof the osteoclastic phase (approximately aroundweek 4-5), when the primary fixation becomesweaker (due to a decrease in bone compression). Figures 16 and 17 show an example of maximumlateral stress: a canine replaced by an immediatelyloaded electrowelded bipodal implant and a gold-

ceramic crown. Isolated implants placed in the lower left and upperright areas are more readily subject to unscrewingduring the postoperative osteoclastic phase, due tothe action of the tongue, which pushes forward vig-orously and applies a torque vector to the lingual-palatal surfaces of temporary crowns. The needle soldered to the single screw counteractsrotation, thus preventing unscrewing.

Physiological and biodynamic principles of immediate loadingAn immediately loaded implant is housed within abone in a very active phase: reparative osteogenesis.The successful process leads to osseointegration,while its failure causes a defense reaction againstthe exogenous noxa: the attempt to expel the im-plant (early mobilization) or encapsulate it (fibroin-tegration). This means that, unlike delayed loading,immediate loading requires rapid action andprompt troubleshooting. It is imperative to act andsolve any problem when the intervention can stillbe considered minimal and no significant bone losshas occurred yet.


15

16

17

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Above all, immediate loading requires a thoroughunderstanding of the phenomenon and its biome-chanical principles, and thus it means learning howto manage it. This is the exact opposite of delayedloading, which involves simply waiting for the bonereparative process to take place.Immediate loading induces and enhances all themechanisms involved in tissue healing by means ofdirect action on the restorative cellular capacity, in-creasing it (38) through the functional activation ofhomeostatic mechanisms, on the basis of the stimu-lus-response principle (39, 40). During the first 20-40 days after surgery, absolute immobility of the im-plant is crucial in order to prevent degeneration of thenewly formed osteoid toward fibrous tissue (41). Thisimmobility can be obtained through two antitheticalprotocols: exclusion of the function according to theSwedish school or functionalization by splinting (42,43) according to the Italian school, which ensuresrigid stability and thus complete immobility of theimplants through constant and perfect splinting ofeach implant (30, 32, 34, 44). The Italian school isstill the only one that - since 1978 - has availed itselfof an extraordinary tool that can ensure reliable andpredictable functionalization by splinting: Mondani’sintraoral solder (45). Currently, the protocol that entails the exclusion offunction is still considered the most advisable dueto its predictability, since it is believed to providegreater protection of the primary stability duringthe crucial postoperative phase. Nevertheless, weshould also note that the studies conducted to datehave not investigated immediate loading with spe-cific implants based on the principles of the Italianschool (Apolloni, Bellavia, Bianchi, Garbaccio,Hruska, Lo Bello, Marini, Mondani, Muratori,Pasqualini, Pierazzini, Tramonte) and of prominentinstitutions such as the GISI, and AISI (AccademiaItaliana di Stomatologia Implantoprotesica) (46).Moreover, the principles of delayed loading, con-sidered “dogma” for far too long, have been appliedto immediate loading only recently, but absurdlyapplying techniques pertaining strictly to delayedloading. The apparent scientific bias of protocols ondelayed loading does not justify disregard for theexisting techniques tested for the Italian school’simmediate loading. In reality, the importance of us-ing implants with large threads and cortical supporthas never been fully recognized (47, 48), let alonethe use of the intraoral solder. Schnitman (49) in1990 and Wohrley (50) in 1992 had alreadydemonstrated that osseointegration can be achievedand maintained with immediate loading. In 2002Bertolai et al. (51) showed that Italian implantswith wide threads and reduced emergent portions

are more effective for immediate loading that thosewith narrow threads and a prosthetic connection.In 1999 Bianchi (18) employed immediate loadingwith temporary immediate splinting (with the sup-porting bar soldered intraorally) and subsequentdefinitive prosthesis (upon removal of the bar) fora very interesting case of immediate loading versusdelayed load (see Chapter 11, pp. 154, 155).Recent studies have acknowledged the effectiveness ofelectrowelding for two-step implants as well (52-56).Histological research has demonstrated the abilityof implants with wide threads and narrow emergentportions to form an adequate epithelial seal (Fig.18) (57), the indispensable prerequisite for optimalbone healing and subsequent osseointegration (18)(Figs. 19-21). The choice of immediate loading is justified byvirtue of an indisputable advantage in achievingmore specific organization of the peri-implantbone, not only with respect to the bone/implant in-terface, but also as the expression of a mor-phostructural adaptation of the entire bone area af-fected by the propagation of functional stimuli (58-63). The regenerative phase of the surgical wound,after implant inclusion and with replacement of thehematoma by the fibrocellular blastema, has signif-icant potential from a qualitative and quantitativestandpoint, due to the ability of the connective ele-ments to differentiate into the distinctive cellularphenotypes of the support tissues. The local meta-bolic status, already enhanced by the induction ofgrowth factors, can be further increased by the di-rect action of the mechanical loads, which also par-ticipate in the phenotypical expression of the undif-ferentiated connective tissue. As far back as 1995,Salama et al. (64) forecast the evolution of the im-plant protocol, from load-free healing to a protocolthat emphasizes and ensures healing with loaded

18

Fig. 18 Close-up of the epithelialattachment on animplant. Note theabsence of keratinicprotection and theprogressive reductionof the cell layers(below), consistingonly of germinal basal cells.

