Ref.: MmeCo14-003

Do titanium biomaterials get immediately and entirely repassivated?

Apresentador: Ricardo Manuel Souto

Autores (Instituição): Souto, R.M.(Universidad de La Laguna); Burstein, G.T.(University of Cambridge); Asserghine, A.(University of Illinois at Urbana?Champaign); Pérez, J.I.(Universidad de La Laguna);

Resumo:
Titanium and its alloys have been widely used in clinical applications because of their biocompatibility and exceptional chemical inertness, in addition to their outstanding osseointegration characteristics. They are well known for forming a robust protective film on the surface that provides high corrosion resistance to the surrounding environment. The film reforms very quickly if removed or mechanically damaged, and is chemically stable in physiological environments. Despite the ability of the passive film to adhere and reform, titanium corrosion products (e.g. in the form of submicron particles) are often observed in tissues adjacent to implant prosthesis. Although titanium appears to be tolerated in the body in trace amounts, the long-term accumulation and the non-excretion of titanium remains a biological concern. Possible harmful effects of other alloying elements have also been described in the case of its alloys. This contribution describes our work using high-resolution microelectrochemical techniques to study the passive regime and eventual metal dissolution in titanium and its biomaterial-grade alloys. Evidence has been collected of very localised and minute passivity breakdown events occurring well below the material’s pitting potentials, as well as the occurrence of electron transfer reactions despite the dielectric behaviour of the passive oxide layers. Thus, further optimizations are required for their upcoming applications.