Complications of the mandibular sagittal split ramus osteotomy associated with the presence or absence of third molars.

PURPOSE

This study compared the number of unfavorable fractures after sagittal split osteotomies (SSOs) of the mandible when third molars were present or absent.

PATIENTS AND METHODS

The treatment records of 262 patients (500 SSOs) were retrospectively evaluated. Group 1 consisted of 250 SSOs and concomitant removal of impacted mandibular third molars and group 2 consisted of 250 SSOs with absence of third molars. A modified SSO technique with inferior border cuts was used on all patients, and the third molars, when present, were removed after separation of the proximal and distal segments. Rigid fixation was applied using bicortical bone screws. Bone plates with monocortical screws were additionally used to secure the free bony segments of the proximal segment in cases with unfavorable fracture.

RESULTS

There were 11 (2.2%) unfavorable fractures in 500 SSO procedures. The incidence of unfavorable splits was 3.2% in group 1 and 1.2 % in group 2. In group 1, all fractures occurred in teenagers, with 7 of 8 fractures extending through the extraction socket in the distal segment. Six of the 8 fractures were associated with completely impacted third molars, and 2 involved partially impacted teeth. All 3 fractures in group 2 occurred in the proximal segment. No significant difference was seen in the amount of relapse in patients with unfavorable or favorable splits.

CONCLUSIONS

The occurrence of unfavorable splits is uncommon when using a modification of the SSO that includes an inferior border osteotomy. Although more unfavorable fractures occurred in teenage patients with third molars, this had no impact on the stability of the final result.