CLINICIAN’S CORNER

Semipermanent replacement of missingmaxillary lateral incisors by mini-implantretained pontics: A follow-up study

Roberto Ciarlantinia and Birte Melsenb

Recanati, Italy, Hannover, Germany, Perth, Western Australia, Australia, and Lexington, Ky

aPrivabDepashule,AustrtuckyThe fiPotenconsuAddreDenmSubm0889-� 201http:/

Agenesis of maxillary lateral incisors can be treated either by closing the space and substituting the canines forthe missing lateral incisors or, in adults, by replacing the missing teeth with fixed prosthetics or implants. Thisarticle illustrates a method that can be used for a semipermanent implant replacement of the missing incisorsin adult patients. An Aarhus mini-implant was inserted perpendicular to the palatal mucosa of the alveolar pro-cess of the edentulous area. A pontic was made at chair side of composite material around a stainless steel wireextending from the mini-implant. This replacement approach allowed for the vertical development of the alveolarprocess and maintained the bone density and morphology of the alveolar process. Five years after placement,periapical radiographs showed that the alveolar process was following the vertical development related to theeruption of the adjacent teeth, and that the morphology and the bone density were maintained, making the laterinsertion of a dental implant possible without additional surgical buildup. (Am J Orthod Dentofacial Orthop2017;151:989-94)

Agenesis of maxillary lateral incisors occurs with avariable prevalence in different ethnic groups.According to Bozga et al,1 the range is 2.2% to

10.1%, whereas most analyses report a prevalence be-tween 6% and 8%. According to a PubMed advancedsearch, the first reports dealing with missing maxillarylateral incisors focused on their prevalence and etiol-ogy.2,3 The treatment options were limited to spaceclosure or fixed prosthodontic bridges involvinginvasive preparation of abutment teeth. With theintroduction of bonding materials and later ofimplants, replacements with less or no preparation ofthe neighboring teeth were possible. The introductionof temporary anchorage devices (TADs) also madespace closure easier, but in some patients the facialprofile indicated that replacement would be the besttreatment. Yet, a problem remained in relation to the

te Practice, Recanati, Italy.rtment of Orthodontics, Klinik f€ur Kieferorthopedie Medizinische Hoch-Hannover, Germany; Department of Orthodontics, University of Western

alia, Perth, Western Australia, Australia; Department of Orthodontics, Ken-University, Lexington, Ky.rst author has completed and submitted the ICMJE Form for Disclosure oftial Conflicts of Interest, and none were reported. The second author is altant for American Orthodontics, which sells the screws.ss correspondence to: Birte Melsen, Holtevej 11, Aarhus C DK-8000,ark; e-mail, birte@melsen.com.itted, May 2016; revised and accepted, December 2016.5406/$36.007 by the American Association of Orthodontists. All rights reserved./dx.doi.org/10.1016/j.ajodo.2016.12.012

ongoing growth-related development of the alveolarprocess.4,5 The effect of the vertical alveolardevelopment was at the beginning underestimated;consequently, the recommended timing for insertion ofpermanent replacements has repeatedly been postponed.

Although several attempts have been made, aconsensus regarding space closure or space maintenancewith later replacement has not been reached.6,7 Anexplanation may be the interaction of many individualfactors such as facial morphology, tooth morphology,lip length, and function, each of which has animportant impact on the decision. Although the trendhas been to recommend space closure, in patientswhere the replacement solution has been chosen, thereis a need for a temporary replacement until maturityhas been reached.

The options frequently described have been a remov-able plate with a tooth replacing the missing tooth and abonded bridge with or without preparation of adjacentteeth. The disadvantage of the removable plate is obvi-ously the required compliance in addition to the contin-uous coverage of the palatal mucosa. In relation to thebonded bridge, occlusal contacts on the adjacent teethmay have a negative influence, hampering the stabilityor making invasive preparation necessary. As an alterna-tive, TADs have recently been suggested as temporary re-placements. This may, on the other hand, lead to anotherproblem because TADs, although not surface prepared as

989

Table. Patients in the study

Patient Sex Age (y)Treatmenttime (mo)

Age atinsertion (y) Right/left/bilateral

1 F 13.2 13 14.3 Right2 F 10.10 30 13.4 Bilateral3 M 11.9 14 13.1 Right4 M 13.3 18 14.9 Left5 F 11.2 24 13.3 Left

F, Female; M, male.

