Management of mandibular third molar extraction sites to prevent periodontal defects

Persistent periodontal defects on the distal aspect of the mandibular second molar (M2) is a reported complication of mandibular third molar (M3) extraction. The purpose of this study was to measure the efficacy of demineralized bone powder (DBP) or guided-tissue regeneration therapy (GTR therapy) in preventing periodontal defects on the distal aspect of the M2 following M3 extraction.

We implemented a single-blind, randomized, controlled clinical trial composed of a sample of subjects > or = 26 years of age who required extraction of bilateral M3s. The primary predictor variable was treatment group. Each subject was randomly assigned to receive either DBP or GTR therapy. Within subjects, 1 M3 site was randomly selected to be the experimental site and the opposite M3 served as a control and was permitted to heal without intervention. The primary outcome variable was the change in attachment levels (AL) and probing depths (PD) on the disto-buccal aspect of M2 between T 0 (immediate preoperatively) and T 4 (26 weeks postoperatively). Appropriate sample size estimates, descriptive, bivariate, and multivariate statistics were computed.

Twelve subjects in the DBP group and 12 subjects in the GTR-therapy group completed the study. For both treatment and control sites, between T 0 and T 4, there were statistically significant improvements in AL (> or = 2.2 mm; P <.001) and PD (> or = 2.6 mm; P <.001). Within-subjects comparisons showed no significant differences in AL or PD between treatment and control M3 sites ( P > or =.3) at T 0 or T 4.

The results of this study suggest that attachment levels and probing depths improve after M3 removal. In this sample, DBP or GTR therapy did not offer predictable benefit over no treatment.