extractions and orthodontics: primum non nocere · extractions and orthodontics: ... extractions...

DOI: 10.1051/odfen/2014012 J Dentofacial Anom Orthod 2014;17:301� RODF / EDP Sciences

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F O R E W A R D

Extractions and orthodontics:Primum non nocere

Philippe AMAT

Former assistant professor at the University of Paris VPrivate practice in Le Mans

‘‘A tooth is a thousand times more precious than a diamond.’’Spanish proverb

INTRODUCTION

Deciding whether or not to extract per-manent teeth is probably the one aspect oforthodontic practice that has stirred up themost debate. For more than a century, op-posing groups of clinicians have disagreedas to whether it is sometimes necessaryto extract or if it is always possible to de-velop the arches in order to avoid extrac-tions.

Besides a laudable desire to spare ourpatients the trauma and cost of extrac-tions, and the wish to save their perma-nent teeth, the controversy concerns thesupposed consequences of these extrac-tions. Detractors argue that they would be,among other reasons, a contributing factorto the development or worsening ofdysfunctional disorders of the masticatoryapparatus (TMD) or obstructive sleepapnea-hypopnea syndrome (OSAHS), and

of deleterious effects on the esthetics ofthe profile and of the smile.

Must we, as a consequence, abandonthose treatments involving the extractionof permanent teeth?

As it often happens in the medical field,there is no unequivocal answer to this es-sential question; however, the clinicianmust avoid two pitfalls5:

– abandoning all critical judgment, andeven good clinical reasoning, justbecause we have read some dataidentified as evidence-based;

– throw the baby out with the bathwaterand deprive the patient of the signifi-cant contributions provided by a fact-based approach that could improvetreatment.

THE PENDULUM SWINGS BOTH WAYS

Like a scale, the therapeutic indicationfor extractions has swung starting with

Fauchard between two extreme positions:systematically preserving the complete

Address for correspondence:

Philippe Amat8 rue Buffon72000 Le [email protected]

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dentition, regardless of the conse-quences, or blindly resorting to ex-tractions in order to respectcephalometric norms.

We limited this historical review totwo concepts that have particularlymarked our concept of therapy.

At the very beginning of the 20th

century, based on the laws of Rouxand Wolff that had affirmed the pre-dominant influence of functional fac-tors on morphogenesis, E. Angleconcluded that occlusion played thedominant role in functional stimula-tion. Achieving optimal occlusal func-tion was supposed to stimulategrowth of the basal bone and make itpossible to treat arch length discre-pancy without extractions.

Forty years later, once the primacyof control of morphogenesis was at-tributed to genetic factors, C. Tweedrecommended that practitioners re-sort to extractions, in order to adaptthe dentition to the basal bones andto attain the objective of strict reposi-tioning of the incisors.

The evolution of these two thera-peutic concepts has now shiftedmore towards treatment without ex-tractions. Self ligating brackets arethe most recent appliances that pro-ponents, particularly Damon11, claimhave the capacity to significantly re-duce the indications for extractionsas well as the length of treatment.

CRITICAL JUDGMENT AND GOOD CLINICAL REASONING

A few simple observations will al-low us to illustrate how critical it is tobe careful to circumvent one pitfall,that consisting of abandoning our cri-tical judgment and our good clinicalreasoning, as soon as we see datalabeled evidence-based.

One of the questions raised by re-sorting to the extraction of perma-nent teeth has to do with allegationsthat there is a cause and effect rela-tionship between extractions and theappearance or worsening of dysfunc-tional disorders of the masticatory ap-paratus (TMD)26.

If the published data7,16,22 helpedto refute these assertions, the criticalreasoning of the clinician remindshim to be prudent. The authors ofsystematic reviews and of meta-ana-lyses deplore the limitations of thedata, due to the lack of homogeneity

of methodologies used in the studiesand because of the very vague defini-tion of the diagnostic criteria forTMD.

