Stability of the mandible after surgical correction of skeletal class III malocclusion in 50 patients.

Fifty cases of skeletal Class III malocclusion were analyzed by the tracings of presurgical and postsurgical cephalograms to evaluate the stability of the mandible a year after surgery. In 33 patients, the curved oblique osteotomy in the ascending ramus was used; the correction was made in the mandibular body for 17 patients by either the rectangular osteotomy or the sliding osteotomy. Minimal relapse was observed in all three procedures, with the least amount occurring after mandibular body ostectomy or osteotomy. The results were considered to be due to careful determination of the correct time for surgery in each patient to avoid skeletal relapse resulting in continued mandibular growth, prompt osseous healing at the surgical sites by providing close and tight bony contact between the segments, elimination of the effect of the major muscles of mastication, minimum alteration in the position of the posterior segment and trimming of the margin of the anterior segment to form a proper gonial angle, and a stable occlusion with maximum intercuspation and an adequate overbite. In addition, preoperative orthodontic treatment and extraoral traction of the mandible by chin cups were considered effective means to stabilize the post-operative occlusion.