This is a study of postoperative changes in the mandibular prognathism surgically corrected by sagittal split osteotomy (Obwegeser-Dal Pont method), using cephalometric analysis of 10 cases of long-term prognosis (comparing cases of 1 year with those of more than 10 years).
All cases had good occlusion and none had poor anterior occlusion due to some degree of relapse. The mean values of movement of 10 of the mandibular structure on lateral cephalograms 10 years after the operation tended to move slightly downwards and backwards. The axial inclination of the upper incisors tended to lean toward lingual, and that of the lower incisor tended to lean toward labial. 5 cases had a little back-ward movement of pog, 3 cases had a forward movement, and 2 cases had no movement. The greatest changes were observed in 2 cases with a 3.5mm relapse on pog, but maintained good occlusion. The axial inclinations of the incisors were quite varied but were not due to the movement of the mandibular structure. From this study, we concluded that sagittal split osteotomy (Obwegeser-Dal Pont method) was an excellent type of operation resulting in maintenance of good stability of mandibular structure and occlusion even after a long time (more than 10 years after the operation).