The critical reasoning of the practi-tioner also makes him plan for poten-tial associations of TMD withorthodontics through a epidemiologi-cal filter that reports a significant in-crease in the prevalence of TMDsduring the second decade in the lifeof our patients35.

In addition, and regardless of theconclusions of the published data,the critical reasoning of the practi-tioner forces him to be even morealert to the presence of any previousTMD symptoms or to any factorsthat might trigger these disorders,such as parafunctions. This samegood reasoning will encourage him toaim for the objective of establishing a

PHILIPPE AMAT

2 Philippe Amat. Extractions and orthodontics: Primum non nocere

therapeutic occlusion that meets thecriteria of a functional occlusion.

Before researching the publisheddata for the most significantly effec-tive technique for creating or restor-ing space, good clinical reasoningwould suggest that we at least pre-serve what is naturally available.Highly recommended since 1947 byNance25, the mere preservation of5.15 ± 0.68 mm of space in a mesialdirection is critically important in themanagement of mandibular crowd-ing, as shown by A. A. Gianelly19. Ifwe remain vigilant to the possibilityof the eruption of second molars,whether we ensure this with a lin-gual arch or a lip-bumper, why wouldwe deprive our patients of this ad-vantage?

The early correction of a transverseproblem, and of dysfunctional breath-ing that is associated with it33, canbe recommended. However, all outmaxillo-mandibular expansion, parti-cularly in the presence of a thin peri-odontal biotype, runs the risks ofinducing an orthodontic movement ofthe teeth beyond the bone volumeand, secondarily, inducing gingival re-cessions.

Another element of the debate isthe possible effect of extractions onthe volume of the airway passages:does the reduction of the length ofthe arch after extractions decreasethe available space for the tongueand, consequently, the pharyngealvolume? A retrospective study30 as-sessed and compared tridimensionalpharyngeal modifications in patientstreated, without extractions, or withextractions of four premolars. The vo-lumes of the nasopharynx, of the oro-pharynx and of the area of maximal

pharyngeal constriction were mea-sured by cone beam computed to-mography (CBCT). The resultsshowed no statistically significant dif-ference between the two groups.

The authors concluded that thechoice of treatment, with or withoutextractions, has no effect on thepharynx.

Nonetheless, this study involvedpatients during growth, whose aver-age age at the beginning oftreatment was in the range of12.97 ± 1.15 years for the grouptreated by extractions, and 12.86 ±1.74 years for the control group.

Moreover, for a patient at the endof growth, the good clinical judgmentof the practitioner will make him con-sider it carefully before requiring theextraction of the maxillary premolarsto mask a Class II malocclusion withretruded mandible. If there are riskfactors for (OHAHS), implementingorthognathic surgery to advance themandible, may be preferable to com-pensatory extractions.

Numerous orthodontic publicationssuggest protocols for treatment with-out extractions, that do not take intoconsideration the third molars. It is atruism to recall that the dentition con-sists of 32 teeth. Simple commonsense requires that we plan for thetherapeutic indication for extractionof permanent teeth, while taking intoaccount the possibility of eruption ofthe wisdom teeth20. Rather thansave the premolars, treat crowdingby pushing the teeth beyond thebone volumes, therefore exposingthe patient to an increased risk ofgingival recession, and practicing infine the germectomy of the wisdomteeth, wouldn’t it be better to extract

EXTRACTIONS AND ORTHODONTICS :PRIMUM NON NOCERE

Rev Orthop Dento Faciale 2014;17:301 3

some premolars to correct crowdingand facilitate the development of thethird molars9 (Fig. 1 a to c, Fig. 2 aand b, Fig. 5 a to c, Fig. 6 a and b)?

