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Summary Introduction The treatment of adult patients presenting an open bite is a real challenge for orthodontists due to the complexity of the malocclusion. The diagnosis is essential to identify aetiological factors and establish the best aesthetic and functional therapeutic prognosis. Among the aetiological factors, iatrogenic treatment history has to be considered. It is the case here where a regrettable unsuitable splint for bruxism treatment forced an open bite to appear. Material and method This case report presents an adult women with a large open bite due to an occlusal splint not covering the last mandibular molars. It was not really a vertical skeletal excess but more a mandibular clockwise rotation linked to the molar extrusions, which created a dento-alveolar open bite and labio-mental contractions during lip closure. Treatment objectives were the intrusion of the third and second molars, the extrusion of incisors to obtain a counter clockwise mandibular rotation. The patient was treated with an aesthetic and customized lingual appliance with no orthognathic surgery. A physiotherapy was followed by the patient when the open bite was closed in order to facilitate and stabilize the intercuspation. Results A complete closing of the open bite was reached after two years of treatment. The superimposition showed the anticlockwise mandibular rotation. The levelling with posterior intrusion and the incisors extrusion reduced the vertical dimension with success. After 3 years of retention, the occlusal stability was obtained. Conclusion The intrusion of the molars associated with a counter clockwise mandibular rotation made it possible the incisor extrusion. The occlusal balance with physiotherapy and patient compliance maintained the closure. In this way, the iatrogenic effects of the poorly designed bite splint were repaired.

Summary Introduction Unilateral posterior crossbite (UPCB), often from dysfunctional and para-functional causes, leads to positional mandibular asymmetries that can develop at a very young age into skeletal mandibular deviation; hence the interest of early maxillary expansion. The purpose of this retrospective study was to compare the impact of maxillary expansion by Quad Helix (QH) on mandibular skeletal asymmetry correction before and after 7 years of age. Materials and methods All children with UPCB and skeletal mandibular asymmetry, who were treated by QH in the orthodontic department of Montpellier between February 2017 and August 2018 and had a radiography file at baseline (T0) and 12 months later (T1) were retrospectively included. The patients were divided into two groups according to age: under 7 years of age with QH adjusted on second primary molars (early group G1) and over up to 13 years old with QH adjusted on first permanent molars (late group G2). The differences between the right and left sides of the mandible in corpus length ΔL (main eligibility criterion) and ramus height ΔH (secondary criterion) were compared between groups. X2 test, Fisher's exact test and Wilcoxon rank-sum tests were used for baseline comparisons. A multifactorial analysis allowing adjustment on possible confounding factors was used with R software. Results Out of 67 patients files only 40 were completed and analysed: 13 in G1 and 27 in G2. These groups were comparable at baseline except for the age parameter. Taking into account the initial severity of asymmetry, the analysis of covariance showed a significant intergroup difference with higher correction in the early group of the corpus asymmetry (+1.0; P = 0.008). On the contrary, no significant differences were observed between the groups in the ramus asymmetry correction. Conclusions Within the limits of this retrospective study, the early unilateral posterior occlusion correction by QH can better reduce both positional and contour mandibular asymmetries in patients under 7 years of age.

