Mandibular stability after SSRO with or without postoperative maxillo-mandibular fixation for class III malocclusion

Objective: The objective of this study was to assess the usefulness of maxillo-mandibular fixation (MMF) from a viewpoint of skeletal and occlusal stability and to investigate the complications after surgery with and without MMF. Materials and methods: Twenty-seven patients who underwent surgical correction of class III malocclusion were analyzed. The surgical procedure in all cases consisted of a bilateral sagittal splitting ramus osteotomy (SSRO). The segments were then fixed rigidly with titanium screws. A postoperative MMF was performed in 13 patients within 1 day of the SSRO. The MMF lasted for 1 week. The other 14 patients were free to move their jaw on the day of the surgery and received occlusal guidance with elastics starting from the third postoperative day. Cephalograms were taken preoperatively, at 1 day postoperatively and at 1, 3, 6, 12, and 24 months after surgery. Skeletal and occlusal stabilities along with postoperative complications were then assessed. Results: Discomfort of the pharynx and postoperative pain was more severe in the MMF group. Even without MMF, occlusion was guided to the ideal position by an average of 5.3 days after surgery. Occlusal and skeletal stability was satisfactory in both groups, and there was no correlation between the surgical results and postoperative MMF. Conclusion: MMF may not be necessary after a rigid fixation SSRO, considering the risks of airway problems.