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

The purpose of this study was to evaluate early bone healing process histologically at the defect gap between anodized implant and adjacent marginal bone, and to compare with the result of non-defect site, in case of immediate implant placement in the simulated extraction socket. Two anodized implants with 3.3mm diameter, 7.0mm length were inserted in right or left tibia of a rabbit, which sites were selected randomly. Total 48 screw-shaped titanium implants with anodized surface (Warantec, Seoul, Korea) were inserted in rabbit tibia. Before implants insertion, artificial bone defects(2×2×5mm) were made adjacent to distal implant site. Implants inserted in non-defect sites were control group and implants inserted in defect sites were experimental group. At 1, 2, 3, 7 weeks later, 6 rabbits were sacrificed at each stage and undecalcified sectional slides were made for histologic evaluation. With light microscope, histologic processes of bone healing were observed and compared. At the first week of experimental group, new bone formation was initiated from the endosteum of the marginal bone near the defect site and woven bone approached into the defect site gradually. But the quantity was small. And solitary bone formation at implant surface was observed. At second week, new bone formation was very broad and rapid, and active bone healing response was observed. This appearance continued to third week. At second and third week, though the bone density was low, the bone formation area of experimental group was larger than that of control group. At seventh week, new bone formation was disappeared and lamellar bonewas observed, and the gap of cortical bone was healed with bone-bridge in 3 specimens among 6. Although, the covering cortical bones of defects of experimental group were thinner and less mature than those of control group, defects were covered and filled with bone and bone tissue, that means it could be concluded that defects were healed. But, in cases of other 3 specimens, defect gaps were remained. Considering this result, 2mm marginal defect might not be healed with new bone, so, implants installation without any additional therapy -e.g) bone graft, GBR-would not be safe.