Objectives: To analyse skeletal and occlusal stability 3 years after bimaxillary surgery in high-angle skeletal Class II malocclusions: amount and direction of postoperative changes.
Methods: Thirty-one consecutively operated high-angle patients (22 females, 9 males) were monitored for 3 years after surgery (BSSO advancement and LeFort I). Cephalometric analysis was performed on the following occasions: one week before surgery, 1 week and 3 years after surgery. A coordinate system was constructed through sella, with x-axis drawn 7° clockwise to sella-nasion line and vertical axis passing through sella perpendicular to x-axis to measure surgical change and relapse.
Results: Mean horizontal relapse at B-point was 2.7 mm (35.7% of advancement). Of 24 subjects with more than 2 mm mandibular advancement, 14 had more than 2 mm horizontal relapse at B-point. In 13 subjects anterior maxilla was moved up more than 2 mm during surgery; relapse of more than 2 mm occurred in 6 of these. No significant relapse in overjet and overbite was observed.
Conclusions: After bimaxillary orthognathic surgery significant skeletal relapse occurred both horizontally and vertically, but wide individual variation was observed. Despite this skeletal relapse, the anterior occlusion remained stable in most patients.