[Orthognathic surgery of mandibular asymmetry: which results can we expect with and without chin wing? A cohort out of 51 cases]. / Traitement ortho-chirurgical de la latéromandibulie : quels résultats escompter avec et sans chirurgie du contour mandibulaire ? Une étude de cohorte sur 51 cas.

INTRODUCTION: The aim of this retrospective cohort is to evaluate the amount of postsurgical correction of soft and hard tissues in patients with mandibular asymmetries and to compare the results with and without surgery of the lower mandibular contour (chin wing…). MATERIAL AND METHOD: Mandibular asymmetries cases of three surgeons were systematically included. The angles of deviation of the chin, bi-commissural, bi-gonic and occlusal were measured on face photography and radiography. A pre and post-surgical comparison was performed and the amount of correction was analyzed via the Wilcoxon statistical test. RESULTS: 51 patients (44 women and 7 men) were included. After surgery, the correction is significant for all measurements with an improvement of 44 to 60% depending on the measured angles. No patient is normalized but the small initial mandibular asymmetries are the closest to normal after surgery. The correction of the bi-commissural angle is controlled without being optimal (60% correction). The difficulty remains the horizontalization of the bi-gonial plan which is only corrected at 45%. Patients with mandibular margin surgery (chin wing…) showed the greatest improvement in bi-gonial (p = 0.0142) and occlusal (p = 0.0154) angles. CONCLUSION: If surgery allows a significant correction of facial dissymmetry, this is not complete. Surgical procedures on the lower edge of the mandible such as the chin wing could provide a better correction especially for bi-gonial and occlusal angles.

[Mandibular asymmetry: determination of a reliable skin measurement technique]. / Latéromandibulie : détermination d'une mesure cutanée fiable.

INTRODUCTION: Clinical measurements in the frontal view underevaluate chin deviation in mandibular asymmetry. The aim of this descriptive study is to search for a reliable method of measuring deviant chins using a facial X-ray as reference. MATERIAL AND METHOD: Seventy patients with mandibular asymmetry who had consulted a maxillofacial surgeon were systematically included. Age, sex, cephalometric characteristics, reasons for patient consultation and type of surgery were collected. Two cephalometric methods were tested with respect to the medial sagittal plane (PSM) to compare the assessment of mandibular asymmetry on soft tissue and by cephalometry. RESULTS: On average, the patients selected were young (26 years +/- 9), women (75% of cases), presented open bite (average FMA: 28° +/- 8°), a skeletal class III tendency, a left-side shift of the chin (63% of cases). They consulted for both aesthetic and functional reasons (51% of cases) and required bimaxillary surgery (66% of cases). Comparison between the photographic angle (formed by the PSM and the line passing through the nasion and reaching the chin point) and the radiographic angle (formed by the PSM and the line passing through the Crista Galli process and the bony chin point angle) showed no significant difference (p = 0.937) and is thus reliable.