Symphyseal distraction in the context of orthodontic treatment: a series of 35 cases.

Ó 2015 CEO Published by / E´dite´ par Elsevier Masson SAS All rights reserved / Tous droits re´serve´s

Original article Article original

Symphyseal distraction in the context of orthodontic treatment: A series of 35 cases Recours a` la distraction symphysaire dans le cadre d’un traitement d’orthodontie : rie de 35 cas a` propos d’une se milie GARREAUac,*, Thomas WOJCIKabc, Hervey RAKOTOMALALAa, E Gwena€el RAOULabcd, Jo€el FERRIabcd a

Departement Universitaire de Chirurgie Maxillofaciale et Stomatologie, mile-Laine, 59037 Lille, France Hôpital Roger-Salengro, CHU de Lille, rue E b Unite INSERM U1008, Medicaments et Biomateriaux a` Liberation Contrôlee, Faculte des Sciences pharmaceutiques et Biologiques, 3, rue du Professeur-Laguesse, 59000 Lille, France c Association Internationale de Medecine Orale et Maxillofaciale, 7bis, rue de la Creativite, 59650 Villeneuve-d’Ascq, France d Universite Lille Nord de France, UDSL, 1, rue Lefevre, 59000 Lille, France Available online: 19 February 2015 / Disponible en ligne : 19 fevrier 2015

Summary

sume Re

Introduction: Use of symphyseal distraction osteogenesis to treat a mandibular bone deficit with tooth-jaw discrepancy due to lack of space makes it possible to avoid the risks associated with the techniques usually envisaged (stripping, labioversion of incisors, extractions). Patients and method: This retrospective study presents the symphyseal distraction technique used in the maxillofacial surgery department of Lille University Hospital between January 1998 and March 2013. Treatment efficacy, complications and the stability of results were all evaluated. Results: Thirty-five patients were included in the study. The gain of inter-mental-foramen space was on average 7 mm (3– 12, standard deviation 1.8 mm). A good occlusal result with dental Class I and no labioversion of the lower incisors was obtained in 27 of the 35 patients (77%). Conclusion: Mandibular distraction by symphyseal osteotomy seems to be a quick, safe treatment for an anterior transversal mandibular deficit giving results that are stable over time. Its

Introduction : Le traitement par distraction symphysaire d’un deficit osseux mandibulaire avec dysharmonie dentomaxil laire par insuffisance de place permet d’eviter les risques des therapeutiques habituellement envisagees (stripping, vestibuloversion incisive, extractions dentaires). Patients et methode : Cette etude retrospective presente la ee dans le service technique de distraction symphysaire realis de chirurgie maxillofaciale du CHU de Lille entre janvier 1998 et mars 2013. L’efficacite de ce traitement, ses complications e evalu ainsi que sa stabilite ont et ees. Resultats : L’etude a inclus 35 patients. Le gain de place e de 7 mm (3–12, interforamen mentonnier moyen a et ecart-type 1,8 mm). Un bon resultat occlusal avec une classe e I dentaire sans vestibuloversion incisive mandibulaire a et obtenu chez 27 des 35 patients (77 %). Conclusion : La distraction osseuse mandibulaire par ^ un traitement de l’insufosteotomie symphysaire apparaıˆt etre fisance transversale mandibulaire anterieure rapide, suˆr et

* Correspondence and reprints / Correspondance et tires a` part : Emilie GARREAU, at: Service de stomatologie et Chirurgie maxillofaciale, Hôpital Salengro, CHRU de Lille, rue Emilie-Laine, 59000 Lille, France. GARREAU) e-mail address / Adresse e-mail : [email protected] (Emilie

International Orthodontics 2015 ; 13 : 81-95 http://dx.doi.org/10.1016/j.ortho.2014.12.003

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milie GARREAU et al. E

Ó 2015 CEO. Published by Elsevier Masson SAS. All rights reserved

stable dans le temps. Sa reussite repose sur une bonne collaboration entre orthodontiste et chirurgien, et sur une selection rigoureuse des patients. Ó 2015 CEO. E´dite´ par Elsevier Masson SAS. Tous droits re´serve´s

Key-words

s Mots-cle

success depends on good collaboration between the orthodontist and the surgeon, and on strict patient selection.

·· ·· ··

Malocclusion/surgery. Mandible/surgery. Osteogenesis. Distraction/methods. oral surgical Procedures/methods. Retrospective studies.

·· ·· ··

Malocclusion/chirurgie. Mandibule/chirurgie. ogene se. Oste thodes. Distraction/me de de chirurgie orale/me thodes. Proce trospectives. Etudes re

Introduction

Introduction

A mandibular bone deficit in the context of tooth-jaw discrepancy caused by lack of space often leads to anterior crowding. The various orthodontic treatments normally envisaged are: coronoplasty or stripping; labioversion of incisors; and extractions (generally of incisors or premolars). In addition, loss of mandibular premolars often leads to extraction of the maxillary premolars for occlusal reasons (unstable molar class III). However, all these treatments, which modify facial harmony, are associated with a significant risk of recurrence [1–3] and a negative impact on the periodontium. Orthodontic mandibular expansion has now been abandoned, since, contrary to what is noted in the upper jaw, intercanine expansion without expansion of the bony base is highly unstable.

