Sagittal split advancement osteotomy: comparison of the tendency to relapse after two different methods of rigid fixation.

Mandibular advancement was studied in 32 patients with mandibular retrognathia in whom the only intervention was in the mandible. Fifteen patients were treated with fixation by lag screws and 17 with monocortical miniplates. Lateral radiographs were taken preoperatively, postoperatively, 2 months postoperatively, and 1.5 years postoperatively, and mandibular movement analysed. All patients healed uneventfully. Cephalometric analysis of lateral radiographs showed no significant differences between the two groups in skeletal relapse during any of the control periods up to 18 months. Mandibular advancement for treatment of mandibular retrognathia using rigid fixation with either lag screws or miniplates was reproducable with only minor skeletal relapse.