Good clinical judgment also helpsthe practitioner choose the area be-tween the first or second premolarsas the extraction site. If the manage-ment of the anchorage and takinginto account the facial typology al-lows it, the first premolars are gen-erally preserved. This is because, inparticular, of their greater coronalheight that will ensure a better es-thetic transition from the gingivalcervical line between canines andmolars. We could also choose to

extract them in case of severecrowding involving the risk of canineimpaction, if the patient wishes toshorten the length of treatment(Fig. 1 to c), if their height is similarto that of the second premolarsor for endodontic reasons (Fig. 5 ato c).

Finally, ever since Angle, no thera-peutic method without extractionshas managed to become the stan-dard in any decisive way. This simpleobservation should persuade us toquestion whether we should totallyabandon the therapeutic indicationfor the extraction of permanentteeth.

Figure 1Intraoral buccal views (a) from the right (b) front (c) from the left, taken 6 years after the end of treatment for

a Class II div. 2 malocclusion and ALD, with extraction of the first four premolars.

Figure 2Intraoral occlusal views of the dental arches (a) maxillary and (b) mandible, taken six

years after the end of treatment.

PHILIPPE AMAT


FACT-BASED APPROACH TO OFFSET ANY FALSE SENSE OF CERTAINTY

If it is important to retain one’s cri-tical judgment and good clinical rea-soning, and it is just as crucial toallow the patient to benefit from thecontributions of a fact-based ap-proach that improve treatment.

When the superiority of a treat-ment is demonstrated, it is better ifclinicians use it, with patients, factorsand conditions all being equal6, ofcourse. To not do this might be detri-mental to our patients28: researchdealing with the evaluation of treat-ment results have, many times over,demonstrated that patients who re-ceive treatment grounded in provendata have better results than thosewhose treatment is not21,36.

Being open-minded, is indispensa-ble for the development of scientificknowledge, and must take prece-dence for any therapeutic decision.Our patients have every right to themost effective therapies, whateverthey may be. However, they alsohave every right to be informed ofthe difference between convictionsand scientific facts4. An approachfounded on facts makes it possiblefor the clinician to reconcile open-mindedness, prudence and circum-spection, and therefore avoid gettingbogged down in some delusional pro-selytism.

A fact-based approach allows thepractitioner to increase his indepen-dence vis-a-vis the often partial opi-nions of ‘‘influential power figures’’.Given the fact that an opinion ex-pressed with conviction is more at-tractive than a prudent interpretationof the few available data, someauthors regularly question published

results. A fact-based approach putsat our disposal proven data in orderto respond to their allegations.

We will take two examples of sub-jects of scientific debate that havesignificantly altered and advanced ourinitial beliefs.

The esthetic repercussions ofextractions

We have to admit that a becomingsmile is privileged in society and thatthe quest to esthetically improve theteeth and the face is the main initialmotivation of patients.

Detractors of treatment by the ex-traction of permanent teeth arguethat it causes, among other things, aflattening of the profile, a retrusion ofthe lips, and a reduction in the widthof the smile. Their only substantiationfor their argument is a few isolatedclinical cases and the opinions ofsome authors17,19.

The published data, even if themethodological quality is sometimesuneven, seem to negate these asser-tions:

– do extractions create a profile ora face ‘‘with extractions’’?

A panel of orthodontists and sea-soned dentofacial surgeons were un-able, by simply performing an oralexamination of these patients, to de-termine if they had benefitted from atreatment with or without extrac-tions8 (Fig. 3, Fig. 7 a and b);

To illustrate why this was difficult,we can observe the profile of a pa-tient (Fig. 3) after treatment of hisClass 2 and ALD, with extraction of



Figure 3Profile photo six years after the end of treatment.

The shape of the lips is harmonious and the concavityof the profile is related to the nasal projection and the

protruded chin.

Figure 4Profile of a Greek statue from the 5th century B.C.,

presenting a retruded profile due to the projection ofthe nasal pyramid and the protruding chin.

Figure 5Intraoral buccal photos (a) from the right, (b) front and (c) left, taken 5 years after treatment for a Class 2 malocclu-

sion and ALD, with the extraction of four first premolars. Notice, a minor tooth alignment discrepancy near 25.

