The purpose of this study was to compare the bone formation, maturation around HA-and titaniumcoated dental implants in dog. 5 hydroxyapatite coated IMZ implants and 5 titanium coated IMZ implants were placed into the previously extracted site in the mandible of 5 adults dogs. All dogs were injected intravenously Tetracycline, Alizalin red S, and Calcein for bone fluorescent labelling, After the experimental period of 16weeks, the dogs were sacrificed and tissue samples around the implants were obtained. Microscopic observations(ligth, polariged and fluorescence microscope), morphometric analysis, line profile with EPMA, and quantitative analysis for Ca,P, and Ti were performed. The results were as follows ; 1. Bone maturations around the implants were relatively lower than those of natural teeth. No significant differences in bone maturation and remodeling patterns were observed between the two implants groups. 2. Calcification of bone surrounding the implants was initiated in 8-11 weeks for HA-coated implants, while it took 11 weeks or more for Ti-coated implants. 3. Bone-to-implants contact ratio of 82.63% was recorded for HA-coated group and 72.25% for titanium coated group, with no significant difference between the two groups. 4. Bone around the implants exhibited reduced quantity of Ca and P in the $100{mu}m$ region relative to natural teeth, while the rest of the regions showed no statistical differences. No significant differences were found between the two implant groups. 5. There was a separation of HA layer from the implant core and subsequent infiltration of inflammatory cells into the resulting space in the HA-coated implants, and evidences of phagocytosis of HA particles by macrophages. Bone calcification was more rapid around HA-coated implants compared to titanium-coated implants, but HA coated implants did not show any significant differences either in the degree of calcification or the bone-to-implant contact ratio over Ti coated implants. HA coated implants may have complications associated with HA absorption and separation of HA layer from the implant core.