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ducing rehabilitation time by enhancing the bone’sregenerative response according to the theory of thecausal histogenesis of bone tissue (47, 65), notmerely with the aim of bone healing, but also by in-fluencing its formation and orientation, in keepingwith the trajectory patterns suitable for the dissipa-tion of force along the most appropriate directrixes.The studies of Salama (64) (1995), Schnitman (49)(1997) and Tarnow (66) (1997) show that a pros-thesis that can ensure the stability and immobilityof the implants can produce a stable and pre-dictable long-term bone/implant relationship.

Conclusions

Immediate loading is a highly reliable and pre-dictable technique, thanks to the possibilities offeredby the soldering of implants to titanium bars, the useof implants that can be parallelized immediately bybending their necks, the possibility of employing an-gled placement techniques that permit the manufac-ture of any design, making the surgical and prosthet-ic phases more effective, and - lastly - the possibilityof finding a prompt solution to the lack of primaryfixation that can always affect implants, regardlessthe type of technique that is used. In most cases, complications and failures can beavoided through careful and correct diagnosis, andspecific planning. Nevertheless, these complications can easily be over-come with quick, simple and effective solutions.

References

1. CHIAPASCO M., GATTI C., ROSSI E., HAEFLIGER W.,MARKWALDER T.H. Implant-retained mandibular overdentu-res with immediate loading. A retrospective multicenter studyon 226 consecutive cases. Clin Oral Implants Res 1997Feb;8(1):48-57.2. ROSSI E., HAEFLIGER W., CHIAPASCO M. Implant-retai-ned mandibular overdentures with immediate loading: a pro-spective study of ITI implants. Int J Oral Maxillofac Implants2000 May-Jun;15(3):383-8.3. CHOW J., HUI E., LIU J., LI D., WAT P., LI W., YAU Y.K.,LAW H. The Hong Kong Bridge Protocol. Immediate loading ofmandibular Brånemark fixtures using a fixed provisional pro-sthesis: preliminary results. Clin Implant Dent Relat Res.2001;3(3):166-74.4. MISCH C.E., DEGIDI M. Five-year prospective study of im-mediate/early loading of fixed prostheses in completely edentu-lous jaws with a bone quality-based implant system. Clin Im-

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20

Fig. 19 Osseointegration of a Tramonte screw (close-up of athread).Fig. 20 Osseointegration of a Garbaccio screw.Fig. 21 Osseointegration of a Scialom-Mondani needle.

implants, albeit without overloading and preserv-ing primary stability. Stability is obtained with animmediate loading protocol that can yield fully pre-dictable outcomes, due to splinting of the implantsto a titanium bar by intraoral soldering.Immediate loading offers the great advantage of re-

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plant Dent Relat Res 2003;5(1):17-28.5. TESTORI T., DEL FABBRO M., SZMULKER-MONCLER S.,FRANCETTI L., WEINSTEIN R.L. Immediate occlusal loadingof Osseotite implants in the completely edentulous mandible.Int J Oral Maxillofac Implants 2003 Jul-Aug;18(4):544-51.6. DEGIDI M., PIATTELLI A. Immediate functional and non-functional loading of dental implants: a 2- to 60-month follow-up study of 646 titanium implants. J Periodontol 2003Feb;74(2):225-41.7. VAN STEENBERGHE D., MOLLY L., JACOBS R., VANDE-KERCKHOVE B., QUIRYNEN M., NAERT I. The immediate re-habilitation by means of a ready-made final fixed prosthesis inthe edentulous mandible: a 1-year follow-up study on 50 con-secutive patients. Clin Oral Implants Res 2004 Jun;15(3):360-5.8. DEGIDI M., SCARANO A., PIATTELLI M., PERROTTI V.,PIATTELLII A. Bone remodeling in immediately loaded and un-loaded titanium dental implants: a histologic and histomorpho-metric study in humans. J Oral Implantol 2005;31(1):18-24.9. QUINLAN P., NUMMIKOSKI P., SCHENK R., CAGNA D.,MELLONIG J., HIGGINBOTTOM F., LANG K., BUSER D.,COCHRAN D. Immediate and early loading of SLA ITI single-tooth implants: an in vivo study. Int J Oral Maxillofac Implants2005 May-Jun;20(3):360-70.10. ATTAED N.J., ZARB G.A. Immediate and early implant loa-ding protocols: a literature review of clinical studies. J ProsthetDent 2005 Sep;94(3):242-58.11. GLAUSER R., RUHSTALLER P., WINDISCH S., ZEMBICA., LUNDGREN A., GOTTLOW J., HäMMERLE C.H. Imme-diate occlusal loading of Brånemark System TiUnite implantsplaced predominantly in soft bone: 4-year results of a prospec-tive clinical study. Clin Implant Dent Relat Res 2005;7 Suppl1:S52-9.12. BALSHI S.F., WOLFINGER G.J., BALSHI T.J. A prospectivestudy of immediate functional loading, following the teeth in aday protocol: a case series of 55 consecutive edentulous maxil-las. Clin Implant Dent Relat Res 2005;7(1):24-31.13. SEGURA-MORI SARABIA L., DíAZ VIGIL-ESCALERA J.,MAUVEZíN QUEVEDO M., GONZáLEZ GONZáLEZ I. Cargainmediata: situación actual. Immediate loading: current situa-tion. RCOE [periódico na Internet] 2006 Dez; 11(5-6): 529-41. 14. CRESPI R., CAPPARè P, GHERLONE E, ROMANOS G.E.Immediate occlusal loading of implants placed in fresh socketsafter tooth extraction. Int J Oral Maxillofac Implants 2007 Nov-Dec;22(6):955-62.15. DEGIDI M., IEZZI G., SCARANO A., PIATTELLI A. Imme-diately loaded titanium implant with a tissue-stabilizing/main-taining design (“beyond platform switch”) retrieved from manafter 4 weeks: a histological and histomorphometrical evalua-tion. A case report. Clin Oral Implants Res 2008 Mar,19(3):276-82. Epub 2007 Dec 13.16. Enciclopedia Medica Italiana. V. XI. Firenze: Ed. Uses; 1984.p. 2-18.17. SPIEKERMANN H., DONATH K., JOVANOVIC S., RIC-

