Mechanical properties, in vitro corrosion resistance and biocompatibility of metal injection molded Ti-12Mo alloy for dental applications

A biocompatible Ti-12Mo alloy was fabricated by metal injection moulding (MIM) using non-spherical titanium, molybdenum powders and a purposely designed binder. The density, microstructure and tensile properties were characterized. This was followed by a detailed assessment of its in vitro corrosion and biocompatibility performances, compared with that of two commonly used titanium-based materials extra low interstitial (ELI) Ti-6Al-4V and commercially pure (CP) titanium. The MIM-fabricated Ti-12Mo alloy can achieve a wide range of mechanical properties through controlling sintering process. Specimens sintered at 1400 degrees C are characterized by fairly uniform near-beta microstructure and high relative density of 97.6%, leading to the highest tensile strength of 845.3 +/- 21 MPa and elongation of 4.15 +/- 0.2% while the highest elastic modulus of 73.2 +/- 5.1 GPa. Owing to the formation of protective TiO2-MoO3 passive film, the MIM-fabricated Ti-12Mo alloy exhibits the highest corrosion resistance including the noblest corrosion potential, the lowest corrosion current density and the highest pitting potential in four different electrolytes. The in vitro cytotoxicity test suggests that the MIM-fabricated Ti-12Mo alloy displays no adverse effect on MC3T3-E1 cells with cytotoxicity ranking of 0 grade, which is nearly close to ELI Ti-6A1-4V or CP Ti. These properties together with its easy net-shape manufacturability make Ti-12Mo an attractive new dental implant alloy.