ficit osseux mandibulaire dans le cadre d’une dysharUn de monie dentomaxillaire (DDM) par insuffisance de place se rieur. Les traduit souvent par un encombrement dentaire ante rents traitements orthodontiques envisage s habituellediffe ment sont : la coronoplastie ou stripping, une vestibuloversion molaires le incisive, les extractions dentaires (incisives ou pre molaires mandiplus souvent). De plus, les avulsions de pre molaires bulaires entraıˆnent souvent des extractions de pre maxillaires pour des raisons occlusales (classe 3 molaire rapeutiques, en portant atteinte instable). Or, ces the quilibre de la face, ont un risque de re cidive non a` l’e gligeable [1–3] ainsi que des conse quences ne fastes sur ne le parodonte. L’expansion mandibulaire orthodontique est e : en effet, l’expansion quant a` elle aujourd’hui abandonne intercanine sans expansion des bases osseuses est, contrairement au maxillaire, fortement instable. rapeutique La distraction symphysaire est une alternative the crivit dans les qui ne comporte pas ces risques. Ilizarov de es 1960 les principes de la distraction osseuse [4] ; et anne s au massif facial de s 1992 celle-ci fut introduite avec succe par Mac Carthy et al. [5,6] dans le traitement de dysplasies re craniofaciales dans le sens sagittal et vertical. La premie s oste otomie symphysaire me diane distraction osseuse apre crite par Guerrero en 1997 [7]. Cette technique base e fut de oformation osseuse entre les surfaces de deux sur une « ne pare s par une traction segments osseux graduellement se croissante » [8] permet d’augmenter la longueur d’arcade mandibulaire et la distance intercanine. Ainsi, l’orthodontiste der a` l’alignement dentaire sans recours a` une peut alors proce vestibuloversion compensatrice. Le parodonte ainsi que le serve s. capital dentaire sont ainsi pre re e Cependant, la distraction symphysaire, souvent conside e, reste un traitement tre s rarement comme invasive et risque par les orthodontistes. propose tude a e te : Le but de cette e

Symphyseal distraction is an alternative treatment that does not involve the same risks. Ilirarov described the principles of bone distraction back in the 1960’s [4], and it was successfully applied to the facial structures by McCarthy et al. [5,6] in 1992 for the treatment of sagittal and vertical craniofacial dysplasia. The first bone distraction after median symphyseal osteotomy was described by Guerrero in 1997 [7]. This technique, based on “osteogenesis between the surfaces of two bone segments progressively separated by increasing traction” [8], makes it possible to widen the mandibular arch and the intercanine distance. The orthodontist can then align the teeth without any compensatory labioversion of the incisors. The periodontum and tooth capital are thus preserved. However, symphyseal distraction is often considered invasive and risky, and is rarely proposed by orthodontists. The aim of this study was to:

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International Orthodontics 2015 ; 13 : 81-95

Symphyseal distraction in the context of orthodontic treatment: A series of 35 cases

rie de 35 cas Recours a` la distraction symphysaire dans le cadre d’un traitement d’orthodontie : a` propos d’une se

— evaluate efficacy, complications and stability.

senter la technique de distraction symphysaire — de pre e dans le service de chirurgie maxillofaciale de Lille propose depuis 1998 [9] ; valuer l’efficacite , les complications et la stabilite . — d’en e

Patients and method

thode Patients et me

Patients

Patients

This retrospective study concerned the patients treated by symphyseal distraction in the Stomatology and Maxillofacial Surgery department of Lille University Hospital between January 1998 and March 2013. Inclusion criteria were as follows: — diagnosis, established clinically and on dental impressions (fig. 1), of mandibular tooth-jaw discrepancy due to a space deficit greater than 3 mm; — treatment by distraction osteogenesis after median symphyseal osteotomy; Exclusion criteria were as follows: — previous mandibular dentoalveolar distractions (i.e. without osteotomy of the symphyseal bone base); — bilateral parasymphyseal bone distractions.

tude re trospective a concerne les patients traite s par Cette e distraction symphysaire dans le service de stomatologie et chirurgie maxillofaciale du CHRU de Lille entre janvier 1998 et mars 2013. res d’inclusion e taient : Les crite — un diagnostic de DDM mandibulaire par insuffisance de rieure a` 3 mm e tabli cliniquement et sur les place supe empreintes dentaires (fig. 1) ; alise par distraction osseuse apre s — un traitement re otomie symphysaire me diane. oste res d’exclusion e taient : Les crite olodentaires mandibulaires ante rieures — les distractions alve otomie de base osseuse symphysaire) ; (c’est-a`-dire sans oste rales. — les distractions osseuses parasymphysaires bilate

Pretreatment data collected

es pre the rapeutiques recueillies Donne

Information on the sex, age and comorbidities of patients was collected during a multidisciplinary consultation with orthodontists and maxillofacial surgeons. The orodental situation, the Angle classification and any possible temporomandibular pathology were evaluated by clinical examination. Dental impressions were used to examine precisely the occlusion, tooth crowding, arch width and jaw-tooth discrepancy. X-ray examinations comprised a panorex and lateral and front-view headfilms. Facial morphology was studied using front-view and profile photographs.

Au cours d’une consultation pluridisciplinaire orthodontique et ^ge et les maxillofaciale, un interrogatoire recueillait le genre, l’a s. Un examen clinique pre cisait l’e tat buccodencomorbidite taire, la classe dentaire (selon la classification d’Angle), et une ventuelle symptomatologie temporomandibulaire. L’e tude e ciser l’articule dentaire, des empreintes dentaires aidait a` pre l’encombrement dentaire, la longueur d’arcade et la DDM. Le bilan radiographique comportait un orthopantomogramme et le radiographies de cra ^ ne de profil et de face. Une e tude des te tait re alise e a` partir de photograde la morphologie faciale e phie de face et de profil. taient alors Le motif de distraction ainsi que le gain attendu e cise s. pre

— present the symphyseal distraction technique used in the Maxillofacial Surgery Department in Lille since 1998 [9];

The reason for the distraction and the expected gain were then specified.