THER J. Atlante di odontostomatologica: Implantologia. Mila-no: Masson; 1999.18. BIANCHI A., SANFILIPPO F., ZAFFE D. Implantologia eimplantoprotesi. Basi biologiche. Biomeccanica. Applicazionicliniche. Torino: UTET; 1999. 19. MISCH C.E. L’Odontoiatria implantare contemporanea.Parte prima: diagnosi e progettazione del trattamento. Roma:Antonio Delfino editore; 2003.20. PASQUALINI U. Le patologie occlusali. Eziopatogenesi e te-rapia. Milano: Masson; 1993.21. MEZZANOTTE P. Le indagini radiologiche pre e post-im-plantari. Milano: Masson; 2005.22. MORO L., MODRIKY C., BETTICA P. I marcatori biochi-mico-clinici nella fisiopatologia ossea. Milano: Ed. Sorbona,1994.23. TRAMONTE S.U. Prevencion de complicaciones y fracasosen carga inmediata. Rev Espanola Odontoestomatologica de Im-plantes 2005 Dic;13(4):206-16.24. SEMI A. Trattato di psicoanalisi. Vol II. Milano: RaffaelloCortina Editore; 1989.25. GABBARD G.O. Psichiatria psicodinamica. Milano: Raffael-lo Cortina Editore. 26. MC WILLIAMS N. La diagnosi psicoanalitica. Astrolabio;1999.27. BERGERET J. La personalità normale e patologica. Milano:Raffaello Cortina Editore; 1984.28. CHIESA D., CHIAVAROLO P., COLASANTO S., DE CIC-CO V., FERRANTE A. La nuova ortodonzia. Roma: MarrapeseEditore; 2007. p. 11-70.29. FISCHER W.F., O’TOOLE E.T. Personality characteristics ofchronic bruxers. Behav Med 1993 Summer;19(2):82-6. 30. TRAMONTE S.U. La Maxima Expresion de la Carga Inme-diata. I° Congreso Internacional SEI-ICOI. Barcelona. 2002.31. MURATORI G. Implant isotopy (II). J Oral Implantol1995;21(1):46-51.32. ROSSI F., PASQUALINI M.E., MANGINI F., MANENTI P.Carico immediato di impianti monofasici in mascellare superio-re. Dent Cadmos 2005;4:65-9.33. PASQUALINI M.E., MANGINI F., COLOMBO D., MA-NENTI P., ROSSI F. Stabilizzazione di impianti emergenti a ca-rico immediato. Saldatrice endorale. Dent Cadmos 2001;9:67-76. 34. LORENZON G., BIGNARDI C., ZANETTI E.M., PERTU-SIO R. Analisi biomeccanica dei sistemi implantari. Dent Cad-mos 2003;71(10):63-86.35. PASQUALINI M.E. Le fratture da fatica dei metalli da im-pianto. Il Dentista Moderno 1993;(2):31.36. PASQUALINI U., PASQUALINI M.E. Uses and advantagesof the dry self-molding varnish, Red Indicator, in selective im-pressions. Dent Cadmos 1982 Oct;50(10):49-63.37. DAL CARLO L. Influenza della lingua sull’integrazione de-gli impianti endossei. Doctor OS Mag 2003;14(5):479-84.38. ROBERTS W.E. Fundamental principles of bone physiolo-gy, metabolism and loading. In: Naert I., Van Steemberghe D.,Worthington P. (eds). Osseointegration and oral rehabilitation:

