Laure Frapier

Impact of genioplasty on mandibular growth during puberty.

AIM Genioplasty has been validated for the correction of mandibular vertical excess and is generally performed at the end of the growth period, either alone or in association with other forms of osteotomy. Our aim was to assess whether genioplasty performed at an earlier age can impact mandibular growth. METHODS This comparative prospective study included 25 high-angle, mouth-breathing adolescents following orthodontic and ENT treatment. Subjects were divided into two groups according to their stage of puberty, either early (group 1: Tanners stage 3, n=12) or late stage (group 2: Tanner stage 4-5, n=13). Genioplasty was performed in both groups. Cephalometric comparison was made on the overall population and for each group, before and after genioplasty (at 1, 6, 12 and 18months). RESULTS In the immediate postoperative period, significant variation of all the cephalometric measures was observed within each group showing reduction of the vertical dimension and sagittal augmentation. Eighteen months post-surgery, only group 1 exhibited a significant increase in SNPog. Augmentation of the SNB and anterior mandibular rotation were also significantly greater in group 1. The difference in the direction of growth of the mandible before genioplasty (18months of orthodontics) and postgenioplasty (18months of postoperative monitoring) was also significant. CONCLUSION Early genioplasty permits redirection of mandibular growth conducive to orthopedic correction of high angle Class II.

Ventilatory disorders and facial growth: Benefits of early genioplasty

AIM The purpose of this prospective study was to determine whether combined functional genioplasty and orthodontic treatment in patients with vertical mandibular growth can be beneficial not only in achieving an esthetic outcome and orthodontic stability but also for the multi-disciplinary management of oral ventilation. METHODS Twenty-five non-obese adolescents (mean age: 14.6 ± 1.4 years) with vertical excess of the lower third requiring genioplasty received surgery following orthodontic treatment. All were predominantly mouth-breathers despite ENT treatment and rehabilitation. The functional before-after impact of genioplasty was examined in a clinical setting using polysomnography. RESULTS Before genioplasty, 52% of the adolescents presented an upper airways resistance syndrome (UARS) with obstructive hypopnea and poor sleep quality. Three to 6 months after genioplasty, the mode of ventilation shifted from oral to nasal (p < 0.001). Lip seal was significantly restored with no contraction of the labio-mental muscles. All nighttime symptoms improved. The proportion of patients suffering from ronchopathy (pathological snoring), dry mouth and disturbed sleep dropped significantly (p = 0.08, p = 0.001, p = 0.0009, respectively). Respiratory events and sleep pattern became normal. Below, we present two clinical reports involving obstructive sleep apnea syndrome (OSAS). CONCLUSIONS Genioplasty performed during puberty promotes spontaneous lip closure and helps restore nasal ventilation. It improves the obstructive disorder and its manifestations during sleep.

La Classe II, 2 dans tous ses états

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.

Successful orthodontic-surgical treatment: aiming for esthetics and function. Analysis of some clinical cases.

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.

Effets de l’impaction maxillaire et de la génioplastie, dans le sens vertical

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.

Le jeu fonctionnel dans la correction et la stabilité des incisives

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.

A genetic heritage; the same yet different: A comparative study in twins

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.

Même patrimoine génétique et pourtant différents : étude de cas comparative de jumeaux

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.

Predictive factors for resorption of teeth adjacent to impacted maxillary canines

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.