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dental implants, do osseointegrate. A vertically insertedTAD may therefore prevent the surrounding bone fromfollowing the vertical development related to the erup-tion of the adjacent teeth. If, on the other hand, thespace opened for a later implant is left untouched, sig-nificant decreases in both width and height of the alve-olar ridge may occur while waiting for the dentalimplant. Consequently, the necessity is high for a laterbone graft when the implant must be inserted.8,9

The aims of this article were to describe a method fortemporary fixed replacement that allows for the devel-opment of the alveolar process and to report the changesoccurring clinically and radiographically over 5 years.

MATERIAL AND METHODS

Five patients (from 10 years 10 months to 13 years3 months) with agenesis of maxillary lateral incisorsreceived 6 mini-implants that supported temporary re-placements after orthodontic space opening (Table).

An Aarhus mini-implant (Medicon Instrumente, Tut-tlingen, Germany) with a bracket-like head and a highcollar was inserted perpendicular to the alveolar processpalatally in the edentulous area, approximately corre-sponding to the coronal medium third of the length ofthe roots of the adjacent teeth.

The pontic was constructed at chair side on the day ofinsertion of the mini-implant. A 0.0213 0.025-in stain-less steel wire section (American Orthodontics, Sheboy-gan, Wis) was inserted into the slot of themini-implant, and a small loop was bent on the top ofthe alveolar process. The wire was adapted with a dis-tance from the mucosa of 0.5 to 1 mm, with no occlusalinterference and ligated with a tight metal ligature(American Orthodontics).

The loop was configured so that it could generateretention for the composite shaped as a crown. A metalprimer (Kuraray America, New York, NY) was applied tothe wire and dried for 2 to 3 seconds, and then a bondingagent (Adper Scotchbond; 3M ESPE, St. Paul, Minn) wasadded and light-cured for 40 seconds. The crown replac-ing the missing tooth was formed by adding layer afterlayer of composite (Filtek Supreme XT Universal

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Restorative; 3M ESPE) around the extension of thewire, polymerized for 20 seconds each time, startingfrom the gingival side until the buildup of the lateralincisor was accomplished.

To complete the gingival and lateral surfaces of thepontic, the wire with the pontic was loosened from theminiscrew. Then the pontic was refined with fine dia-mond burs and silicon points and checked in the mouthuntil both esthetics and function were acceptable. Oncethe pontic was finished, the wire was ligated tightly tothe bracket-like head of the mini-implant, and the liga-ture was covered with fluid composite (Filtek SupremeXT Flowable Restorative; 3M ESPE) for comfort (Fig 1).Finally, the patients were instructed about flossing dailybetween the pontic and the mucosa.

As retention for the orthodontic tooth movement,performed for the opening of the space for the missinglateral incisor, the canine and the central incisor weresplinted with the adjacent teeth and not with the ponticthat remained separated from the retention.

The 5 patients in this study were monitored every6 months for 5 years. The distance between pontic andmucosa was increased by straightening the wire main-taining the pontic. Intraoral and radiographic imageswere taken immediately after insertion of the mini-implant (Figs 2 and 3) and at the 2-, 3-, and 5-yearfollow-ups (Figs 4 and 5).

RESULTS

The soft tissues adapted well to the pontic over theyears. No inflammation of the soft tissues around thepontic was detected, most likely due to dental flossingin this area. The intermittent pressure exerted to the cen-tral part of the mucosa during function might havecontributed to the generation of papillae between thepontic and the adjacent teeth.

Inflammation of soft tissues around mini-implantsoccurred twice in 1 patient, but it was cured in a fewdays by increasing oral hygiene and by daily chlorhexi-dine mouth rinses.

No bone resorption around the mini-implants wasnoticed; on the contrary, the vertical development ofthe alveolar process followed the eruption of the adja-cent teeth. The loading of the pontic during bitinggenerated a tipping moment to the screw that appearedto be acceptable, since no mini-implants were lost. Theligature wire broke twice in 1 patient and was replacedwith a larger wire. Discoloration of the pontic was notedin 1 patient, most likely caused by strong colors in thediet. Figure 4, C, shows that the composite in the centralarea of the right pontic was replaced to eliminate thediscoloration.

Journal of Orthodontics and Dentofacial Orthopedics

Fig 1. Technique step by step: A, inserting the screw; B, bending the wire. Note that the wire must bebent where it is inserted into the bracket head of the mini-implant because this bend reduces the forcesacting on the ligature; C and D, buildup of the pontic; E, polishing; F, ligating the sectional wire to thescrew.

Fig 2. Postorthodontic treatment intraoral photographs: A and B, patient 1; C and D, patient 2.