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An introductory text-book. London: Quintessence; 1993. p.157-70.39. SCHENK R.K. Biology of fracture repair. In: Browner B.D.,Jupiter J.B., Levine A..M., Traften P.G .(eds). Skeletal trauma.Philadelphia (USA): CV Saunders; 1992. p. 3-19.40. CASTAMAN E. Principi biomeccanici di fissazione. Bolo-gna: Edizioni Aulo Gaggi; 1993.41. ASPENBERG P., GOODMAN S., TOKSVIG-LARSEN S.,RYD L., ALBREKTSSON T. Intermittent micromotion inhibitsbone ingrowth. Titanium implants in rabbits. Acta OrthopScand. 1992 Apr;63(2):141-5.42. LEDERMANN P.D. Kompendium des TPS-Schraubenim-plantates im zahanlosen Unterkiefer. Berlin (Germany): Quin-tessence; 1986.43. BABBUSH C.A., KENT J.N., MISIEK D.J. Titanium plasma-sprayed (TPS) screw implants for the reconstruction of theedentulous mandible. J Oral Maxillofac Surg 1986Apr;44(4):274-82.44. BRUNSKI J.B. Influence of biomechanical factors at the bo-ne-biomaterial interface. The bone-biomaterial interface. Uni-versity of Toronto Press, Toronto (Canada): En Davies JE (ed);1991. p. 391-404.45. MONDANI P.L., MONDANI P.M. The Pierluigi Mondani in-traoral electric solder. Principles of development and explana-tion of the solder using syncrystallization. Riv OdontostomatolImplantoprotesi 1982 Jul-Aug;(4):28-32.46. Consensus AISI (Accademia Italiana di Stomatologia Im-plantoprotesica). Dent Cadmos 2004;2:81-83.47. LEMONS J.E. Considerazioni sui fattori biomeccanici e suibiomateriali degli impianti a forma di radice. In: McNeill C. L’oc-clusione. Basi scientifiche e pratica clinica. Milano: Scienza e tec-nica dentistica; 1997. p. 195-202.48. Vantaggiato G., Iezzi G., Fiera E., Perrotti V., Piattelli A. Hi-stologic and histomorphometric report of three immediatelyloaded screw implants retrieved from man after a three-year loa-ding period. Implant Dent 2008 Jun;17(2):192-9.49. SCHNITMAN P.A., WOHRLE P., RUBENSTEIN J.E. Imme-diate fixed interim prostheses supported by two-stage threadedimplants: methodology and results. J Oral Implantol1990;16(2):96-105.50. BIANCHI A., SAN FILIPPO F., ZAFFE D. Implantologia eimplantoprotesi. Basi biologiche. Biomeccanica. Applicazionecliniche. Torino: UTET; 1999. p. 330-331.51. BERTOLAI R., FERRETTI A., COLLEDAN E. Studio Speri-mentale Clinico “Esperienza clinica nell’implantologia a caricoimmediato” collegato alla tesi di laurea di Colledan E: Impiantia carico immediato AA 2000-2001. Università di Firenze.52. HRUSKA A., CHIAROMONTE BORDINARO A., MARZA-DURI E. Carico immediato postestrattivo. Valutazione clinica su1373 impianti. Dent Cadmos 2003;5: 103-18.53. DEGIDI M., GEHRKE P., SPANEL A., PIATTELLI A. Syn-crystallization: a technique for temporization of immediatelyloaded implants with metal-reinforced acrylic resin restorations.


Clin Implant Dent Relat Res 2006;8(3):123-34.54. DAL CARLO L. La saldatura degli impianti sommersi: oltre12 anni di esperienza clinica. Riv Ital Stomatol 2008;2:34-42.55. FANALI S., VANNINI F. Impianti bifasici solidarizzati consincristallizzatrice endorale. Doctor Os 2007 Nov-Dic;18(9):1047-56.56. DAL CARLO L. Tecnica di protesi fissa su barra saldata nel-le contenzioni definitive. Doctor Os 2004 Giu;15(6):637-45.57. CAMERA A., PASQUALINI M.E., TRAMONTE S.U. Istolo-gia comparata dei tessuti della “zona del colletto” di un dentenaturale e di tre viti di Tramonte. Doctor Os 2005 Nov-Dec(Suppl).58. PASQUALINI U., MANENTI P., PASQUALINI M.E.: Inda-gine istologica su ago emergente fratturato. Impl Orale 1999Aprile;2: 42-5.59. MOGLIONI E., DIOTALLEVI P., PEZZUTI E., FERRANTEG., PASQUALINI M.E., FLORIS P.M. Success rates in subject re-habilitated with immediate loading technique on according toAISI guide lines. Annali di stomatologia 2008; LVI(1-2):19-23.60. PASSI P., MIOTTI A., CARLI P.O., DE MARCHI M. Tramon-te screw for replacement of single teeth. G Stomatol Ortognato-donzia 1989 Apr-Jun;8(2):83-8.61. MANGANO C., PERROTTI V., IEZZI G., SCARANO A.,MANGANO F., PIATTELLI A. Bone response to modified tita-nium surface implants in nonhuman primates (Papio ursinus)and humans: histological evaluation. J Oral Implantol2008;34(1):17-24.62. GRASSI S., PIATTELLI A., FERRARO D.S., FIGUEIREDOL.C., FERES M., IEZZI G., SHIBLI J.A. Histologic evaluation ofhuman bone integration on machined and sandblasted acid-et-ched titanium surfaces in type IV bone. J Oral Implantol2007;33(1):8-12.63. ORSINI G., PIATTELLI M., scarano A., petrone g., kenealyj., Piattelli A., Caputi S. Randomized, controlled histologic andhistomorphometric evalutation of implants with nanometer-scale calcium phosphate added to the dual acid-etched surfacein the human posterior maxilla. J Periodontol 2007Feb;78(2):209-18.64. SALAMA H., ROSE L.F., SALAMA M., BETTS N.J. Imme-diate loading of bilaterally splinted titanium rootform implantsin fixed prosthodontics. A technique reexamined: two case re-ports. Int J Periodont Rest Dent 1995;15:344-61.65. PAUWELS F. Gesammelte abhandlungen zur funktionellenAnatomie des Bewegungapparates. Berlin: Verlag; 1965.66. TARNOW D., EMTYUIAZ S., CLASSI A. Immediate loa-ding of threaded implants at stage 1 surgery in edentulous ar-ches: ten consecutive case reports with 1 to 5 year data. Int LOral Maxillofacial Implants 1997;12:319-24.