[(Fig._1)TD$IG]

Fig. 1: a and b: 2 patients with mandibular tooth-jaw discrepancy. sentant une DDM mandibulaire. Fig. 1 : a et b : 2 patients pre


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Organization of treatment

Mise en place du traitement

Preoperative orthodontic treatment

ope ratoire Traitement orthodontique pre

Preoperative orthodontic treatment has two functions: — make the surgical procedure safer by increasing the space or divergence between the two roots where the osteotomy is planned; — unblock the lower jaw, using various means depending on the initial situation: posterior bite turbos, retroincisal bite plane, maxillary expansion (quadhelix, expander), correction of incisal linguoversion.

ope ratoire a deux fonctions : Le traitement orthodontique pre curiser le geste chirurgical en augmentant l’espace ou la — se divergence entre les deux racines entre lesquelles le trait otomie e tait envisage ; d’oste verrouiller le maxillaire, par diffe rents moyens en fonc— de rieures, plan re trotion de la situation initiale : cales poste incisif, expansion maxillaire (quadhelix, disjoncteur), correction d’un palatoversion incisive.

Surgical technique

Technique chirurgicale

The osteotomy and installation of the distraction device were performed under general anesthesia with a short hospital stay.

otomie et la mise en place du dispositif de distraction L’oste taient re alise es sous anesthe sie ge ne rale au cours d’une e courte hospitalisation. tait une incision muqueuse labiale infe rieure, La voie d’abord e a` distance du fond vestibulaire, de canine a` canine (fig. 2). Une rioste e de Xylocaı¨ne adre naline e 1 % e tait infiltration sous-pe alise e. Le muscle orbiculaire et le pe rioste e taient alors re s. La partie ante rieure de la symphyse e tait ensuite incise e avec repe rage des foramens mentonniers. Ce expose collement sous-pe rioste respectait la basilaire, hormis sous de diane de la symphyse pour permettre l’oste otomie la ligne me et sous les foramens mentonniers pour introduire une lame able de chaque co ^te prote geant les nerfs V3. La ligne malle diane symphysaire e tait repe re e et marque e a` la fraise me ro 4 sur la corticale ante rieure. Apre s conformaboule nume osynthe se sur la symphyse, le dispotion des plaques d’oste tait fixe a` l’aide de vis monocorticales en sitif de distraction e respectant les apex dentaires. La conformation des plaques ^tre pre cise pour que la synthe se se fasse sans aucune devait e s de pose du mate riel, l’oste otomie symphycontrainte. Apre tait re alise e a` la scie oscillante de la basilaire saire bicorticale e otomie e tait ensuite jusque sous les apex dentaires. L’oste

The surgical approach was by way of an incision in the lower labial mucosa, at some distance from the labial sulcus, from canine to canine (fig. 2). A sub-periostal infiltration of Xylocaine with 1% adrenaline was performed. The incision was then continued through the orbicular muscle and the periosteum. The anterior part of the symphysis was exposed and the mental foramens were marked. The sub-periostal cleavage spared the basilar part except under the midline of the symphysis where the osteotomy would be performed and under the mental foramens where a flexible osteotome would be introduced on each side to protect the V3 nerves. The midline of the symphysis was identified and marked on the anterior cortical surface using a number 4 round bur. After positioning of the osteosynthesis plates on the symphysis, the distraction device was attached using monocortical screws and carefully avoiding the apices of the teeth. Plate positioning needed to be precise to ensure stress-free osteosynthesis. After removal of the equipment, bicortical symphyseal osteotomy was performed from the basilar level to just under the

[(Fig._2)TD$IG]

Fig. 2: Canine to canine incision in the labial mucosa. Fig. 2 : Incision muqueuse labiale de canine a` canine.

84




[(Fig._3)TD$IG]

Fig. 3: Interradicular alveolar osteotomy with fine osteotome. otomie alve olaire interradiculaire a` l’oste otome fin. Fig. 3 : Oste

te e soit a` l’oste otome fin (fig. 3) soit a` la fraise boule comple ro 4 entre les apex dentaires. Le distracteur e tait refixe , nume sur les trous de ja` re alise s. Puis une activation test du centre tait re alise e pour ve rifier la mobilite des deux distracteur e tait ferme en un plan fragments osseux. L’abord labial e sorbable. muqueux au fil re

apices, using a reciprocating saw. Osteotomy was then continued between the root tips either with a fine osteotome (fig. 3) or with a number 4 round bur. The distractor was re-attached, centered on the holes already drilled. The distractor was activated to check the mobility of the two bone fragments. The labial incision was closed using absorbable sutures in the mucosal plane. Two types of bone-mounted distractor were used consecutively: one with an intra-tissue screw and the other with an extra-tissue screw (figs. 4 and 5).

te utilise s Deux types de distracteurs a` ancrage osseux ont e cutivement : un distracteur a` ve rin intratissulaire et un conse rin extratissulaire (fig. 4 et 5). autre a` ve

Postoperative management

ratoire Prise en charge postope

An electric chin-strap was left in place for 5 days. Postoperative care comprised an oral antibiotic (amoxicillin and clavulanic acid), a level-1 pain-killer, and the usual mouth-wash for 8 days. Blended food was prescribed for 2 months after distraction.

