Prevention of Mandibular Third Molar Extraction-Associated Periodontal Defects: A Comparative Study

Background: Extraction of deep-impacted mandibular third molars may lead to periodontal defects at the distal surface of the adjacent second molar. The purpose of this study was to compare the ability of three regenerative approaches to prevent third molar extraction-related periodontal defects. Methods: Forty-five patients with bilateral osseous or soft tissue-impacted lower third molars were selected to participate in the study. Inclusion criteria were the presence of a pocket that was located distally to the mandibular second molar with a probing depth (PD) >= 7 mm and with a probing clinical attachment level (CAL) >= 6 mm. Ninety third molar impactions were used and were randomly assigned to three equal treatment groups (30 each): bovine porous bone mineral (BPBM) alone, BPBM plus collagen membrane (CM), and an untreated control group. Clinical and radiographic measurements were recorded at 3, 6, 9, 12, 18, 24, 36, 48, 60, and 72 months after the surgery. Results: BPBM or BPBM + CM resulted in a significant reduction in PD and gain in CAL compared to the control group at all time points. BPBM + CM had the best outcome for the prevention of a second-molar periodontal defect. Conclusion: The application of BPBM, with or without a collagen membrane, can be a viable and stable treatment to alleviate the periodontal defects that are often associated with impacted mandibular third molar extractions. J Periodontol 2009;80:389-396.