Factors affecting periodontal healing of the adjacent second molar after lower third molar surgery: a systematic review and meta-analysis.

OBJECTIVES: This systematic review and meta-analysis aim to evaluate the effect modifiers which may influence the periodontal healing of the adjacent second molar after lower third molar surgery. MATERIALS AND METHODS: Prospective studies including patients with third molars requiring removal, with at least 6 months follow-up were considered. Outcomes were periodontal probing depth (PPD) reduction, final PPD, clinical attachment level (CAL) change, final CAL, alveolar bone defect (ABD) reduction, and final ABD depth. Meta-regression was performed to identify factors. RESULTS: Fourteen studies were included in the quantitative synthesis. At 6 months, the PPD reduction was 1.06 mm (95% CI, 0.72 to 1.39 mm) and the remaining PPD was 3.81 mm (95% CI, 3.00 to 4.62 mm). Baseline PPD was strongly correlated with the remaining PPD at 6 months (p < 0.001, adjusted R(2) = 70.05%). CONCLUSIONS: Lower third molar surgery results in a modest reduction in PPD, CAL, and ABD; however, periodontal defects still remain at 6 months and beyond. Baseline PPD is strongly correlated with final PPD. While age is not shown to have effect on most of the periodontal parameters, a larger baseline PPD is more likely to manifest with increasing age and third molar surgery should be done before severe periodontitis occurs to avoid persistent periodontal defects. CLINICAL RELEVANCE: This study shows that lower third molar surgery results in modest improvement in periodontal parameters on adjacent second molars and identified factors such as baseline PPD which may affect the healing, which may guide the pre-, peri-, and post-operative management of lower third molar surgery.