re e lastique e tait laisse e en place 5 jours. Les Une mentonnie ratoires associaient une antibiothe rapie orale soins postope (amoxicilline et acide clavulanique), un antalgique de palier 1 et des bains de bouche classiques durant 8 jours. e e tait poursuivie jusqu’a` deux mois Une alimentation mixe s la fin de la distraction. apre

[(Fig._4)TD$IG]

Fig. 4: Distractor with intra-tissue screw. rin intratissulaire. Fig. 4 : Distracteur a` ve


85


[(Fig._5)TD$IG]

Fig. 5: Distractor with extra-tissue screw. rin extratissulaire. Fig. 5 : Distracteur a` ve

Distraction phase

Phase de distraction

After a waiting period of 8 to 10 days, the patients were seen again by the surgeon for a postoperative consultation during which activation of the distractor was begun. Daily activation of the distractor was then performed by the patient. The rate of distraction varied between 0.25 mm and 2 mm per day depending on patient tolerance and the increase required. The rate was modified weekly by the orthodontist.

s une pe riode de latence de 8 a` 10 jours, les patients Apre taient revus par le chirurgien en consultation postope ratoire e tait initie e. La distraction e tait au cours de laquelle l’activation e alise e par le patient. ensuite quotidiennement re La vitesse de distraction allait de 0,25 mm a` 2 mm/jour en rance du patient et du gain souhaite . fonction de la tole tait faite par L’adaptation hebdomadaire de cette vitesse e l’orthodontiste. tait poursuivie jusqu’a` l’atteinte du gain de La distraction e par l’orthodontiste. (fig. 6) Le dispositif de displace souhaite tait ensuite maintenu en place pendant une pe riode traction e s la fin de la distraction. Apre s d’au moins deux mois apre rification de la consolidation osseuse cliniquement ve ) et radiologiquement, le (absence de douleur et de mobilite

Distraction continued until the space gain determined by the orthodontist had been achieved (fig. 6). The distraction device was then left in place for at least 2 months after the end of distraction. After clinical verification of consolidation of the bone (no pain or mobility) and X-ray control, the extra-tissue device was removed under local anesthesia (removal of the

[(Fig._6)TD$IG]

Fig. 6: Verification by the orthodontist of the mandibular arch space gain. Fig. 6 : Surveillance par l’orthodontiste du gain de place sur l’arcade mandibulaire.

86




[(Fig._7)TD$IG]

Fig. 7: Osteosynthesis material left in situ after distraction (ablation of the screw and cutting of transgingival attachment arms). riel d’oste osynthe se laisse en place apre s la distracFig. 7 : Mate rin et section des barres d’attaches tion (ablation du ve transgingivales).

jack-screw and cutting of the transgingival attachments). The osteosynthesis appliance was left in place (fig. 7). Its removal could be proposed if it caused discomfort. This could be done either under a local anesthetic plus sedation, or under general anesthesia if this is required for another procedure (e.g. secondary orthagnathic surgery, extraction of wisdom teeth or genioplasty).

tait retire sous anesthe sie locale dispositif extratissulaire e rin et section des barres d’attaches transgingi(ablation du ve riel d’oste osynthe se e tait ensuite laisse en vales). Le mate ^tre propose e place (fig. 7). L’ablation de ce dernier pouvait e ^ne a` ce niveau. Cette ablation a` un patient ressentant une ge riel pouvait alors e ^tre re alise e soit sous anesthe sie de mate te e par une se dation, soit lors d’une anesthe sie locale comple ne rale pour un geste autre (chirurgie orthognathique secge nioplastie par ondaire, avulsion des dents de sagesse, ou ge exemple).

Postdistraction orthodontic treatment

Traitement orthodontique postdistraction

Orthodontic activation was generally begun 2 weeks after the end of distraction. The aim was then to level and align the anterior segment while maintaining a 90 i/m angle. At the end of the orthodontic treatment, a fixed retention was installed in the form of a lingual retention wire from canine to canine. This remained in place at least 1 year to ensure that good-quality bone was obtained.

tait de bute e en re gle ge ne rale L’activation orthodontique e s la fin de la distraction. L’alignement et deux semaines apre rieur e taient alors recherche s tout le nivellement dentaire ante servant un axe i/m de 90 . en pre

Clinical and paraclinical follow-up

Suivi clinique et paraclinique

During the distraction phase, the orthodontist performed weekly monitoring of the tolerance of treatment and its efficacy as judged by the clinically-visible space gain. During the postdistraction orthodontic phase, checks were programed every 2 months. Panoramic X-rays were regularly performed to look for the formation of callus and check the absence of root resorption. Efficacy was evaluated by: — the gain in distance between the mental foramens on A/P cephalometric radiography at the end of distraction (fig. 8);

Lors de la phase de distraction, la surveillance s’effectue de rance du traifa¸con hebdomadaire par l’orthodontiste : la tole juge e sur le gain de place tement ainsi que son efficacite ^ le es. Lors de la phase orthovisible cliniquement sont contro dontique postdistraction, cette surveillance est bimensuelle. ^ les re guliers par panoramique dentaire recherchDes contro eront l’apparition d’un cal osseux et l’absence de rhizalyse. e tait appre cie e par : L’efficacite — le gain de distance entre les foramens mentonniers sur la le radiographie de face a` la fin de la distraction (fig. 8) ; te


` la fin du traitement orthodontique, une contention fixe e tait A mise en place : un fil de contention linguale de canine a` canine lai ne cessaire maintenu au minimum 1 an pour atteindre le de . a` l’obtention d’un os de qualite

87


[(Fig._8)TD$IG]

Fig. 8: a, b: Gain in distance between the mental foramens measured on the A/P (ante et post distraction) cephalogram at the end of distraction. s sur les Fig. 8 : a, b : Gain de distance entre les foramens mentonniers mesure le radiographies A/P (ante et post distraction) a` la fin de la distraction. te

— the occlusal result at the end of the active phase of orthodontic treatment. Consolidation of the bone was evaluated by absence of pain and of bone mobility. Occlusal stability was evaluated clinically and radiologically 6 months after the end of the active orthodontic phase.

sultat occlusal en fin de phase active du traitement — le re orthodontique. tait juge e sur l’absence de douleur La consolidation osseuse e osseuse. et de mobilite occlusale e tait e value e cliniquement et radiologiLa stabilite quement a` 6 mois de la fin de la phase active orthodontique.