Fig. 2 Courtesy of Franco Rossi.Figs. 19 Courtesy of A. Bianchi, F. Sanfilippo, D. Zaffe, from Implan-tologia e implantoprotesi. Basi biologiche. Biomeccanica. Applicazio-ni cliniche. Turin: UTET, 1999, pp. 326–31.

TREATISE OF IMPLANT DENTISTRY CHAPTER XVin collaboration with Paolo Mezzanotte

T oday the diagnostic options for a correctapproach to implants are virtually infinite.Radiology classically divides pre-implant

investigations into first- and second-level exami-nations. For pre-implant planning, the former in-clude orthopantomography (OPG) and intraoralradiographies, the latter specific tomographicimaging (CT). This chapter will deal mainly withtomography, although first-level analyses permit ageneral evaluation of the clinical case.Unlike first-level examinations, where equipmentand software have led to standardized results, forsecond-level examinations and precision tests -when conditions and indications are met - thechoice of one device over another depends on thelevel of accuracy that is needed. Guidelines have been proposed for the optimaluse of technology and as a way to obtain unam-biguous answers to the problems faced by den-tists and maxillofacial surgeons. Nonetheless, itseems useful to examine the motives behind areasonable request for additional second-level ra-diological information, because there is a specificdevice that is preferable for each examination. It is appropriate to examine the reasons that seemto contraindicate CT examinations and explainhow they must be used responsibly:❚ longer time frames;

❚ radiation doses.

Longer time framesThe wide view afforded by panoramic X-rays isan indispensable complement to CT examina-tion. As paradoxical as it may seem, teeth andvoids are better observed through the compre-hensive view offered by the orthopanoramic X-ray than in CT imaging. We seek different an-swers from tomography, which by definition

identifies smaller sectors with a view of details asdiagnostic elements within the three explorabledimensions. At the same time, a template withopaque markers in the areas of interest should al-ways be used so that, following a panoramic X-ray as a preliminary examination, a CT targetingthe area of interest can be performed. The radi-ologist must always take the panoramic X-raywith a template to better target the subsequentCT. Just as the radiologist is willing to accept a longertime frame for performing the first-level investi-gation prior to the CT, so too must the dentist beaware that the preoperative template is a neces-sary aid for accurate surgery, regardless of itspreparation time. Exceptions can be representedby emergencies, e.g. immediate post-extractiveimplantations.

Radiation dosesIt is interesting to note that the absorbed radia-tion varies depending on the equipment that isused.The dentist should be aware that - diagnostic re-sults being equal - some devices have a lower ra-diation emission. He/she must thus recommendthat it is essential to undergo only the prescribedradiographic investigations, explaining this to thepatient. Modern CT equipment (such as the volumetricscanners described ahead) emits very low radia-tion, even if the doses are higher than those emit-ted during orthopantomography.The reasons for conducting a second-level inves-tigation are the following:❚ surgical safety;

❚ more accurate measurements;

❚ legal issues.

Introduction

PRE-IMPLANT RADIOLOGY

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Pre-implant radiology XV

Surgical safetyBy surgical safety we mean a set of objective andsubjective reasons for performing the examina-tions. They can be identified as follows:❚ aesthetic planning, especially for edentulous

patients;❚ questionable OPG images;❚ unforeseen bone mineralization problems;❚ patient perception of the dentist’s professiona-

lism.

Aesthetic planningWe must premise this by saying that CT is the on-ly test that can clarify the three fundamental as-pects for which it is used. The peri-implant as-sessment should, in fact, provide information onthe following anatomical parameters:❚ height;❚ thickness;❚ degree of mineralization.

Even if the OPG is able to provide approximate in-formation on the height of the structures (and, inpart, their mineralization), only the CT scan can al-so assess bone thickness. With this three-dimen-sional view, the dedicated CT examination is theonly analysis that can provide an exact image formodel construction, not only on the articulator butalso for masticatory function, laying the ground-work for correct morphofunctional rehabilitation.The CT examination will thus answer the threequestions we always ask, but it will also providevaluable information on measurements and refer-ence points that would be unattainable otherwise.In short, this is what we refer to as radioguidedimplantology.

