Autologous Dentine Graft Compared to Xenograft in Managing Periodontally Compromised Second Molar After Third Molar Removal

The goal of this study is to evaluate the efficacy of autologous dentin graft (ADG) in treating periodontal defects on the distal aspect of mandibular 2nd molar (M2) after surgical removal of impacted mandibular 3rd molar (M3) by improving periodontal and radiological outcomes when compared with a xenograft, which is commercially available. The main questions it aims to answer are: 1. How does the clinical efficacy of ADG compare to xenografts, regarding wound healing and periodontal parameters at the distal aspect of periodontally compromised mandibular M2 following impacted M3 extraction? 2. How does the radiological bone regeneration at ADG-grafted sites differ from that at xenograft-grafted sites? 3. How do the post-operative patient-reported outcomes at sites receiving ADG differ from those at sites receiving xenografts? Researchers will compare ADG to xenograft to see if ADG is more efficacious in managing periodontal defects on distal aspect of M2 after surgical removal of M3. Participants will 1. Undergo bilateral surgical removal of M3 under general anaesthesia 2. Receive ADG on test site and xenograft on contralateral control site 3. Come back for clinical assessments, wound healing assessments and radiographic assessments for 5 times after the surgery (2 weeks, 1 month, 3 months, 6 months and 12 months)