Abstract: PURPOSE: To investigate early regenerated buccal bone remodeling following dental implant surgery with guided bone regeneration (GBR) in the esthetic area using bone xenografts. METHODS: From September 2015 to April 2016, 23 dental implants in the maxillary anterior region with simultaneous GBR using bone xenografts were included in the study. Cone-beam CT (CBCT) was acquired before operation, once the operation was finished and 6 months after surgery. Mucosal thickness (>2 mm or ≤2 mm), types of bone quality and different membranes used were also identified. The buccal bone width perpendicular to implant long axis was taken 2 mm below the implant shoulder, midpoint and apical point of implant body at 3 intervals: the mesio-distal midpoint of the implant and 1mm mesial and distal to the the midpoint. Standardized measurements were taken to record alveolar height, width and undercut depth from preoperative CBCT scans. The data were analyzed using SPSS 21.0 software package. RESULTS: Loss in width of augmented bone after 6 months of healing was (0.70±0.59) mm, (0.85±0.72) mm and (0.55±0.51) mm. Bone absorption rate was 23.07%, 18.53% and 12.97%, respectively. The variables "undercut" and "age" had significant influences on bone graft resorption (P<0.05). Multiple linear stepwise regression analysis revealed that only undercut was the independent risk factor for bone resorption among all variables (P<0.05). CONCLUSIONS: Early regenerated buccal bone remodeling occurs following dental implant surgery with GBR in the esthetic area. Undercut depth and patient age have a significant effect on graft resorption. Consequently, with deeper undercut, decreased resorption could be expected for regenerated buccal bone.

Key words: Guided bone regeneration, Dental implant, Regenerated buccal bone, Esthetic area, CBCT