Background/objective To reproduce the methods and results of the study by Alobeid et al. (2018) in which the efficacy of tooth alignment using conventional labial and lingual orthodontic bracket systems was assessed. Materials/methods We used the identical experimental protocol and tested (i) regular twin bracket (GAC-Twin [Dentsply]) and lingual twin bracket systems (Incognito [3M]), (ii) together with NiTi 0.014” wires (RMO), and (iii) a simulated malocclusion with a displaced maxillary central incisor in the x-axis (2 mm gingivally) and in the z-axis (2 mm labially). Results The method described by Alobeid et al. (2018) is not reproducible, and cannot be used to assess the efficacy of tooth alignment in labial or lingual orthodontic treatment. Major flaws concern the anteroposterior return of the Thermaloy-NiTi wire ligated with stainless steel ligatures. The reproduced experimental setting showed that a deflected Thermaloy-NiTi wire DOES NOT move back at all to its initial stage (= 0 per cent correction) because of friction and binding (see supplemented video), neither with the tested labial nor with the lingual brackets. Furthermore, an overcorrection of up to 138 per cent, which the authors indicate for some labial bracket-wire combinations and which deserves the characterization “irreal”, stresses the inappropriateness of the method of measurement.Further flaws include: a) incorrect interpretation of the measurement results, where a tooth tripping around (overcorrection) is interpreted as a better outcome than a perfect 100 per cent correction; b) using a statistical test in an inappropriate and misleading way; c) uncritical copying of text passages from older publications to describe the method, which do not correspond to this experimental protocol and lead to calculation errors; d) wrong citations; e)differences in table and bar graph values of the same variable; f) using a lingual mushroom shaped 0.013” Thermaloy-NiTi wire which does not exist; g) drawing uncritical conclusions of so called "clinical relevance" from a very limited in vitro testing. Conclusions Clinical recommendations based on in vitro measurements using the Orthodontic Measurement and Simulation System (OMSS) should be read with caution.

Summary Dysfunctional deviations such as dysfunctional swallowing and chewing manifest as transverse arch discrepancies giving rise to positional asymmetry of the condyles and glenoid fossae with a more or less significant skeletal impact. This results almost inevitably in asymmetric occlusion in the sagittal dimension. Drawing on clinical cases, we will show which treatment strategies to adopt and which occlusal criteria to observe for finishing and stability.

Summary Since the 19th century, and in every field of medicine, monozygotic twins have been studied to assess the involvement of genetic and environmental factors in phenotypic expression. The phenotype/genotype relationship remains the leading problem in contemporary biology. In dentofacial orthopedics, this relationship is of relevance in the three-dimensional approach to the face, in both diagnosis and treatment. The present study of two monozygotic twins presenting skeletal class III malocclusions which were genetic yet different is a clear illustration of the interaction of genotype and epigenetic factors with environmental influences. We will demonstrate that treatment can reduce phenotypic differences.

Resume Depuis le XIXe siecle, dans tous les domaines de la medecine, l’analyse des jumeaux monozygotes permet d’evaluer la participation des facteurs genetiques et environnementaux dans l’expression phenotypique. La relation phenotype/genotype reste le probleme principal de la biologie contemporaine. En orthopedie dentofaciale, cette relation est importante dans l’approche tridimensionnelle de la face tant sur le plan diagnostic que therapeutique. Notre etude de deux jumelles monozygotes, presentant des classes III squelettiques genetiques mais pourtant differentes, illustre bien l’interaction du genotype et des facteurs epigenetiques avec les facteurs environnementaux. Nous montrerons que la therapeutique permet d’attenuer les differences phenotypiques.

Summary Purpose The aim of this study was to assess the link between the degree of resorption of teeth adjacent to an impacted maxillary canine and the situation of the latter so as to identify factors predictive of resorption. Material and methods This was a retrospective study concerning all patients with impacted maxillary canines who consulted the orthodontics department at the Center for dental care, teaching and research (CSERD) in Montpellier between 2010 and 2015, with a full radiological file including panorex, periapical long-cone and cone-beam images. In all, 25 patients with 31 impacted maxillary canines were analyzed. Measurements were made by a single operator using 2D images and 3D analysis; they concerned the quantitative and qualitative aspects of resorption of teeth adjacent to the impacted canines and also evaluation of the position of the maxillary canine and its follicular sac. The X2 test was used to compare percentage resorption in men and women. Analysis of variance (ANOVA) was applied to compare the average degree of resorption of the adjacent teeth depending on the sagittal or vertical position of the impacted maxillary canine. Covariance analysis (ANCOVA) was used to study the average degree of resorption taking jointly into account the sagittal, vertical and transverse positions and adjusting for age and sex. Calculations were performed with a significance threshold of 5% using MyStat® software. Results Women made up 60.6% of the study population, with no significant age differences between the two sexes (21 ± 5 years). The risk of adjacent resorption was not linked to age but was significantly greater (P-value = 0.03) for women (60%) than for men (23%). The average degree of resorption is explained jointly by sagittal position (P-value = 0.0001) and transverse position (P-value = 0.01), after adjustment for age and sex. On the other hand, the average degree of resorption was not linked to vertical position, nor to the shape or size of the follicular sac. Conclusion This study leads to the conclusion that the risk of resorption of the lateral incisor is not linked to the buccal or palatal situation of the canine. The risk is greater when the canine is vertically above the lateral incisor root and close to the median palatine suture, suggesting a mechanical blockage by the apex of the lateral incisor.

