Abstract: Objective To evaluate the application effect of lag screw technique in alveolar ridge bone block grafting. Methods Thirty-six patients with Terheyden 2/4 type severe bone deficiency in the horizontal direction requiring implant restoration. 15 males and 21 females, aged 18~54 years, with the narrowest alveolar ridge width in the range of 1.2 mm~4.0 mm. Using lag screw technique, autologous bone block is fixed to the graft area, surrounded by deproteinized bovine bone mineral（Bio-Oss）, covered with acellular porcine pericardium （BONANGA）. Reduce tension and suture wounds. Observe and record the stability of the bone block, including the occurrence of bone fragment splitting, rotation and displacement, as well as postoperative wound healing. CBCT was used to measure the width and height of the alveolar ridge before surgery, immediately after surgery, 3 months and 6 months after surgery. SPSS 21.0 was used for statistical analysis of the measurement data. Results All the 36 cases of autologous bone grafts were stable, and there was no bone fragment splitting. The wound healed well in the bone graft area. In 2 cases, the wound of the chin donor site was dehiscent during the healing process, and gradually healed after dressing was changed, and the rest did not have adverse reactions requiring special treatment. The preoperative average buccolingual alveolar width was（4.20±1.10）mm, Immediately after the operation, 3 months and 6 months after the operation, the average buccolingual alveolar width was（9.60±1.28）mm, （8.81±1.36）mm and （8.25±1.28）mm, which were significantly different from those before the operation. Conclusion The application of lag screw technique in alveolar ridge bone block grafts is simple and effective, which is worthy of clinical promotion and application.

Key words: Lag screw, Alveolar bone grafting, Dental implants, Alveolar ridge augmentation