Figure 6Intraoral occlusal photos of the dental arches (a) maxillary and (b) mandible,

taken 5 years after the end of treatment.

PHILIPPE AMAT


the four first premolars (Fig. 1a to c,Fig. 2a and b). His profile is retrudedbut the shape of the lips is harmo-nious. The retruded appearance isnot a consequence of the extrac-tions; the retrusion is in relation tothe nasal projection and the protrud-ing chin. The retruded profile wouldstill have been observed evenwithout any treatment, just like theprofile of this Greek statue from theVth century B.C. (Fig. 4) that ob-viously was not involved in any ortho-dontic treatment;

– does the extraction of maxillaryteeth lead to a narrowing of thearches and a widening of thebuccal corridors, that meansalong with the spaces, whensmiling, between the most visi-bly distal buccal faces of theteeth and the labial commis-sures?

Data shows that this has nothingto do with it. Treatments by extrac-tion does not induce any narrowingof the arches or widening of the buc-

cal corridors (Fig. 7c), whereas treat-ments without extractions create aslight expansion of the dental ar-ches1,23;

– can the esthetic attractiveness ofthe smile be affected by theextraction of permanent teeth?

This does not seem to be thecase. If treatment has been per-formed after a complete diagnosticwork-up and meticulous planning,choosing to extract or not does notappear to affect the attractiveness ofthe smile of patients from a frontalview24.

A study of seven characteristics ofthe smile demonstrates the absenceof any deleterious effect from extrac-tion of the four first premolars on theesthetics of the smile18.

The conclusions of these studies,indicating a general absence of ad-verse esthetic effects due to extrac-tions, may surprise the clinician giventhat, for example, there are correla-tions between the retraction of themaxillary incisors, the retractions and

Figure 7Photos (a) frontal, (b) profile and (c) frontal with an exaggerated smile, 5 years after the

end of treatment. The esthetics of the face and of the smile have been preserved.



thickening of the upper lip, and theopening of the nasolabial angle2,32.

This apparent contradiction can beexplained if we notice that thesepublications include patients whosetreatment by extractions was judgedto have been carried out successfully(for example, ‘‘if the treatment hasbeen performed after a complete di-agnostic work-up and meticulousplanning24’’, or whether, ‘‘the deci-sion to extract or not to extract, if itis not based on rigorous diagnosticcriteria, seems to not to have34’’).This seems to exclude, among otherfactors, an excessive cephalometricrepositioning of the mandibular inci-sors (for example: ‘‘if the objective ofattaining a similar position for the in-cisors is respected, patients treatedby extractions or without extrac-tions31’’), and compensatory extrac-tions to mask, in the area ofocclusion, a significant skeletal imbal-ance caused by a Class II with man-dibular retrognathia.

Obviously, the use of extractions isnot synonymous with retrusion ofthe incisors or contraction of the ar-ches. Their effect on the estheticoutcome, whether positive or nega-

tive, depends mainly on the choiceof the extraction sites, the monitoringof the anchorage, the biomechanicalmanagement of the treatment andconsiderations concerning the possi-bility of ending up with an unattrac-tive facial features12.

We would like to illustrate our dis-cussion with the case of a young girlnamed Amelie, 9 year and 8 monthsold, who presented with a dental andskeletal Class II (Fig. 8 a to c, Fig. 9a and b) and labial inclination of themandibular incisors (Fig. 10 a and b,Fig. 11).

We have to choose between threetherapeutic options:

– treatment with the extraction offour premolars, in order to attainthe objective of repositioning thelower incisors. It might probablyresult in an unattractive flatteningof the profile;

– combining orthognathic surgeryto advance the mandible withextraction of the four premolars.This would make it possible tocorrect the labial inclination of themandibular incisors and to opti-mize the esthetics of the profile.