International audience; Dear members and subscribers of International Orthodontics,Following the establishment of the European College of Orthodontics (CEO) in 1967 by RogerO'Meyer and with Paul Brender, a "News Bulletin'', regular summary report of the College'sscientific meetings was published. It was replaced over 20 years ago by the Journal de l'Edgewiseunder the editorship of André Horn and Alain Decker successively. In 2003, driven by JosephGiordanetto, the journal became officially bilingual and was renamed International Orthodontics.From that day, it was indexed on ScienceDirect and then on Medline from 2008, thanks to thepublisher Elsevier-Masson and the great involvement of the editor in chief Jean-Pierre Ortial. In2018, it is with great honour that I took the responsibility of the redaction. In response to thesteady increase in the distribution of the journal and in the number of articles from all overthe world, the model of the journal is changing in 2019 for an "only English'' format and an onlinesubmission system for the authors. This inevitable change also supports the legitimate need toincrease our impact factor. We would like to thank the authors for their scientific contribution ofthe highest quality. With the editorial board, we will ensure, while encouraging research andinnovation, that the clinical and ethical dimensions of the publications are maintained, as they area pillar of the European College of Orthodontics.

Resume Objectif La ventilation orale est une dysfonction qui retentit sur la croissance craniofaciale et dento-alveolaire ainsi que sur l’anatomie des voies aeriennes superieures (VAS). Elle se manifeste notamment par un mauvais calibrage des VAS perturbe par l’hypertrophie de l’anneau de Waldeyer et par un exces vertical de l’etage inferieur responsable d’une beance labiale qui entretient la dysfonction. L’objectif principal de cette etude etait d’evaluer l’evolution de la sphere oropharyngee chez de jeunes patients hyperdivergents ayant beneficie d’une genioplastie fonctionnelle dans le cadre d’un traitement orthodontique. Methodes Il s’agit d’une etude retrospective comparative menee sur 47 adolescents, hyperdivergents, non obeses, ventilateurs oraux exclusifs ou diurnes, traites au Centre de soins, d’enseignement et de recherche dentaires (CSERD) de Montpellier. Tous relevaient d’une indication de genioplastie precoce de reduction du sens vertical en cours ou en fin de traitement : 23 operes avaient beneficie d’une genioplastie fonctionnelle, et 24 temoins avaient recu uniquement un traitement orthodontique. La comparaison de l’evolution des mesures cephalometriques des aires oro- et nasopharyngees entre les deux groupes et maxillomandibulaires a ete realisee par analyse de covariance (ANCOVA) permettant un ajustement sur des facteurs de confusions. Resultats Concernant les structures squelettiques : dans le sens sagittal, la genioplastie concourt a une projection symphysaire significativement plus elevee dans le groupe opere que dans le groupe temoin ( p p p = 0,033). Meme constat a l’etage de l’oropharynx, ou l’espace linguopharynge revele une augmentation significative dans le groupe opere ( p Conclusion La genioplastie precoce realisee chez l’adolescent en cours de croissance, en favorisant l’occlusion labiale spontanee, participe au recalibrage des VAS.

Adult patients who consult an orthodontist are looking for dental rehabilitation underpinned by an implicit esthetic demand, which needs to be analyzed. When the discrepancy involves more than the teeth and cannot be corrected by dentoalveolar compensation alone, there is a need, on account of the lack of growth, the periodontal setting and underlying dysfunctions, for an orthodontic-surgical solution. A clear understanding of the required future functional balance will help achieve a satisfactory esthetic target and give stable, lasting results.

