Titanium is used in dentistry in many applications: crowns, fixed and removable partial dentures, suprastructures and implants. In these functions, titanium may get in contact with prophylactic agents such as toothpastes and gels that contain fluorides.
Dental copper-based alloys have become popular for crowns and fix prostheses in some countries, mostly because they have a gold-like appearance and are much less expensive than gold alloys. The accessibility of copper-based alloys is increasing and they are now available in Western Europe and US, but the discussion of their biocompatibility continues. It has been advocated that the alloys should not be generally used in dentistry.
The aim of this investigation was to:
• study the effects of fluorides on surfaces of titanium cp-II in saline solutions with different pF and pH using electrochemical techniques
• study various aspects of corrosion of a copper-aluminium alloy in saline and artificial saliva using electrochemical techniques.
The electrochemical techniques used were recording of open circuit potential, anodic polarisation and electrochemical impedance. Inductively coupled plasma spectroscopy of lactic acid saline extracts was also used.
The results clearly show that titanium does not maintain its passivating properties in an acidic environment containing fluorides and that the copper-based alloy is an active corrosion state in the chloride containing electrolyte solutions; either saline or artificial saliva.