Figure 8Buccal views of the casts before treatment, (a) from the right, (b ) frontal and (c) from the left. The patient

presents a Class 2 malocclusion with ALD.

PHILIPPE AMAT


If there are no stated indicationsof problems with sleep or riskfactors for OHAHS for the pa-tient, we have to consider thecost/benefit-safety risk of thistherapeutic option ;

– treatment without extractionshoping for a favorable mandibulargrowth response, and testing it

Figure 9Occlusal views of the casts before treatment, (a) maxillary and (b) mandibular.

Figure 10Photos (a) frontal and (b) profile before treatment.

Figure 11Cephalometric profile xray taken before treatment.

The patient presents a skeletal Class 2 with mandibu-lar retrognathia and labial inclination of the mandibular

incisors.



with an initial phase of orthopedictreatment.

We decided on this third optionafter presenting the three choices toAmelie and her parents (Fig. 12 a toc, Fig. 13 a and b).

After a treatment phase to alignthe arches using a quad helix and re-taining leeway space with a lingualwire, the maxilo-mandibular growthdifferential was induced during aphase of orthopedic correction byusing a functional and orthopedic de-vice3. An orthodontic phase, was car-ried out with a multi-brackettedsystem and finishing and detailing

was next achieved with an elastofin-isher. Amelie’s growth response totherapy was favorable. This helped topreserve the esthetics of the faceand of the smile (Fig. 14 a to c,Fig. 15), at the cost of a 5� labial incli-nation of the mandibular incisors(Fig. 16).

Are self ligating bracketseffective?

We would like to take the exampleof another debate that has beengoing on recently in orthodonticjournals : are self ligating brackets

Figure 12Intraoral buccal photos taken one year after the end of treatment, (a) from the right, (b) frontal and (c) from

the left.

Figure 13Intraoral occlusal photos of the dental arches taken one year after the end of treatment,

(a) maxillary and (b) mandibular.

PHILIPPE AMAT


Figure 14Photos (a) frontal, (b) profile and (c) three quarters, taken one year after the end of

treatment.

Figure 15Frontal smile photo taken one year after the end of treatment.

Figure 16Profile cephalometric xray taken six months

after the end of treatment.



effective, at the very least, but whenthey are used, do they succeed in re-ducing indications for the extractionof permanent teeth?

In the second part15 of the section‘‘point/counterpoint’’ of the AJODOpublished in January 2013, theauthors evaluated the claims ad-vanced by the proponents of self li-gating brackets as measured againstpublished data. They report that noless than nine random clinical trialsand two comprehensive reviews ofthe literature10,14 all show that theuse of self ligating brackets does notincrease therapeutic effectiveness,with regard to dental alignment or to-tal length of treatment. With typicalBritish humor, they concluded that:‘‘although technological advancesmay seem appealing, osteoclasts

seem to be less impressed than clini-cians.’’

Dwight Damon self ligating brack-ets are among the most popular.Their inventor claims that they havethe capacity to significantly decreaseindications for extractions, pain andlength of treatments. These asser-tions have recently been the objectof a review of the literature37. Theauthors conclude that the use of Da-mon brackets seems to allow for areduction in work time for the ortho-dontist at the chair. On the otherhand, there are no in-depth publisheddata that make it possible to confirmthat their use reduces the pain of thepatient, shortens the length of treat-ment, achieves a more stable or bet-ter result in terms of esthetics orocclusion, or lessens the need fordental extractions.

FACTS AND CONVICTIONS

It must be noted that only a smallnumber of our treatments are basedon uncontestable facts and that allthe published data is far from beingproven and undebatable as much aswe might wish that it were5. There-fore, we have to manage as best aspossible uncertainty. Often, we canonly use as our sole source of infor-mation a few rare studies conductedwith uneven methodological quality.Sometimes even, we can only relyon, using reserve and prudence, ourexperience and/or that of our collea-

gues. This is the whole realm of con-victions that have some scientificlegitimacy, as long as they are pre-sented just as convictions.

