Objective: To investigate the factors responsible for the skeletal relapse after correction of mandibular prognathism by BSSRO.
Methods: The skeletal and dental changes before and after the surgery were analysed by cephalometrics, The factors that might be responsible for the skeletal relapse were evaluated using multiple linear and partial correlation analysis.
Results: The changes of NP-FH angle at follow up had a significant correlation with MP-FHT4-3 angle, the duration of presurgical orthodontics and the observation period after surgery(r = -0.568, -0.406, -0.400, P < 0.01-0.05).
Conclusion: The skeletal relapse following BSSRO was limited. The stability was related to the period of presurgical orthodontics and the mandibular rotation after the surgery.