Sagittal splitting osteotomy of the mandibular ramus (Obwegeser Dal-Pont method) was performed on 13 patients with mandibular prognathism. The periodical changes in the position of the temporomandibular joint (TMJ) after the operation were examined by Mento Vertex (M-V) and P-A cephalometric projection.
The results obtained were as follows.
1) In 9 patients received bilateral operation, the condylar angulation at M-V projection increased significantly soon after operation and then showed a tendency to decrease gradually.
2) In 3 patients received unilateral operation, the changes of the condylar angulation on the non-operated side (large bone segment side) were larger than ones the operated side.
3) In the cases with different distance bilatellaly of backward movement, the changes of the condylar angulation on small movement side showed a tendency to be larger than on large movement side.
4) There was no significant change of the distance between the rami ends after the operation, and after the removal of intermaxillary fixation.
5) The condylar angulation and the ramus inclination at P-A cephalometric projection showed no definite tendency.
6) There were no cases with symptomatic TMJ after the operation except for one case with temporarily clicking.
Consequentry, we could suggest that TMJ had a considerable capacity to adaptation significant adaptation capacity
