Stability after Mandibular Advancement using Bilateral Sagittal Split Osteotomy

The bilateral sagittal split osteotomy (BSSO) of the mandible is performed to improve function and aesthetics if skeletal discrepancy between dental arches are severe. The aim of this retrospective study was to evaluate skeletal stability after surgical advancement of the mandible with BSSO. Inclusion criterion was patients with Angle Class II occlusion undergoing mandibular advancement with BSSO between 2006 and 2015. For analysis of skeletal stability, cephalometric measurements were performed on lateral cephalograms preoperatively, direct postoperatively and 18 months postoperatively. 39 patients were analysed preoperatively (T0) and direct postoperatively (T1). 22 patients were analysed at the 18 months’ postoperative follow-up (T2). The mandibular position in the facial skeleton was analysed with SNB, ANB, ML/NSL and Wits appraisal. The cephalometric analysis showed statistically significant differences between T1 and T2 (paired t-test, p < 0.05). The analysis on subgroup level showed a statistically significant difference in SNB angle and in Wits appraisal within groups with medium and large magnitude of surgical movement and with patients > 25 years. This indicates a possible minor skeletal relapse, therefore these patients might require safety measures to minimize the risk of relapse. The results showed minor skeletal changes between T1 and T2, and this study indicates that the BSSO generates an adequate skeletal stability.