Usefulness of Post-Operative Maxillo-Mandibular Fixation on Stability of Sagittal Split Ramus Osteotomy (SSRO) for Mandibular Prognathism with or without Asymmetry

Objective: To assess the usefulness of maxillo-mandibular fixation (MMF), occlusal and skeletal stabilities were evaluated after bilateral sagittal splitting ramus osteotomy (BSSRO) with or without MMF to treat mandibular prognathism or asymmetry.Patients and Methods: Thirty-three cases who underwent surgical correction of mandibular prognathism or asymmetry were analyzed. The surgical procedure in all cases consisted of SSRO. The segments were fixed rigidly with titanium screws. A postoperative MMF was performed in 16 patients within one day of the SSRO. The MMF was placed for one week. The other 17 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 were then assessed.Results: Even without MMF, occlusion was guided to the planned position with soft elastics after surgery. Later than 1 month, occlusal and skeletal stability were satisfactory in both groups, and there was no correlation between the surgical results and post-operative MMF.Conclusion: MMF may not be necessary after a rigid fixation SSRO to treat mandibular prognathism or asymmetry, considering the risks of airway problems.