Results

sultats Re

Description of the population

Description de la population

Between January 2008 and March 2013, 35 patients were treated by distraction osteosynthesis with medial symphyseal osteotomy in the Stomatology and Maxillofacial department in Lille. Eighteen of these patients were female, 17 male. Average age was 21 (13–47). Almost all these patients (34) were dental Class II. As for the skeletal situation, 28 patients also had a Class II dysmorphosis according to Delaire’s analysis, and just one patent was a dentoskeletal Class III.

te traite s par Entre janvier 2008 et mars 2013, 35 patients ont e otomie symphysaire me diane distraction osseuse avec oste dans le service de stomatologie et chirurgie maxillofaciale taient des femmes et 17 de Lille. Dix-huit de ces patients e ^ge moyen e tait de 21 ans (13–47). des hommes. L’a de ces patients (34) pre sentaient une classe La quasi-totalite II dentaire. Concernant la dysmorphose squelettique, et selon sentaient e galement une l’analyse de Delaire, 28 patients pre tait dysmorphose squelettique de classe II ; un seul patient e en Classe III dentosquelettique. sentait une dysplasie dento-osseuse. Deux Une patiente pre sentaient un syndrome malformatif (syndrome de patients pre Franceschetti, fente faciale 5 de Tessier).

One patient presented with osteodental dysplasia. Two patients suffered from malformations (Franceschetti-Klein syndrome, Tessier No. 5 facial cleft).

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[(Fig._9)TD$IG]

Fig. 9: a and b: patients with agenesis of the lateral incisors, pre- and postdistraction; c and d: patients with agenesis of 42, pre- and postdistraction. sentant une age ne sie des incisives late rales en pre - et postFig. 9 : a et b : patients pre sentant une age ne sie de la 42 en pre - et postdistraction. distraction ; c et d : patients pre

Twelve patients presented with bimaxillary endognathia, including one patient who initially consulted because of a severe obstructive sleep apnea-hypopnea syndrome. Brodie’s syndrome was diagnosed in two patients.

tait Une dysfonction des articulations temporomandibulaires e e chez 2 patients. retrouve tait pre sente Motif de distraction : une DDM mandibulaire e s. Chez 6 patients, cette DDM chez tous les patients traite cidivait apre s un traitement orthodontique comportant des re molaires mandibulaires. Deux patients extractions de pre sentaient des age ne sies des incisives mandibulaires pre (fig. 9). sentaient une biendomaxillie dont un Douze patients pre tait un syndrome patient dont le motif de consultation initial e es hypopne es obstructives du sommeil se ve re. Un synd’apne te diagnostique chez 2 patients. drome de Brodie a e

Operative phase

ratoire Phase ope

An intra-tissue distractor screw was used in 7 cases; the other 28 patients were equipped with an extra-tissue distractor screw. In two patients, a left paramedian osteotomy was performed (between teeth 33 and 34) in the upper third of the symphysis; this was on account of a lack of space between teeth 31 and 41. Osteotomy of the lower two-thirds of the symphysis was performed medially. Nine patients underwent surgical maxillary expansion as part of the same procedure (fig. 10).

rin intratissulaire a e te pose chez 7 Un distracteur a` ve rin extratissulaire a e te utilise chez patients. Un distracteur a` ve les 28 autres patients. otomie a e te re alise en paraChez deux patients, le trait d’oste dian gauche (entre les dents 33 et 34) sur le tiers supe rieur me de la symphyse ; ceci pour des raisons de manque de place otomie des 2/3 infe rieurs a e te entre les dents 31 et 41. L’oste alise e en symphyse me diane. re te traite s par disjonction chirurgicale maxiNeuf patients ont e ^me temps ope ratoire (fig. 10). llaire dans le me

Activation of the distraction

Phase d’activation de la distraction

Average space gain at the level of the mental foramen was 7 mm (3–12, standard deviation 1.8 mm). Data were not available for 6 patients (fig. 11). The average activation rate was 1 mm/day, i.e. 4 turns/day (0.25–2).

te de Le gain de place interforamen mentonnier moyen a e cart-type 1,8 mm). Les donne es e taient man7 mm (3–12, e quantes pour 6 patients (fig. 11). tait de 1 mm/jour soit 4 La vitesse moyenne d’activation e tours/jour (0,25–2).

Malfunction of the temporomandibular joints was identified in 2 patients. Reasons for distraction: a mandibular tooth-arch discrepancy was apparent in all patients treated. In six cases, the discrepancy had reappeared after orthodontic treatment with extraction of mandibular premolars. In two patients, the mandibular incisors were missing (fig. 9).


89


[(Fig._10)TD$IG]

Fig. 10: Patient treated by maxillary and mandibular distraction in a context of sleep apnea syndrome: a: postoperative X-ray; b and c: activation phase of distraction; d: end of orthodontic treatment. par distractions maxillaire et mandibulaire dans le cadre d’un syndrome Fig. 10 : Patient traite es du sommeil : a : radiographie postope ratoire ; b et c : phase d’activation de la d’apne distraction ; d : fin de traitement orthodontique.

