Nanoporous tantalum coated zirconia implant improves osseointegration

Zirconia has become a new dental implant material because of its excellent esthetics, biocompatibility, and minimal ion release. However, biological inertness of zirconia surface results in weak integration with bone tissue in the early stage of osseointegration. To enhance the early osseointegration of zirconia implant, a homogeneous nanoporous tantalum (TaNS) coating (~30 nm in diameter and 1 μm in length) with good adhesion strength was prepared on zirconia surface via magnetron sputtering combined with anodization. The roughness and hydrophilicity in ZrO₂/TaNS groups were significantly improved as compared to other groups. The protein adsorption, initial adhesion, spreading and proliferation of MC3T3-E1 cells were significantly enhanced in ZrO₂/TaNS group as compared to ZrO₂ and ZrO₂/Ta group. Moreover, the osteogenic differentiation of MC3T3-E1 cells was significantly improved in ZrO₂/TaNS groups than other groups by up-regulating the expression of the osteogenic-related genes (RunX2, ALP, COL-1, OSX, OCN and OPG). Histological analysis displayed that more newly regenerated bone was deposited around ZrO₂/TaNS group than other groups, and the bone-implant contact in ZrO₂/TaNS group was enhanced correspondingly. In conclusion, the TaNS coating with good adhesion strength can be successfully prepared on zirconia surface by magnetron sputtering combined with anodization. This novel coating will be a promising clinical application in improving osseointegration of the zirconia implant.