Characterization of labiomandibular movements induced after isolated LeFort I osteotomy in the surgical management of class III malocclusion.

INTRODUCTION: Maxillary surgery alone can be proposed for the surgical management of class III malocclusion, but anticipating outcomes for the labiomental muscle complex is challenging due to the mandibular autorotation phenomenon. The objective of this study was to quantify the mandibular and labiomental movements induced by maxillary osteotomy alone in the management of class III malocclusion according to different clinical and surgical variables. METHODS: The post-operative changes in mandibular and labiomental shapes were studied by geometric morphometry from the pre- and post-operative lateral cephalometric radiograph of 25 patients. The explanatory variables tested were maxillary advancement, maxillary rotation, and divergence. RESULTS: Soft tissues repositioning are different from postoperative mandibular repositioning after maxillary osteotomy. Neuromuscular adjustments of mandible depend on divergence and the maxillary rotation. Labiomental response only depends on divergence. CONCLUSION: The surgical procedure does not have the same bone-related and musculocutaneous effects on patients with the same class III malocclusion. It is therefore essential for surgeons to understand the effects of their procedure on musculocutaneous tissues in order to best anticipate post-operative outcomes.

[Etiopathogenic and clinical aspects of asymmetry]. / Approche étiopathogénique et clinique des asymétries.

Complex dysmorphies, asymmetries can affect the various elements of the stomatognathic system: cranial base, maxilla, mandible, musculature and dental arches, in the three dimensions of space. Their etiopathogenesis, as well as their clinical forms, vary considerably. Dysembryopathies, growth disorders, TMJ damages, postural or functional disorders and dental anomalies can create, according to their severity and their moment of appearance, severe or minor facial asymmetries, or asymmetries of the arches. An exo- and endobuccal clinical examination endeavors to specify the localization and the severity of the damage, and to evaluate the importance of the possible alveolar compensations. Consolidated by additional examinations, it enables the clinician to differentiate the various forms of asymmetries.