The average activation time was 28 days (10–45).

e moyenne d’activation a e te de 28 jours (10–45). La dure

Occlusal result and stability

sultat occlusal et stabilite Re

At the end of the active orthodontic phase

En fin de phase active orthodontique

A good occlusal result with a Class I dental relationship without labioversion of the mandibular incisors was obtained in 27 of the 35 cases (77%). In 19 of these 27 patients, secondary orthognathic surgery (11 sagittal osteotomies of the ramus for mandibular advancement and 8 bimaxillary osteotomies) was necessary to correct a sagittal discrepancy.

sultat occlusal avec une classe I dentaire sans vesUn bon re te obtenu chez 27 des tibuloversion incisive mandibulaire a e 35 patients (77%). Chez 19 de ces 27 patients, une chirurgie otomies sagittales des orthognathique secondaire (11 oste e mandibulaire et 8 oste obranches montantes d’avance te ne cessaire pour corriger le tomies bimaxillaires) a e calage sagittal. de

[(Fig._1)TD$IG]

Fig. 11: Distribution of patients according to inter-mental-foramen space gain. partition des patients en fonction du gain de place interFig. 11 : Re foramen mentonnier.

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The apnea-hyopnea index of the patient suffering from sleep apnea syndrome went down from 31 to 20/h after distraction and from 20 to 3.5/h after a secondary bimaxillary advancement osteotomy.

calage squelettique a Un gain sagittal avec correction du de te observe chez 4 patients. e sultat occlusal a` ce stade Huit patients n’ont pas eu de bon re du traitement : un stripping incisif pour corriger une vestibulo te ne cessaire chez 3 patients, l’avulsion version incisive a e te re alise e chez deux autres patients, un d’une incisive a e sentait une occlusion asyme trique avec une le ge re patient pre trique), classe II gauche (ceci a` la suite d’une distraction asyme et deux patients ont interrompu leur traitement. es du sommeil a vu son Le patient atteint de syndrome d’apne es hypopne es diminuer de 31 a` 20/h apre s la index d’apne s l’oste otomie d’avance e distraction et de 20 a` 3,5/h apre bimaxillaire secondaire.

Six months after the end of the active orthodontic phase

` 6 mois de la fin de la phase active orthodontique A

The occlusal result remained stable for a large majority of patients (32 out of 35): a trend towards recurrence of the overbite was observed in two patients, and labioversion of the incisors was noted in one case.

sultat occlusal est reste stable chez la grande majorite Le re cidive des patients (32 des 35 patients) : une tendance a` la re te observe e chez deux patients et une de la supraclusion a e vestibuloversion incisive est apparue chez un patient.

Complications

Complications

The most frequent complication was irritation of the labial and gingival mucosa due to the presence of the distractor: it was noted in 19 patients including the 7 patients equipped with the intra-tissular distractor screw. In one case, the labial lesion led to removal of the intra-tissue device and cessation of the treatment. The high frequency of mucosal irritation associated with the use of the intra-tissue distractor for the first seven patients treated led us to choose an extra-tissue distractor for the remaining 28 patients.

One breakage of the left mandibular plate of the device was observed on day 14 of the active distraction phase. One patient was lost to follow-up for 2 months during the postdistraction orthodontic treatment. During this time, he removed his orthodontic archwire and the space gained by distraction was lost.

quente a e te l’irritation des La complication la plus fre sence du dismuqueuses labiale et gingivale due a` la pre te note e chez 19 patients dont les 7 patients tracteur : elle a e rin intratissulaire. Pour une porteurs de disjoncteur a` ve quence le retrait patiente, la blessure labiale a eu pour conse rin intratissulaire et l’arre ^ t du traitede son disjoncteur a` ve quence d’irritation muqueuse lors de l’utiment. La grande fre rin intratissulaire pour les 7 prelisation du disjoncteur a` ve s nous a incite s a` utiliser un ve rin miers patients traite extratissulaire pour les 28 autres patients. te Un cas de parodontopathie avec inflammation gingivale a e me dicalement, et une forte de nudation sur une 31 a traite cessite une greffe gingivale chez un patient. ne Des douleurs au niveau des articulations temporomandibulaires sont apparues lors de la phase d’activation de la distraction chez deux patients asymptomatiques a` l’examen the rapeutique. Ces douleurs se sont estompe es en pre duisant la vitesse de 1 mm a` 0,5 mm/jour. re Une fracture de la plaque mandibulaire gauche du dispositif a te observe e a` j14 de la phase d’activation de la distraction. e te perdu de vue pendant deux mois en cours de Un patient a e traitement orthodontique postdistraction. Il avait au cours de riode retire son arc orthodontique et le gain de place cette pe te perdu. de la distraction avait e

Discussion

Discussion

Mandibular distraction osteogenesis by symphyseal osteotomy seems to offer a means of treating an anterior transversal mandibular deficit that is minimally invasive, fast, safe, and stable over time.

otomie symphyLa distraction osseuse mandibulaire par oste ^tre un traitement de l’insuffisance transsaire nous apparaıˆt e rieure peu invasif, rapide, suˆr et versale mandibulaire ante stable dans le temps.

A sagittal gain with correction of the skeletal discrepancy was observed in 4 patients. Eight patients did not benefit from a good occlusal result at this stage of treatment: stripping of the incisors to correct labioversion was necessary for three patients, in two cases an incisor was extracted, one patient had an asymmetrical occlusion with a slight Class II on the left (following asymmetrical distraction), and two patients ceased treatment.

