Intraoral oblique sagittal splitting osteotomy for mandibular prognathism with or without anterior openbite

3. Longitudinal observation with postero-anterior cephalograms

Abstract

The position of the proximal segments of mandible in 30 patients following intraoral oblique sagittal splitting osteotomy were longitudinally analysed with postero-anterior cephalograms at least 6 months after surgery.The subjects consisted of 15 cases of mandibular prognathism alone and 15 cases of mandibular prognathism with anterior openbite.
Comparing pre- with immediate post-operative positon, the proximal segment shifted 2.5mm laterally in the pronathism alone cases.In the cases of prognathism with anterior openbite, the segment also moved 1.3mm laterally.During intermaxillary fixation, the segment shifted medially and approached the preoperative position in both groups.The amout of return was 1.0mm in prognathism alone cases and O.5mm in combined cases.
After taking off the fixation, the proximal segments of both groups have been physioloically stable in the position at the fixation release.