Journal of implantology and applied sciences ISSN:2765-7833(Print) 2765-7841(Online) 대한구강악안면임플란트학회지

Immediate implant placement in a fresh extraction socket is considered a predictable and acceptable procedure. The advantage of this procedure is reducing rehabilitation time and preserving alveolar ridge. However, the incongruity of shape between dental implant and extraction socket wall may inevitably cause coronal gaps which will affect negatively to the osseointegration of dental implants. There have been many studies to resolve these gaps including usage of barrier membrane or bone graft materials. The aim of the study is to evaluate the effect of new alloplastic material, biphasic calcium phosphate on healing of surgically created circumferential gap defect in dogs at 12 weeks after placement. 4 mongrel dogs were used in this study. All premolars and first molar on both sides of the mandible were extracted. After 8 weeks of healing, cylindrical shaped gap defects which are 2 mm width and 5 mm depth were surgically prepared with customized stepped drills. Dental implant placement and biphasic calcium phosphate (OSTEONⓇ) grafting was performed on the defect of test group. Dental implant without bone graft was placed for the control group. After 12 weeks of healing, block biopsies of each implant site were dissected and processed for ground sectioning to evaluate histologically and analyze histometrically. At 12 weeks, there was limited new bone formation and incomplete defect closure on the defect of control group. Connective tissue and epithelial migration was detected on the defect. In test group, the defect was filled with matured new bone and residual graft material. Marginal gap was filled with graft material without any soft tissue engaging. Active bone formation around the graft particles was found. Significantly greater bone to implant contact area was shown at the test group compared to the control group and greater bone density was also found at the test site. Withe the limit of this study, biphasic calcium phosphate seemed to have beneficial effects on the healing of surgically created circumferential gap defect around implant in dog model at 12 weeks period.