Resume Les patients adultes qui consultent en orthodontie ont un desir de rehabilitation dentaire avec une demande esthetique implicite qu’il faut bien analyser. Quand la dysharmonie n’est pas seulement dentaire et ne peut relever de compensation orthodontique dentoalveolaire, elle est de resolution orthodonticochirurgicale, en raison de l’absence de croissance, du contexte parodontal et des dysfonctions sous-jacentes. C’est de la bonne comprehension du nouvel equilibre fonctionnel necessaire que resulteront la satisfaction de l’objectif esthetique et la perennite du resultat.

Resume Objectif Le propos de cette etude prospective etait de savoir si la genioplastie fonctionnelle associee a l’orthodontie chez les patients a croissance mandibulaire verticale, presente, outre un interet esthetique et de stabilite orthodontique, un interet dans la prise en charge pluridisciplinaire de la ventilation orale. Methodes Vingt-cinq adolescents, d’une moyenne d’âge 14,6 ± 1,4 ans, non obeses, avec un exces vertical du tiers inferieur de la face justifiant une genioplastie, ont ete operes en fin d’orthodontie. Ils avaient une ventilation a predominance orale malgre prise en charge ORL et reeducation. L’impact fonctionnel de la genioplastie a ete analyse du point de vue clinique et polysomnographique par comparaison avant–apres. Resultats Avant genioplastie, 52 % des adolescents presentaient un syndrome de resistance des voies aeriennes superieures avec hypopnees obstructives et faible efficacite du sommeil. Trois a six mois apres genioplastie, le mode de ventilation change d’oral en nasal (p Conclusions La genioplastie a l’âge pubertaire, en favorisant la fermeture labiale spontanee, permet de recouvrer la ventilation nasale. Elle ameliore la pathologie obstructive et ses manifestations lors du sommeil.

Resume Objectif : la genioplastie, habituellement pratiquee en fin de croissance, isolee ou associee a d’autres osteotomies est validee pour traiter l’exces vertical. Notre objectif est d’evaluer si la genioplastie a un âge plus precoce a un impact sur la croissance mandibulaire. Methodes : il s’agit d’une etude prospective comparative. Vingt-cinq adolescents, hyperdivergents, ventilateurs buccaux, ont ete inclus apres orthodontie et traitement ORL. Ils sont divises en deux groupes selon l’âge pubertaire, precoce (groupe 1 : Stade de Tanner 3, n = 12) ou tardif (groupe 2 : Stade de Tanner 4–5, n = 13). La genioplastie a ete proposee dans les deux groupes. Une comparaison cephalometrique a ete realisee sur la population globale et pour chaque groupe, avant-apres genioplastie (a un, six, 12, 18 mois). Resultats : en postoperatoire immediat, il existe au sein de chaque groupe une variation significative de toutes les mesures cephalometriques dans le sens d’une diminution du sens vertical et d’une augmentation sagittale. Dix-huit mois apres la chirurgie, seul le groupe 1 montre une augmentation significative de SNPog. L’augmentation de SNB et la rotation mandibulaire anterieure sont aussi significativement plus importantes dans le groupe 1. Il existe une difference significative de direction de croissance mandibulaire entre la periode pregenioplastie (18 mois d’orthodontie) et post-genioplastie (18 mois de surveillance postoperatoire). Conclusion : la genioplastie precoce permet une reorientation de la croissance mandibulaire favorable a la correction orthopedique de la Classe II hyperdivergente.

