Abstract: PURPOSE: This randomized controlled trial was aimed to evaluate the effect of autogenous bone grafting in situ for regeneration of periodontal osseous defect distal to the M2 compared with non-grafting after removal of impacted M3. METHODS: A total of 60 sites in 51 adult patients were enrolled and randomly assigned to the control group or experimental group. In both groups the M3 was extracted using a piezosurgical device, and the distal root surface of M2 was scaled and root planned. In addition, the removed alveolar bone was grinded to particles and grafted to the distal osseous defect of M2 in the experimental group. The primary outcome variable was the osseous defect depth (ODD), the secondary outcome variables were pocket probing depth (PD) and clinical attachment level (CAL) on the disto-buccal aspect of M2 during a 12-month follow-up period. Postoperative symptom at 7-day and adverse events were also recorded and analyzed using SPSS 17.0 software package. RESULTS: Six and 12 months after surgery, there was statistically significant bone fill in both groups (P<0.01). Moreover, ODD and CAL in the experimental group were significantly lower than in the control group at each postoperative re-entry(P<0.01). Postoperative symptom was more severe in the experimental group than in the control group, but the difference was not significant (P>0.05). CONCLUSIONS: The RESULTS demonstrated that scaling and root planning was beneficial to periodontal healing of M2 after impacted M3 extraction. Autogenous bone grafting for the treatment of osseous defects distal to M2 was safe and more effective than periodontal treatment alone.

Key words: Impacted mandibular third molar, Bone regeneration, Periodontal bone loss, Randomized controlled trial