One case of periodontal disease with gingival inflammation was treated medically, and for another patient severe denudation of 31 had to be treated by a gingival graft. Two patients, who had been asymptomatic before treatment, suffered from pain in the temporomandibular joints during the active phase of distraction. The pain lessened when the rate was reduced from 1 mm to 0.5 mm/day.


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Our study confirms the efficacy of this technique, as a Class I occlusion with no labioversion of the mandibular incisors was obtained in 77% of the patients treated. These results are comparable to those noted in the literature [10–13]. The secondary loss of space gained is generally explained by lack of anchorage for the posterior sectors, with mesial displacement. We believe therefore that the results could be improved if this risk was countered by early installation of a rigid lingual archwire at the start of the postdistraction orthodontic treatment. We included patients with a tooth-jaw discrepancy of more than 3 mm, since it appears that cases below this threshold can be treated orthodontically. The complications encountered seem relatively mild and thus acceptable. Just two patients complained of transient pain in the temporomandibular joints; no cases of temporomandibular joint dysfunction syndrome were encountered during treatment. These results can be explained by the ability of the condyles to adapt [14], and are comparable to those noted in other studies [7,10]. There was no irreversible loss of tooth vitality during our study. We believe that this result was due to rigorous operating procedure and to precise planning, with the orthodontist, of the alveolar osteotomy incision. Unlike the basilar osteotomy incision, which must be strictly median so as to ensure symmetrical distraction, the alveolar osteotomy can be paramedian if the space between the central incisors seems insufficient. This was in fact the situation for two of our patients, with no detrimental impact on the occlusal result.

The group of Atlan et al. [10] suggests that this distraction could be performed under local anesthesia with a dental anchorage system. We believe that general anesthesia is more comfortable both for the patient and the surgeon. In addition, symphyseal distraction can be performed at the same time as another procedure requiring general anesthesia (maxillary expansion, extraction of wisdom teeth). According to Del Santo et al. [15], distraction performed with dental anchorage could lead to greater lengthening at alveolar level than at basal level since the forces are then applied above the center of resistance of the mandible. Similarly, Salvodelli et al. [16], using a skeletally-anchored device, report basilar expansion that is greater than the alveolar expansion. They explain this result by the fact that the distractor is often fixed below the mandibular center of resistance because of local constraints imposed by the position of the dental roots. To obtain symmetrical distraction, Mommaerts et al. [12,17] propose a system with a double anchorage, both dental and skeletal. In the light of our results, it seems justifiable to suggest the use of a bone-anchored device to obtain a parallel dentoalveolar and basilar distraction [11], accepting a slightly higher rate of local complications (inflammation and gingival irritation)

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tude retrouve une bonne efficacite de cette technique Notre e avec une occlusion en classe I sans vestibuloversion incisive s. Ces re sultats mandibulaire chez 77 % des patients traite s dans la litte rature [10– sont comparables a` ceux retrouve e le plus 13]. La perte secondaire du gain de place est explique rieurs souvent par une perte d’ancrage des secteurs poste rive me siale. Nous pensons ainsi pouvoir ame liorer avec de sultats en pre venant ce risque avec un arc lingual rigide nos re pre cocement en de but de traitement orthodontique pose postdistraction. sentant une DDM Nous avons inclus les patients pre rieure a` 3 mm, car en dessous de cette valeur, cette supe re apparaıˆt accessible a un simple traitement dernie orthodontique. es nous paraissent peu graves et Les complications retrouve acceptables. Des douleurs transitoires aux articulations temte de crites chez seulement deux poromandibulaires ont e patients et aucun syndrome algodysfonctionnel des articulacours du traitement. tions mandibulaires n’est apparu au de sultats s’expliquent notamment par la capacite adaptaCes re s tive des condyles [14] et sont comparables a` ceux retrouve tudes [7,10]. Aucune atteinte de finitive de la dans d’autres e dentaire n’a e te observe e dans notre e tude. Nous penvitalite ratoire ainsi qu’une planification sons qu’une rigueur ope cise avec l’orthodontiste du trait d’oste otomie alve olaire a pre sultats. Contrairement au trait d’oste otomie basipermis ces re ^tre re alise en me dian strict pour une distraction laire qui doit e trique, le trait d’oste otomie alve olaire peut e ^tre re alise en syme dian si l’espace entre les deux incisives centrales ne parame paraıˆt pas assez important. En effet, 2 de nos patients ont subi otomie alve olaire parame diane sans conse quence une oste faste sur le re sultat occlusal. ne quipe de Atlan et al. [10] propose ainsi de re aliser cette L’e sie locale avec un dispositif a` ancrage distraction sous anesthe sie ge ne rale a un inte re ^t dentaire. Nous pensons que l’anesthe pour le confort du patient et du chirurgien. De plus, la distrac^tre re alise e dans le me ^me temps tion symphysaire peut e ratoire qu’un autre geste ne cessitant une anesthe sie ope ne rale (disjonction maxillaire, avulsion de dents de ge alise e sagesse). Selon Del Santo et al. [15], la distraction re avec un dispositif a` ancrage dentaire engendrerait un allongeolaire plus grand que l’allongement basal. Ceci serment alve es sont alors au-dessus du ait duˆ au fait que les forces applique sistance de la mandibule. A contrario, l’e quipe de centre de re crit une expansion basilaire plus grande que Salvodelli [16] de olaire en utilisant un dispositif a` ancrage l’expansion alve sultat par le fait que le distracteur osseux. Il explique ce re en dessous du centre de re sistance de la est souvent fixe mandibule a` la suite des contraintes locales de position des trique, apex dentaires. Pour obtenir une distraction syme Mommaerts et al. [12,17] propose un dispositif a` double ancrage osseux et dentaire. sultats, il nous semble justifie de proposer Au vu de nos re d’utiliser un dispositif a` ancrage osseux pour obtenir une disle alve olodentaire et basilaire [11], en tole rant traction paralle un taux de complications locales (inflammation et irritations




