The stability of bilateral sagittal ramus osteotomy and vertical ramus osteotomy after bimaxillary correction of class III malocclusion

IntroductionThe purpose of this retrospective cephalometric study was to compare the stability of bilateral sagittal split osteotomy (BSSO) with extra-oral vertical ramus osteotomy (VRO) after correction of class III malocclusion by means of bimaxillary orthognathic surgery.MethodsThe sample comprised 51 consecutively treated patients, 38 females and 13 males, with a mean age of 19.1 years. All had a one-piece Le Fort I osteotomy with maxillary advancement and mandibular setback. VRO was performed in 30 cases, and BSSO was performed in 21 cases. Lateral cephalograms were obtained before surgery, within 1 week of surgery and 1 year after surgery.ResultsThe mean forward movement of the maxilla was 5.6 mm in both groups (p < 0.001). The mean horizontal surgical change in the VRO group was 4.4 mm (p < 0.001), and in the BSSO group it was 5.4 mm (p < 0.001). In the VRO group, the horizontal relapse was 1.2 mm (p < 0.001), and in the BSSO group, it was 1.4 mm (p < 0.001).ConclusionThere was no difference in the stability between the BSSO and VRO groups. The average relapse in the whole sample was 26% of the surgical movement.