La susceptibilite ou la resistance a la resorption radiculaire secondaire a l’application d’une force orthodontique releve de facteurs genetiques. Cependant, la resorption radiculaire est d’etiologie plurifactorielle et represente un risque iatrogene non-intentionnel qui, pour ne pas etre une mauvaise surprise, doit etre decelee le plus tot possible, faire l’objet de surveillance radiologique et de precaution therapeutique. Nous etablirons la conduite generale a tenir face aux resorptions radiculaires avant, pendant et apres le traitement orthodontique, en insistant sur la surveillance radiologique, sur le temps necessaire a la reparation cementaire et sur la strategie mecanique individualisee selon le risque et l’âge du patient. Nous illustrerons les resorptions les plus frequentes, celles liees a des facteurs locaux, celles qui sont les signes discrets de deficiences constitutionnelles (situation d’agenesies, de dents incluses, de transposition, d’anomalies radiculaires c’est-a-dire racines emoussees, coudees, en pipette, invaginees ou liees a un traumatisme). Dans tous les cas, l’information du risque de resorption doit etre donnee, accompagnee d’un consentement eclaire en soulignant les benefices et les risques du traitement et de son abstention. Les facteurs aggravants parafonctionnels et dysfonctionnels doivent etre signales. Pour les cas de resorptions severes superieures a 4 mm avec un rapport couronne / racine de 1/1, une declaration de sinistre doit etre faite a l’assurance.

L'introduction recente des nouveaux systemes d'ancrages intra-osseux appeles mini-vis, permettant une mise en charge immediate, a revolutionne l'approche clinique et biomecanique de l'ancrage en orthodontie. L'insertion trans-gingivale par un tournevis manuel se fait aisement et le plus frequemment sans avant-trou. L'objectif de cette etude experimentale est de demontrer que la realisation d'un avant-trou limite les contraintes intra-osseuses lors du vissage, ceci ayant des consequences a court terme sur la stabilite primaire des mini-vis et a long terme sur leur maintien. Materiels et methodes : deux mini-vis auto-forantes et auto-taraudantes Aarhus Medicon de diametres 1,6 et 1,3 mm sont vissees avec un tournevis manuel, sans puis avec un avant-trou, dans une lamelle d'os cortical fixee sur un capteur mesurant les forces et le couple. Resultats : la realisation d'un avant-trou dans l'os cortical diminue significativement la force verticale maximale (FVM) au debut du vissage (p : le vissage sans avant-trou conduit au delabrement de la couche osseuse superficielle par l'apparition de microfractures limitant les possibilites de blocage des mini-vis.

Resume Le point commun de toutes les formes cliniques des Classes II, 2 est la supraclusion, le plus souvent en « couvercle de boite », avec inclinaison palatine caracteristique des incisives maxillaires. La severite de la forme clinique depend de l’enveloppe musculaire predominante tant au niveau de la sangle elevatrice qu’au niveau de la levre inferieure. L’empreinte genetique est la, mais se greffent les problemes dysfonctionnels qui compliquent le tableau clinique. Le schema vertical squelettique est tres souvent celui d’une rotation anterieure, mais il peut etre variable tout comme le sens sagittal. L’importance de la Classe II squelettique et dentaire depend des verrous verticaux et transversaux ainsi que de la derive mesiale de l’arcade maxillaire a la suite de la dystopie primitive des canines maxillaires. Dans toutes les Classes II, 2 primitives ou fonctionnelles, l’environnement musculaire est crucial a considerer, tant du point de vue etiologique que sur le plan therapeutique.

International audience; AIM:Mouth breathing is a functional disorder that affects craniofacial and dento-alveolar growth and also upper airway (UA) anatomy. This is apparent mainly in dimensional abnormalities of the UA caused by hypertrophy of Waldeyer's ring and excessive vertical development of the lower part, giving rise to labial incompetence that perpetuates the functional disorder. The main aim of this study was to evaluate the development of the oropharyngeal structures in young hyperdivergent patients who had undergone functional genioplasty in the context of orthodontic treatment.METHODS:This is a comparative retrospective study performed on 47 adolescents who were hyperdivergent, non-obese and exclusive or diurnal mouth breathers, treated at the Centre de soins, d'enseignement et de recherche dentaires (CSERD) in Montpellier, France. All were candidates for early genioplasty for vertical reduction, and were undergoing or at the end of treatment: 23 had been treated surgically (functional genioplasty), and 24 controls had received orthodontic treatment alone. Inter-group comparison of the changes in cephalometric measurements of the oro- and nasopharyngeal zones and maxillomandibular measurements was performed using covariance analysis (ANCOVA) to adjust for confounding factors.RESULTS:Concerning the skeletal structures: in the sagittal dimension, genioplasty led to significantly greater projection of the symphysis in the surgical group than in the control group (P

