Biological aspects of TiNi alloy surfaces

A review on biocompatibility of TiNi alloys and related surface properties is presented. TiNi alloys showed biocompatibility comparable to that of stainless steel in in vivo and to titanium and Co-Cr alloys in in vitro. The nature of good biocompatibility is related to the properties of TiNi surfaces which revealed the tendency to be covered with TiO2 based oxides with a little amount of Ni (0-5%) in them. Estimations of the concentrations of both alloy components in the biological media after exposure to autoclaved TiNi specimens indicate that release of metals may be biologically insignificant.