[10], but avoiding the risk of promoting predominantly dentoalveolar growth, which is described as being unstable over time [18]. How soon after distraction orthodontic tooth movement should be resumed is subject to debate. Some authors consider that early movement threatens tooth vitality and recommend waiting for the bone to consolidate [15,19,20]. We believe, on the contrary, that it is advantageous to initiate tooth movement early (2 weeks after the end of distraction) since histologically orthodontic tooth movement leads to a phase of appositionresorption on the alveolar bone, thereby accelerating the process of bone maturation. Early orthodontic movement would also make it possible to increase bone volume by the formation of alveolar bone [21,22]. In four of our patients who were initially skeletal Class II, an anteroposterior gain was observed, and since the sagittal discrepancy had significantly diminished after symphyseal distraction orthognathic surgery was no longer indicated. This impact of anterior distraction on the sagittal dimension was described by Delaire [23] for the upper jaw: “Lateral displacement of the anterior segment of the dental arch leads both to an increase in its projected length X and its real length Y (perimeter)” (fig. 12). Symphyseal distraction by median osteotomy thus makes it possible to treat both a tooth-jaw discrepancy due to anterior transversal mandibular deficit and a slight skeletal Class II without secondary orthognathic surgery. Success of the treatment seems to us to depend essentially on good collaboration between the orthodontist and the surgeon and on rigorous patient selection. This selection should, in particular, take into account: patient observance of treatment (the latter being active during the active phase of distraction), orodental hygiene, and the initial periodontal status.

ge rement plus e leve [10], et en ne prenant pas le gingivales) le aliser une croissance principalement denrisque de re olaire, ceci e tant de crit comme instable dans le temps toalve [18]. cocite de reprise des mouvements dentaires orthodonLa pre s la distraction est discute e. En effet, certains tiques apre rent celle-ci comme risque e pour la vitalite auteurs conside dentaire et recommandent d’attendre la consolidation osseuse [19,15,20]. Nous pensons au contraire qu’il y a un re ^ t a` initier les mouvements dentaires pre cocement inte s la fin de la distraction) : en effet, histologi(2 semaines apre quement, un mouvement dentaire orthodontique entraıˆne une sorption sur l’os alve olaire et acce le re le phase d’apposition re placement orthodonprocessus de maturation osseuse. Un de coce permettrait e galement d’augmenter le volume tique pre olaire [21,22]. osseux par formation d’os alve sentaient initialement une Chez 4 de nos patients qui pre roposte rieur a e te observe . classe II squelettique, un gain ante s distraction symphysaire, le de calage sagittal En effet, apre , la chirurgie orthognathique n’e tait ayant fortement diminue e. Cet effet engendre par la distraction ante rieure plus indique te de crit par Delaire [23] au sur la dimension sagittale a e rieur : « Le de placement late ral niveau du maxillaire supe rieures de l’arcade dentaire se traduit a` la fois des parties ante e X et de sa longpar un allongement de sa longueur projete elle y (pe rime tre) » (fig. 12). ueur re otomie me diane peut ainsi La distraction symphysaire par oste permettre de traiter a` la fois une DDM par insuffisance transrieure et une le ge re classe II squeversale mandibulaire ante lettique sans chirurgie orthognathique secondaire. ussite du traitement nous paraıˆt reposer essentiellement La re sur une bonne collaboration entre l’orthodontiste et le chirurlection rigoureuse des patients. Cette gien et sur une se lection devant prendre en compte notamment : l’adhe sion se tant actif lors de la phase du patient au traitement (ce dernier e ne buccodentaire et l’e tat d’activation de la distraction), l’hygie

[(Fig._12)TD$IG]

Fig. 12: Effect of anterior distraction on the sagittal dimension described by Delaire [23] for the upper jaw. par la distraction ante rieure sur la dimension Fig. 12 : Effet engendre crit par Delaire [23] au niveau du maxillaire supe rieur. sagittale de


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Treatment by symphyseal distraction requires perfect coordination between the surgeon and the orthodontist. The role of the orthodontist is indeed essential throughout treatment:

— during the active phase of distraction, to manage the rate of distraction and its duration, depending on the gain required; — after activation, by restoring good occlusion, which guarantees stability.

parodontal initial. Un traitement par distraction symphysaire cessite une coordination parfaite entre le chirurgien et ne ^ le de l’orthodontiste est en effet essentiel l’orthodontiste. Le ro tout le long du traitement : ope ratoire pour se curiser le geste d’oste otomie en — en pre verrouillant le installant une divergence radiculaire et en de maxillaire ; rant la vitesse de — lors de la phase active de distraction en ge e en fonction du gain ne cessaire ; distraction et la dure s l’activation en restaurant une bonne occlusion, ceci — apre tant le garant de la stabilite . e

Disclosure of interest

claration d’inte re ^ts De

The authors declare that they have no conflicts of interest concerning this article.

clarent ne pas avoir de conflits d’inte re ^ ts en Les auteurs de relation avec cet article.

— preoperatively, to ensure the safety of the osteotomy procedure by creating root divergence and unlocking the maxilla;

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