Questionable OPG images and unforeseen mineralization problemsThe more we learn about the merits of or-thopanoramic radiography, the more we can un-derstand its limitations.From a spatial standpoint, it seems futile to repeatthat the two-dimensionality of the reference im-ages is an insurmountable limit for the implantol-ogist who would like to know the alveolar thick-ness. This aspect and possible mineralization ar-tifacts are why orthopanoramic X-rays cannot beconsidered a comprehensive diagnostic examina-tion for pre-implant assessment.

Patient perceptionof the dentist’s professionalism What is the basis for the perception of the den-

tist’s professionalism by the patient and amongthe community in general? What is the patient’sopinion when his/her care provider does or doesnot prescribe preliminary examinations beforeimplant surgery? The answer is based in my own experience, as Iam often asked: “Doctor, can you place an im-plant?”The radiologist’s opinion cannot be definitivebased on orthopanoramic X-rays alone. In fact,how can one answer based only on a view of theheight (which, moreover, is not always accurate)?How can one decide without a clear image of themandibular nerve, when there is a sinus close tothe alveolus, when there is an artifact, and so on? Therefore, the radiologist cannot fail to mentionthat a specific tomographic investigation exists,and that it will permit better insight and assess-ment of the clinical case.In this specific case, modern equipment is sohighly specific (volumetric CT) that, consideringthe risk-benefit balance between “therapeutic val-ue and radiation dose”, it is clearly more benefi-cial to undergo to a radiological examination witha low radiation risk than to avoid in-depth diag-nostic studies. It is crucial for the patient to understand the util-ity of in-depth radiological examinations. Fur-thermore, it is advisable to provide him/her witha written note to give the radiologist so that thereport will be aimed at implant planning.

More accurate measurementsInvestigations that provide accurate 1:1 dimen-sional measurements allow the dentist to plancarefully and select the implant with the mostsuitable size and best material.There is no doubt that, without a tomographyand the certainty of accurate measurements ob-tained by a well-executed examination, the cau-tious dentist will opt for smaller implants, thuscreating the “ideological” basis for choosing a ma-terial with less potential for good primary stabili-ty inside the bone: an objectionable choice whenthe actual dimensions involved effectively requirelonger and/or larger implants.

Legal issues

Radiographs should not be taken only for medicole-gal purposes. The medicolegal significance of radi-ographs cannot be ignored (Paolo Mezzanotte).

Having acknowledged the validity of further in-vestigations that engender no real risk of biologi-

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cal damage, the only remaining doubt involvesselecting those that emit lower radiations - whileassuring equivalent diagnostic results - among thespecific equipment now available. The consensusconferences aimed at drawing up guidelines tominimize the margin of discretion, benefiting thesafety of the patient, who is often psychologicallysubmissive or misinformed, introduce the con-cept of informed consent. In this regard, tomog-raphy has acquired probative value in medicalmalpractice cases, and lawsuits can be lost if CTimaging is not included in the clinical protocol.

Radiological protocol

CT imaging is acquired by radiologists whose re-ports will provide the dentist with informationabout measurements and bone status. To arrive atthese results, the specialist relies on a protocolthat strictly follows standardized execution pro-cedures accompanied by accurate preparation ofthe patient through precise indications and, ifpossible, known landmarks in the oral cavity. Theradiologist follows a meticulous process to obtainthe definitive answer, carefully selecting amongvarious options concerning:❚ equipment;

❚ projections;

❚ reference images;

❚ reports.

EquipmentCT imaging employs different technologies,which can basically be split up into two cate-gories: fan-beam scanners (Fig. 1), and cone-beam scanners (Fig. 2). The illustrations show thereciprocal movements between objects and X-raytube in the two main equipment categories.A fan-beam (spiral) CT scanner uses a dedicatedprogram called Denta Scan, which is a softwareapplication for implantology and is loaded intothe equipment, as opposed to the programs de-signed for cone-beam (volumetric) CT scanners,which have the same cognitive purposes but op-erating modes that vary from machine to ma-chine.Figures 3 and 4 show the typical configuration ofa cone-beam CT scanner.

ProjectionsImplant planning relies on a clinical protocol inorder to obtain images with fixed 1:1 magnifica-

1

Fig. 1 Fan-beam technique.

2

Fig. 2 Cone-beam technique.

3

Fig. 3 Cone-beam equipment.

Before image printing, it has to be underscoredthat the examination should always include goodlandmark assessment.

Reference images Images obtained by positioning a template, whichcan vary in shape and material, and indicating theareas of interest on the CT scan are referred to asreference images. Templates are usually manufactured from opaquematerials by the dental technician or dentist. Theyare preferably small in size and cylindrical, in orderto indicate on the radiographs not only the site butpossibly also the bucco-lingual-palatal inclination. Once composed of metal beads (but with limita-tions in radiographic quality and information aboutinclination), today these markers tend to be madefrom less dense materials that are more visible onthe CT scan. They are represented by:❚ gutta-percha and titanium markers;

❚ markers consisting of opaque crowns (barium-loaded resins).