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Gingival impingement can occur when the adjacentteeth erupt more than the distance between the ponticand the mucosa; this was seen at visits of 2 patients.Moving the pontic more occlusally by straighteningthe wire connecting the pontic with the mini-implantalleviated this impingement. A small V-bend on thewire when constructing the pontic allowed for theadjustment without removal of the wire from the bracket

American Journal of Orthodontics and Dentofacial Orthoped

head of the mini-implant. Without a bend in the wire al-lowing for adjustment, a new pontic may be necessary.An example of gingival impingement is seen inFigure 4, D, on the right side.

DISCUSSION

In patients with agenesis of maxillary incisors, 1 solu-tion is to open space orthodontically for a later

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Fig 3. Postorthodontic treatment intraoral radiographs: A, patient 1; B and C, patient 2, right and leftsides.

Fig 4. Intraoral images at 5-year follow-up: A and B, patient 1; C and D, patient 2.

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replacement with an implant. However, the maintenanceof this space is not without problems, one being to allowfor the vertical development of the alveolar process whenthe adjacent teeth are erupting, and another to maintainthe width necessary for the planned dental implant.Several studies have demonstrated significant decreasesin the width and height of the alveolar ridge in patientswith congenitally missing maxillary lateral incisors whohad orthodontic treatment to create space for a dentalimplant.8,9 In this clinical report, a method for asemipermanent replacement of a missing maxillarylateral incisor has been described. A TAD placedparallel to the occlusal plane has been suggested. Incontrast to TADs placed perpendicular to the occlusalplane, this position does not prevent the vertical

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development of the alveolar process. The idea wasborn when a TAD that had served as anchorage formesialization of a molar in a patient with agenesis ofall mandibular premolars was unintentionally leftbehind on 1 side in the edentulous area correspondingto the first premolar.10 An additional observation wasmade in a patient with agenesis of both maxillary lateralincisors, where a horizontally placed mini-implant hadserved as anchorage only on 1 side. The hypothesiswas further supported by a dog experiment demon-strating that a horizontally placed TAD could preventalveolar atrophy of an extraction space.10

The mini-implants inserted from the palatal sideserving as support for the pontics were not used asanchorage for tooth movement but were loaded

Journal of Orthodontics and Dentofacial Orthopedics

Fig 5. Intraoral radiographs at the 5-year follow-up:A, patient 1;B andC, patient 2, right and left sides.

Fig 6. Cone-beam computed tomograms at the 5-yearfollow-up: A, patient 1; B, patient 2, left.

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intermittently when the patient occluded on the pontic.It is likely that the strain generated between the mini-implant and the surrounding bone resulted in increasedbone turnover adjacent to the mini-implants. This hy-pothesis was corroborated by the fact that in relationto the bicortical TADs, the clinical examinationconfirmed that the buccolingual width of the alveolarprocess had been preserved during healing.

In 2 patients, 5-year evaluations were performed alsoon CBCT images. The sections made through the ponticarea supported the clinical finding and indicated the bestresults with bicortical screws (Fig 6). The CBCT imagesfacilitated the assessment of the buccolingual dimensionthat determines the appropriate length, position, andinclination of the screw. According to Hourfar et al,11

the first palatal ruga corresponds to 30% to 40% ofthe root length of the central incisors; this referencecould be used to indicate the height where the TADshould be inserted.

The use of TADS placed vertically as a basis for a tran-sitional replacement of a lateral incisorwas previously pro-posed.12-15 The statement byGraham13 that “the insertionof amini-implant in the edentulous space conducts bone-preserving forces during mastication” has however notbeen supported by any evidence. Graham claimed that“alveolar bone height could be preserved as TADs aredifferent fromdental implants anddonot osseointegrate.”Osseointegration is defined as bone-to-implant contact,but although the surface of TADs is smooth and notspecially treated or coated, the bone-to-implant contacthas been described in several animal experiments. TADsexhibit 60% to 80% bone-to-screw contact.16 The os-seointegration will, as in the case of a dental implant, pre-vent the vertical development of the alveolar processrelated to growth; Kokich and Swift17 consequentlywarned against placing TADs on the top of the alveolar

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process. A clinical report published in the same yeardemonstrated inhibition of alveolar growth.14 Wilmeset al,18 on the other hand, stated that they rarely observedalveolar growth inhibition, “probably because of thesmaller dimensions of mini-implants compared to the

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dental implants.” Cope and McFadden12 supported thesame statement when they presented 2 cases in whichthey foundno infraocclusion at the follow-upobservation.However, in 1 case, in the follow-up x-rays, aminor lack ofvertical development of the bone in the area where thescrew was inserted can be noticed.

The discrepancy between those who observe arrestedvertical development and those who do not is explainedby the difference in growth pattern and the short obser-vation period, since the rate of vertical development isboth small and variable.

