Fabrication of calcium phosphate films for coating on titanium substrates heated up to 773 K by RF magnetron sputtering and their evaluations

Calcium phosphate films were fabricated on titanium substrates heated up to 773 K using radiofrequency (RF) magnetron sputtering. The deposition rate, phase and preferred orientation of the calcium phosphate films were studied. Immersion tests for the films were conducted using Hanks' solution and PBS(-), and the surface reactions on the specimens coated with the calcium phosphate films were investigated. The bonding strength between the coating films and the titanium substrates before and after the immersion tests was evaluated; the bonding strength decreased after the immersion tests. The alkaline phosphatase (ALP) activity of SaOS-2 cells on a titanium plate coated with a calcium phosphate film was examined by conducting a culture test. Calcium phosphate coating increased the ALP activity of SaOS-2 cells cultured for 3 and 7 days. Titanium cylinders were coated with an amorphous calcium phosphate film and implanted into the mandibles of beagle dogs. An increase in the extent of bone-implant contact for the coated titanium cylinders was confirmed 8 to 12 weeks after implantation and compared with the case for uncoated titanium cylinders.