Do titanium biomaterials get immediately and entirely repassivated? A perspective

Titanium and its alloys have been widely used for clinical applications because of their biocompatibility and exceptional chemical inertness, in addition to their outstanding osseointegration characteristics. They are well known to form a robust protective film on the surface that provides a high corrosion resistance with the surrounding environment. Although this passive state of titanium-based materials is often considered to be achieved very rapidly, even when damaged, and to be chemically stable in physiological environments, evidences of passivity breakdown and electron transfer reactions have been collected using high resolution microelectrochemical techniques. Thus, further optimizations are required for their forthcoming applications.