Mini-implants with a small diameter may, on theother hand, not be able to withstand occlusal forces,and the risk of miniscrew fracture can increase ordecrease according to the diameter of the mini-implants used. Ludwig19 reported recently on 2 patientsin whom there had been fracture of the mini-implantsinserted on the top of the alveolar process; because ofthis complication, he suggested not to use mini-implants inserted vertically.

CONCLUSIONS

A method for a semipermanent replacement of amissing lateral incisor has been described, and mainte-nance over 5 years has been demonstrated. A compositepontic was placed on a stainless steel wire segment ex-tending from a lingually placed TAD with a bracket-like head (Aarhus mini-implant). The bicortically placedTADs were able to preserve or even increase bone densityand morphology of the alveolar process, whereas themaintenance of distance between the pontic and thealveolar mucosa allowed for continuous vertical devel-opment.

ACKNOWLEDGMENT

We thank Alberto Laino for collaboration in the treat-ment of 1 patient.

REFERENCES

1. Bozga A, Stanciu RP, Manuc D. A study of prevalence and distribu-tion of tooth agenesis. J Med Life 2014;7:551-4.

2. Rantanen AV. On the frequency of the missing and pegshapedmaxillary lateral incisor among Finnish students. Am J PhysAnthropol 1956;14:491-6.

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3. Woolf CM. Missing maxillary lateral incisors: a genetic study. Am JHum Genet 1971;23:289-96.

4. Thilander B, Odman J, Jemt T. Single implants in the upperincisor region and their relationship to the adjacent teeth. An8-year follow-up study. Clin Oral Implants Res 1999;10:346-55.

5. Thilander B, Odman J, Lekholm U. Orthodontic aspects of the useof oral implants in adolescents: a 10-year follow-up study. Eur JOrthod 2001;23:715-31.

6. Kokich VO Jr, Kinzer GA, Janakievski J. Congenitally missingmaxillary lateral incisors: restorative replacement [Point/Counterpoint]. Am J Orthod Dentofacial Orthop 2011;139:435-45.

7. Zachrisson BU, RosaM, Toreskog S. Congenitally missingmaxillarylateral incisors: canine substitution [Point/Counterpoint]. Am JOrthod Dentofacial Orthop 2011;139:434-44.

8. Uribe F, Chau V, Padala S, Neace WP, Cutrera A, Nanda R. Alveolarridge width and height changes after orthodontic space opening inpatients congenitally missing maxillary lateral incisors. Eur J Or-thod 2013;35:87-92.

9. Uribe F, Padala S, Allareddy V, Nanda R. Cone-beam computed to-mography evaluation of alveolar ridge width and height changesafter orthodontic space opening in patients with congenitallymissing maxillary lateral incisors. Am J Orthod Dentofacial Orthop2013;144:848-59.

10. Melsen B, Huja SS, Chien HH, Dalstra M. Alveolar bone preserva-tion subsequent to miniscrew implant placement in a caninemodel. Orthod Craniofac Res 2015;18:77-85.

11. Hourfar J, Ludwig B, Bister D, Braun A, Kanavakis G. The mostdistal palatal ruga for placement of orthodontic mini-implants.Eur J Orthod 2015;37:373-8.

12. Cope JB, McFadden D. Temporary replacement of missing maxil-lary lateral incisors with orthodontic miniscrew implants ingrowing patients: rationale, clinical technique, and long-term re-sults. J Orthod 2014;41(Suppl 1):s62-74.

13. Graham JW. Temporary replacement of maxillary lateral incisorswith miniscrews and bonded pontics. J Clin Orthod 2007;41:321-5.

14. Jeong DM, Choi B, Choo H, Kim JH, Chung KR, Kim SH. Novelapplication of the 2-piece orthodontic C-implant for temporarycrown restoration after orthodontic treatment. Am J Orthod Den-tofacial Orthop 2011;140:569-79.

15. Paquette DE. Miniscrew-supported transitional tooth replace-ment: an esthetic alternative. J Clin Orthod 2010;44:321-5.

16. Luzi C, Verna C,Melsen B. The Aarhus anchorage system. Histolog-ical and clinical investigation [thesis]. Aarhus, Denmark: Universityof Aarhus; 2005.

17. Kokich VG, Swift EJ Jr. Temporary restoration of maxillary lateralincisor implant sites. J Esthet Restor Dent 2011;23:136-7.

18. Wilmes B, Nienkemper M, Renger S, Drescher D. Mini-implant-supported temporary pontics. J Clin Orthod 2014;48:422-9.

19. Ludwig B. Proceedings of the 8th International OrthodonticCongress; 2015 Sep 27-30; London, United Kingdom.

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