BIODETERIORATION OF METALLIC BIOMATERIALS INFLUENCE OF THE COMPOSITION OF THE BIOLOGICAL MEDIA

摘要: Metallic biomaterials used in medicine and dentistry are habitually in contact with biological fluids and interact with them. As a result of these interactions biodeterioration occurs involving corrosion, tarnish and/or pigmentation processes. These processes affect the functionality, resistance and aesthetic aspects and may also involve metal ions release at higher concentrations than the biocompatible limits. The degree of the interactions depends on the substratum and on the composition of the biological medium. The electrochemical behaviour of biomaterials is frequently analysed in vitro. Unfortunately, the composition of the synthetic solutions used in the analysis by the different authors is often notoriously different. Thus, comparisons of the results obtained by different researchers are commonly difficult. The aim of this chapter is to summarize the studies made in our laboratory in relation to the effect of the individual components of the synthetic solutions that simulate the biological media composition on the biodeterioration processes. The influence of the presence of cells and bacteria and the surface properties of the biomaterial on the electrochemical behaviour of the metal is also analysed. Aluminium, copper and silver were selected as non-noble labile substrata because they are frequently present in metallic biomaterials. Titanium was chosen as a biocompatible and corrosion resistant biomaterial. Potentiostatic and potentiodynamic electrochemical techniques and open circuit potential measurements are reported, complemented with surface analysis, optical and scanning electron microscopy. It could be concluded that the corrosion …