An Analysis of Mandibular Movements after Surgical Correction of Skeletal Class III Malocclusion

After surgical correction of skeletal class III malocclusions, their morphological and functional changes are observed. The functional changes of mandibular movements were analyzed from a threedimensional standpoint in this study. In regard to protrusion and lateral excursions, the range of motion of incisal and condylar points between intercuspal position and each occlusal border position was measured. In regard to maximum opening movement, amount of opening at incisal points and the range of motion of the condylar points was measured. The results were as follows 1. The range of motion between intercuspal position and each occlusal border position increased after surgery for both incisal and condylar points. This is due to the stylomandibular ligament restricting each occlusal border position which moves backward by sagittal splitting osteotomy and to the correction of occlusal interferance during protrusion before surgery. 2. The amount of maximum opening in maximum opening movement showed little change, but the range of motion of the condylar path showed an increasing tendency after surgery. It is suggested that there is close relationship between the change of the range of motion of condylar points and the morphological change of the ramus.