Three-dimensional evaluation of positional change of the condyle after mandibular setback by means of bilateral sagittal split ramus osteotomy.

Abstract

The aim of this study was to evaluate condylar displacement in 3 dimensions by means of computed tomography after mandibular setback by sagittal split ramus osteotomy with rigid fixation and to compare these results with those from patients with mandibular advancement. Thirty Korean subjects with skeletal class III malocclusion who had undergone mandibular setback by sagittal split ramus osteotomy had computed tomographs taken. Tomographs were taken to evaluate the temporomandibular joint 1 month before and approximately 1 month after surgery. The position and angulation of the condyle were measured on axial or sagittal views. These measurements were analyzed to determine any correlations between the amount of mandibular movement and condylar displacement. The results of this study show that the condyle tends to move inferiorly and rotate inward on the axial view and backward on the sagittal view by a statistically significant amount. The positional change of the condyle after sagittal split ramus osteotomy was not correlated with the amount of the setback.