Figures 6-13 show examples of classic markersmade of these materials. In particular, Figures 14and 15 also show the results in 3D sections.

ReportThe report is the result of a careful choice of theappropriate projections needed by the dentist forinformation about thickness, available height andbone mineralization status (when possible), alongwith measurements, angles and significant re-marks.The report thus represents the conclusions of theradiological examination that will be used by thedental specialist. With modern technology, they canalso be copied to a CD or DVD for handy consulta-tion and record keeping.The upper maxilla and the mandible usually showslight differences in the formation of the images,and this is useful for diagnostic purposes.

Upper maxillaThe following illustrations show the sequential im-age elaboration process from the raw data of the ir-radiated area of interest.Note that the CT examination follows the executionof an orthopanoramic X-ray (Fig. 16), possibly tak-en with reference markers.Elaboration of the report generally begins with ascout view (Fig. 17), which is a lateral projection ofthe skull used to choose the most suitable axial ref-erence to locate the sites of interest. The panoramic-like projections (Fig. 19) are cho-

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tion parameters. Consequently, images orthogo-nal to each other and that fulfill these character-istics are preferable. Figure 5 show the basic projections, which aresagittal (the same principle employed forpanoramic-like X-rays, which follow the curvilin-ear profile of the bone), transverse (or cross orparaxial), axial slices, and coronal or frontal slicesused for comparison and for a general overview.The elaboration of these combined projectionsyields the final report.


4

Fig. 4 Cone-beam configuration.

5

Fig. 5 CT projections.

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6

9

13

10

16

11

12

1514

Fig. 6 Opaque markers (beads) on templates. Fig. 7 Barium-loaded resin opaque markers.Fig. 8 Barium-loaded resin opaque markers. Fig. 9 Titanium markers.

Fig. 10 OPG with a gutta-percha marker. Fig. 11 OPG with gutta-percha markers.Fig. 12 Panoramic-like CT image with perforated titanium markers. Fig. 13 OPG with perforated titanium markers.

Fig. 14 3D CT with barium-loaded resin markers. Fig. 15 3D CT with barium-loaded resin markers.Fig. 16 A good starting point: OPG with markers.

7 8

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sen on the axial reference of the upper arch (Fig.18), which are useful to identify the segment need-ed by the dentist. The segment may include one ormore sites or the whole arch.The transverse or cross-sectional projections arethen extracted from the axial reference by means ofdedicated programs such as Denta Scan, which willdetermine the size of the alveoli (Figs. 20, 21).With some programs, the markers can often clearlyoutline the limits of the segment of interest (Fig. 22). The report will thus show the axial reference pro-jection, the panoramic-like images indicating thesegment of interest, the cross-sectional slices withthe measurements of the available height and thick-ness, as well as any other significant informationsuch as the distance between the alveoli and themaxillary sinus. An additional sheet with axial projections will iden-tify any pathological conditions of the maxillary si-nus, which is very useful to know in case of sinuslift procedures.In the event of sinus conditions, assessment of thesequential involvement of the dental elements af-fected by the inflammatory process can also be use-ful. The diagnosis will be formulated on the basis ofthe subsequent bucco-palatal slices through the ex-ecution of sagittal projections. The following images show a report of the upperarch both with the cone-beam technique, which isusually more detailed (Figs. 2-26), and the fan-beam technique (Figs. 27, 28). There are axial, cross-sectional and panoramic-likeslice images, variously combined, and sometimesalso sagittal slices in order to better evaluate theconcomitant sinus disease.

17

18

20 21

Fig. 17 Cone-beam CT: lateral scout view.Fig. 18 Cone-beam CT: axial reference.

Fig. 19 Cone-beam CT: panoramic-like images.

Figs. 20, 21 Cone-beam CT: cross-sectional image extrapolation from axial projection.Fig. 22 Panoramic-like (NewTom program) (above) and axial images of the segment of interest with thecone-beam CT and reference points (red) (below).

19

22

Lower maxilla (mandible)In this case the axial reference of greatest interest,akin to a scout view, is chosen. The mandibularslice with the metal reference markers does not al-ways correspond to the same slice that shows themandibular nerve course, as required by the den-tist. Therefore, using the OPG as a reference (Fig. 29),the two axial references of interest (Fig. 30) extrap-olated from the CT are identified, one with themarkers and the other with the mandibular nerve


2423

25 26

27

28

Figs. 23-25 Cone-beam CT scan report of the upper arch. Fig. 26 Cone-beam CT: set of bucco-palatal sagittal projections to visualize the sinus pathology.

Figs. 27, 28 Fan-beam CT scan report of the upper arch,showing analogous results.

