Presence of mandibular third molars during bilateral sagittal split osteotomy increases the possibility of bad split but not the risk of other post-operative complications.

Timing of third molar removal in relation to bilateral sagittal split osteotomy (BSSO) is controversial, especially with regard to post-operative complications. We investigated the influence of mandibular third molar presence on complications after BSSO with sagittal splitters and separators, by a retrospective record review of 251 patients (502 surgical sites). Mandibular third molars were present during surgery at 169 sites and removed at least 6 months preoperatively in 333 sites. Bad splits occurred at 3.0 % (5/169) and 1.5% (5/333) of the respective sites. Presence of mandibular third molars significantly increased the risk of bad splits (OR 1.08, CI 1.02-1.13, p < 0.01). The mean incidences of permanent neurosensory disturbances, post-operative infection, and symptomatic removal of the osteosynthesis material were 5.4% (OR, 0.89; 95% CI, 0.79-1.00; p = 0.06), 8.2% (OR, 1.09; 95% CI, 0.99-1.20; p = 0.63), and 3.4% (OR, 0.97; 95% CI, .92-1.03; p = 0.35) per site, respectively, without a significant influence of mandibular third molar status. In conclusion, the presence of mandibular third molars during surgery increases the possibility of bad split but does not affect the risk of other complications. Therefore, third molars can be removed concomitantly with BSSO using sagittal splitters and separators.