Resume Le jeu fonctionnel implique dans la ventilation, dans les fonctions de mastication-deglutition et dans l’equilibre de repos, intervient dans la position des incisives. L’orthodontie par son action alveolo-dentaire aide les structures cranio-faciales vers une meilleure harmonie en adequation avec la physiologie musculaire. Le but de cette etude clinique est de montrer que la reeducation fonctionnelle peut etre un atout avant meme le traitement orthodontique, mais qu’elle optimise aussi la mecanique en neutralisant les forces musculaires dysfonctionnelles et parafonctionnelles perturbant le guide incisif. Elle a toute son acuite apres le traitement orthodontique pour perenniser les resultats.

Resume Objectifs Quel que soit le controle prechirurgical des plans d’occlusion, il est assez illusoire de corriger un probleme de divergence mandibulaire par osteotomie mandibulaire isolee. La chirurgie maxillaire, plus ou moins associee a unegenioplastie, permet de traiter le sens vertical d’une facon optimale. Methodes L’effet sur le sens vertical de l’impaction maxillaire et de la genioplastie de transposition anterieure a ete etudie, d’une facon retrospective, sur une population de 22 patients hyperdivergents, d’âge moyen 22 ± 4 ans, tous traites par le meme chirurgien selon un protocole Le Fort I d’avancee et d’impaction. De plus, 12 ont eu une chirurgie mandibulaire et 8 ont beneficie d’une genioplastie. Resultats Pour la population totale, a l’etage maxillaire, l’impaction anterieure moyenne etait de 3,7 ± 3 mm ; l’impaction posterieure moyenne etait de 3,4 ± 2 mm ; l’avancee moyenne etait de 6,3 ± 2 mm. L’avancee mandibulaire resultante moyenne etait de 3,8 ± 3 mm. Apres chirurgie, une diminution du sens vertical existait au sein de la population totale. Celle-ci etait encore plus nette (p = 0,008) dans le groupe avec genioplastie (I : 8 patients) alors qu’elle n’etait pas sensible (p = 0,09) dans le groupe sans genoplastie (II : 14 patients). De plus, il existait une difference significative entre les groupes I et II quant a l’impaction et la rotation anterieure du maxillaire (p = 0,047) avec des valeurs plus importantes dans le groupe I. La rotation mandibulaire squelettique anterieure resultante, mesuree sur les superpositions structurales de Bjork-Nielsen, etait comparable dans les deux groupes I et II. En revanche, la composante anterieure intramatricielle mandibulaire est plus grande dans le groupe I (p = 0,02), d’ou l’impact plus important sur le sens vertical.

The recent introduction of the new systems of intraosseous anchorages called mini-screw, allowing an immediate loading, has revolutioned the clinical and biomechanical approach of anchorage in orthodontics. Trans-gingival insertion by a manual screwdriver is done easily and most frequently without before-hole. The goal of this experimental study is to show that the realization of a before-hole limits the intraosseous constraints during screwing. This having short-term effects on the primary stability of the mini-screws and long-term effects on their maintenance.two self-drilling and self-tapping mini-screws Aarhus Medicon of 1.6 and 1.3 mm diameters are screwed with a manual screwdriver, without then with a before-hole, in a plate of cortical bone fixed on a sensor measuring the forces and the couple.the realization of a before-hole in the cortical bone significantly decreases the maximum vertical force (FVM) at the beginning of screwing (p0.0001) and the maximum screwing couple (CVM) at the end of the screwing (p0.0001), this independently the diameter of the screw.screwing without before-hole led to the alteration of the osseous surface layer caused by micro fractures which limit the possibilities of blocking of the mini-screws.