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(Figs. 31, 32). Figure 33 show all the axial references used forelaboration of the cross-sectional images of inter-est. Figure 34 shows the cross-sectional slices of inter-est of Figure 35 in the axial projection, where themeasurements and references for the identificationand direction of the opaque marker, the mandibu-lar nerve, and so on are indicated. Figures 36–38 show the report of the mandible,both with the cone-beam and the fan-beam tech-niques. Unless a clear pathological condition of thejaw is present, the set of axial projections can usu-ally be omitted from the report.It is useful to stress that when a bifid mandibularnerve - of various configurations - is suspected,evaluation of the superficial bone with a 3D projec-tion may be helpful (Figs. 39, 40).

The (already present) future

Within the sphere of CT imaging, we must empha-size that an accurate response is the result of a well-planned examination, which in turn is the fruit ofconstant and specific cooperation between dentistand radiologist. More and more often, the complexity of the clinicalcases requires that the radiological examination gobeyond the bounds of the radiologist’s report toform part of a comprehensive analysis that will cul-minate in a three-dimensional image to be used bythe dentist. The final stereolithographic model (Fig.41), obtained thanks to the standardization ofmethods, can be stored and retrieved in DICOMformat (Digital Imaging and Communications inMedicine). Similarly, the method of applying a reconstructionmodel to raw data is also evolving, making it pos-sible to insert preoperative templates preparedbased on the CT examination. This makes it possi-ble to identify the bucco-lingual-palatal ormesiodistal implant placement directions usingdedicated software, such as the recent SimPlant andBrånemark programs. In this respect the dentist usually takes the place ofthe radiologist, according to his/her own clinicalneeds.Of course, much more remains to be done. In par-ticular, information on bone mineralization status iscurrently done in the form of punctiform record-ings, whereas it would be more useful by homoge-neous areas. The same holds true for the parame-ters pertaining to bone density, expressed asHounsfield units (HU), ranging from negative val-

ues (air = -1000 HU) to very high values (compactbone = +1600 HU), and encompassing a very widerange of values within the Misch classification (4

29

Fig. 29 Reference OPG of the lower arch, with two opaque markers.

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Figs. 31, 32 Cone-beam CT: panoramic-like images andcorresponding axial images.

Fig. 30 OPG: diagramshowing the choice of the two panoramic-likeimages of interest.30

31

32

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classes) or with smaller ranges of the gray scale, al-so derived from highly variable punctiform densityvalues. In conclusion, modern radiology gives dentiststools with a level of safety and precision that wasonce unimaginable. We can rightly state that thecurrent achievements in the field of surgical im-plantology have made by taking giant steps hand inhand with radiology, which follows clinical indica-tions to provide appropriate answers.

35

Figs. 34, 35 Cross-sections of interest in axial projection,showing the measurements and references for the identificationand direction of the opaque marker, and the mandibular nerve.

34

33

Fig. 33 All the axial images included in the segment ofinterest.

36 37 38

Figs. 36-38 Cone-beam CT scan of the lower arch.Analogous fan-beam CT scan report.

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Suggested readings

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41

Fig. 41 Stereolithographic models.

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TREATISE OF IMPLANT DENTISTRY CONCLUSIONS

Endosseous implants are among the great achievements of reconstructive surgery, and thanks tothem the sad situations of edentulism that mortified so many patients until only a few years agoare now disappearing. Unfortunately, in Italy - as elsewhere - far too many people are still una-ble to benefit fully from this technology, due to the paucity of scientific information and inade-quate teaching of this treatment option.Today implantations are offered by almost all dental practices, but these services are often limi-ted to a single method, due to misinformation about the better rehabilitation options offered byother techniques, which are deemed unsuitable because they were experimented in the more di-stant past (albeit with excellent results). A large part of this book is devoted to illustrating - with proven facts - why this attitude is wrongand how much better one could operate if familiar with the great reconstructive possibilities of-fered by bicorticalized emerging implants, intraoral soldering, emerging implants and blades. Ma-ny of the cases presented in the book, detailed regarding the surgical technique, prosthetic solu-tions and follow-ups, could not have been treated with the methods that currently enjoy moreprestige than they deserve, considering their therapeutic potential. Indeed, any failures of the lat-ter methods are attributed to causes that make no reference to planning mistakes, surgical techni-ques or the choice of unsuitable artifacts, yet these are the real culprits.We must add another comment. In Italy and other countries there are renowned professionalswho have successfully been placing thousands of implants considered to be “obsolete.” Why do-n’t research institutes offer these implantologists the chance to teach and divulge their methodsfree of charge? We and a handful of other professionals are the only ones who, for years, havehad the chance to teach on a university level, imparting everything we have deemed useful forenriching our students’ stock of knowledge on implant dentistry. As a result, they can now choo-se the most effective - yet less advertised - techniques on a case-by-case basis.We have no intention of entering into debates that have been avoided so far, but we could detaila long list of dental institutes where only implants of the “latest generation” are adopted, oppo-sing any other type of implant (many of which are better) on the basis of unjustifiable principles.The fact is that we are witnessing the beginning of a new course, because many of those institu-tes are starting to embrace, albeit cautiously, the “old.”

Ugo and Marco E. Pasqualini

Conclusions

dentistry the italian tribute treatise of implant to ... · treatise of implant dentistry 4) (4)....

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