The principle of primum non no-cere, ethics13 and common senseand good judgment summon theorthodontist to inform the patient. Anobjective presentation founded on acost-benefit-safety relationship of thevarious options for treatment willhelp the patient, and especially theparents, to make their decision.

THE SPECIAL EDITION – EXTRACTION VERSUS NONEXTRACTION

Now it will have been thirteen yearssince the Dentofacial and Orthodontic

Review dedicated an issue to thetheme of extractions in orthodontics.

PHILIPPE AMAT


This special editions extraction/nonex-traction is the first edition in a series oftwo, whose ambition it is to offer asynthesis of the present debate be-tween the proponents and the detrac-tors of the therapeutic indication forextractions.

Each author, was asked by the edi-torial committee of the Dentofacialand Orthodontic Review to partici-pate in this initial special edition, andto shed light on a particular point ofthis debate.

M. Limme presents the facts thatjustify early interceptive manage-ment, which is actually etiopatho-genic and includes myofunctionalreeducation, as opposed to late treat-ment that may require extractions.

E. Lejoyeux reminds us that theBioprogressive Concept has alwaysrecommended that we try to achievean optimal highly individualized es-thetic and functional outcome, ratherthan one based on standard values.A significant reduction in the use ofextractions, along with the assuranceof stable results, is the consequenceof doing a comprehensive assess-ment of each patient, of choosing totreat early, of neutralizing dysfunc-tions in order to choose the idealshape for the arch and of utilizing re-sources from functional and mechani-cal unlocking with the help of asegmented approach using a multi-bracketed appliance.

J. Cohen-Levy and N. Cohen dis-cuss the current state of knowledgepertaining to post-extraction healingin orthodontics. After a review of themechanisms responsible for healingand the various complications, in the

area of the mucous tissues and thealveolar bone, they present the gen-eral and local factors implicated incases that result in failure to heal.Their article also sets out techniquesfor preserving the alveolus, duringthe surgical procedure, as well asmethods for regenerating tissue.

P. Baron explains the importanceof using mini screw anchorage toshorten the length of treatment,achieve corrections in only onephase, and avoid extraction of premo-lars while maintaining the usual ther-apeutic objectives. He reports themain findings of pilot studies and pre-sents clinical examples, that illustratehis therapeutic approach for crowdingin cases of Class I, II and III.

M. Mujagic details the therapeuticimpact of opting for extraction of alower incisor, as it affects estheticsand occlusion. She lists the advan-tages and disadvantages of extrac-tion. In the second part, she definesthe decision-making criteria that helpto ensure a satisfactory therapeuticoutcome, by eliminating risks foropening gingival embrasures and forthe appearance of an antero-posterioror transverse discrepancy.

The usual sections of the Dentofa-cial and Orthodontic Review create acentral thread, that is both antici-pated and instructive, between thevarious issues.

The heading Clinical Case hosts areport from J. Faure concerning theoptimal treatment management ofmechanical forces when the choiceis extraction. He explains how tomanage space, by therapeutically ne-gotiating between the lack of anterior



and posterior space, to achieve anobjective without sacrificing teeth. Aclinical case illustrates his presenta-tion.

Finally, J. Cohen-Levy shares herRadiological Reflections on Eagle’sSyndrome.

CONCLUSION

Whatever the recognized etiologi-cal factors may be, and irrespectiveof the measures put in place for pre-vention, arch length discrepancy per-sists27, and the choice of a treatmentprotocol remains a delicate therapeu-tic decision.

If Aesop had been an orthodontist,perhaps he would have written thatextractions are neither good nor bad

in and of themselves. They can havea positive or negative effect on theoutcome of treatment, depending onthe pertinence of their indication andthe appropriate biomechanical man-agement of extraction spaces.

We would like to thank ProfessorO. Sorel for the photographs thatappear in Figure 4.

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