Bio-tribo-electrochemical degradation of titanium-based materials for dental implants application

In the oral cavity titanium dental implants are subjected to a complex degradation process involving chemical/electrochemical, mechanical and microbiological components. The chemical elements of saliva such as chloride, fluoride and H ions, changes in pH and temperature are promoters of the chemical degradation of implants named as corrosion. In addition to the chemical/electrochemical degradation process, titanium-based materials exhibit poor wear resistance and, thus, a synergism effect between the chemical and mechanical degradation processes known as tribocorrosion can occur. This mechanism of degradation becomes more complex by the presence of a structured community of microorganisms surrounded by an extracellular matrix called biofilm. Clinically, such degradation process may affect the biocompatibility and function of dental implants, or even exacerbate an inherent condition for failure of the rehabilitation treatment. Therefore, the aim of this presentation is to discuss the basic corrosion kinetics and tribocorrosion behavior of titanium dental implants into simulated oral environment. The roles of titanium material, surface treatments, saliva pH, infection (simulated by the presence of lipopolysaccharide), hyperglycemic condition and mastication on the electrochemical activity of titanium will be presented. The possible implications of corrosion on the lipopolysaccharide affinity and periodontopathogenic bacteria attachment will also be assessed.