Changes in the lip-line in asymmetrical cases treated with isolated mandibular surgery.

OBJECTIVE: The aim of this study was to investigate changes in the lip-line in asymmetrical cases treated with mandibular osteotomy alone. DESIGN: Retrospective study. SETTING: Hiroshima University Institute of Biomedical & Health Sciences, Hiroshima, Japan METHODS: The subjects in this study consisted of 30 patients with an altered lip-line inclination who underwent isolated mandibular osteotomy (bilateral or unilateral sagittal split ramus osteotomy or intraoral vertical ramus osteotomy) as part of their surgical correction. Frontal cephalograms and facial photographs, taken at the first examination and after treatment, were used to measure changes in the inclination of the lip-line and cant of the occlusal plane, as well as the lateral deviations of hard and soft tissue Menton. RESULTS: Inclination of the lip-line after active treatment was significantly improved compared with that before treatment. Menton on the hard and soft tissues after active treatment also experienced a significant improvement compared with its position at first examination. CONCLUSIONS: One-jaw mandibular osteotomy is able to improve the inclination of the lip-line even in the presence of an occlusal cant. The inclination of the lip-line is corrected in association with sufficient lateral movements of Menton on the mandible.