BACKGROUND:Titanium and titanium-coated materials are widely used in the field of oral implantology,but there are still phenomena such as peri-implantitis,implant loss and loosening.Therefore,the surface modification of pure titanium has become a hot topic in oral medicine research. OBJECTIVE:To investigate the physical and osteogenic properties of hydroxyapatite-graphene oxide composite coating on titanium surface. METHODS:Hydroxyapatite-graphene oxide composite coatings were prepared on the titanium surface by electrodeposition at voltages of 10,30,and 50 V.The micromorphology and hydrophilic properties of the coatings were characterized,and the composite coatings prepared under the optimal voltage conditions were screened for animal experiments.Fifty-four SD rats were selected to prepare defects of 2 mm in diameter and 7 mm in depth on the femoral head of both hind limbs,and were randomly divided into 3 groups with 18 rats in each group:no titanium material was implanted in the blank group;pure titanium material was implanted in the pure titanium group,and coated titanium material loaded with hydroxyapatite-graphene oxide composite coating was implanted in the coated group.The osteogenesis effect was observed by X-ray,Micro-CT scan,and pathological section staining at 4,8,and 12 weeks after implantation. RESULTS AND CONCLUSION:(1)Under scanning electron microscopy,when the voltage was 10 V,there were a lot of cracks and clumps in the coating.When the voltage rose to 30 V,there were still some small clumps in the coating,but the overall uniformity was relatively flat.When the voltage was 50 V,the coating was more evenly distributed and cracks and spots were reduced.The hydrophilicity of the composite coating prepared at 50 V voltage was the best.In summary,the composite coating material prepared at 50 V voltage was selected in animal experiments.(2)The X-ray film showed that the implant position was relatively fixed,and no serious postoperative inflammation occurred.The results of Micro-CT scan showed that the new bone formation rate and bone formation volume on the implant surface of the coated group were better than those of the pure titanium group(P<0.001).The results of Micro-CT scan were further confirmed by hematoxylin-eosin staining and Masson staining in pathological sections.Immunohistochemical staining of pathological sections showed that the expressions of osteopontin and bone morphogenetic protein 2 in the pure titanium group were higher than those in the blank group at week 12 after implantation(P<0.001),and those in the coated group were higher than those in the pure titanium group at week 12 after implantation(P<0.001).(3)The results show that the hydroxyapatite-graphene oxide composite coating material has good physical and osteogenic properties.