Mechanical properties and biocompatibility of titanium with a high oxygen concentration for dental implants

In order to improve the strength of commercially pure Ti (CP-Ti) for oral implants, the high oxygen content Ti (HOC-Ti) was prepared via powder metallurgy. Its composition and mechanical properties were then characterized. After surface treatment by sandblasting and acid etching (SLA), the surface morphology, wettability and roughness of the HOC-Ti and CP-Ti sample were examined. In an in vitro test that followed an evaluation of the protein adsorption capacity of HOC-Ti, the mouse preosteoblast cells were inoculated onto the specimens to evaluate their biocompatibility, in comparison with those of CP-Ti. The oxygen concentration of the HOC-Ti increased to 0.62 wt%, which is higher than the 0.26 wt% of the CP-Ti, while their compositions and microstructures were very similar. The tensile and compressive yield strength of the HOC-Ti (800 MPa) was improved significantly in comparison to that of the CP-Ti (530 MPa). After surface treatment, a unique structure of micropores with a diameter of 380 nm was observed on the entire surface of the HOC-Ti that facilitates cell adhesion and proliferation. The wettability of the HOC-Ti was obviously superior (p < 0.05). The in vitro study showed that the MC3T3-E1 cells inoculated on the surface of HOC-Ti exhibited a homogeneous microstructure, and the viability was higher than that of the control group on days 4 and 7 (p < 0.05). In addition, the number and differentiation activity of cells that adhered to the surface of the HOC-Ti increased significantly on day 7 (p < 0.05). The experimental results showed that, in view of its mechanical properties and biocompatibility, HOC-Ti is superior to CP-Ti and is promising for oral implant applications.