Long-term follow-up of Class II malocclusion treated with bilateral sagittal split osteotomy: a retrospective study with 6–19 years of follow-up

This retrospective cohort study was performed to investigate the long-term skeletal, dental, and aesthetic stability, and patient satisfaction, following mandibular advancement with bilateral sagittal split osteotomy (BSSO) in skeletal Class II malocclusion patients. The follow-up period ranged from 6 to 19 years (mean 11.9 years), longer than in many previous studies. Twenty-nine patients (18 female, 11 male) who underwent mandibular advancement with rigid internal fixation between 2004 and 2017 were included. Lateral cephalometric radiographs from four time points were analysed: pre-surgery (T1), post-surgery (T2), 6-12 months post-surgery (T3), and long-term follow-up (T4). Patient satisfaction with the treatment outcome was assessed using the Orthognathic Quality of Life Questionnaire (OQLQ, Swedish version). The mean mandibular advancement was 5.53 ± 1.91 mm. Long-term follow-up revealed stable skeletal and dental outcomes, with no significant relapse in SNB, ANB, overjet, or overbite between T3 and T4. Soft tissue changes (T3-T4) for lower lip to E-line distance (mean -3.86 mm to -4.74 mm) and N'-Sn-Pog' angle (mean 159.91-162.11°) were statistically significant (P < 0.001) but not clinically relevant. Neurosensory disturbances were present in 21 patients after the surgery (72%), and these persisted in 13 at long-term follow-up (45%). Despite this, OQLQ scores indicated high patient satisfaction (mean 12.6, range 0-70), with minimal functional problems and improved oral health-related quality of life. These findings demonstrate the long-term skeletal and dental stability of BSSO with rigid fixation, as well as its effectiveness in achieving high patient satisfaction in the correction of skeletal Class II malocclusion.