J Oral Implantol. 2010 Jun 14. [Epub ahead of print]
Abstract
Objectives: The effect of fluoride ion concentration on the corrosion behavior of Ti and Ti6Al4V implant alloys, when coupled with either metal/ceramic or all-ceramic superstructure, was examined by different electrochemical methods in artificial saliva solutions.
Materials and methods: Impedance measurements were conducted with excitation amplitude of 10mV and a working frequency ranging from 0.1-100 KHz which includes a-c impedance plots. The potential of the different tested electrodes in different test media under open circuit conditions was followed with time until a steady state was reached (OCP). Anodic polarization was done by immersion of the electrodes for 60 minutes in the test solution and then polarized anodically by + 0.5V to the open circuit potential for 30 min. The corrosion resistance measurements (Rp) for each tested electrode in different fluoride concentrations at OCP and after polarization, together with their potential difference after polarization, were recorded and tabulated.
Results: It was found that fluoride ions affect the corrosion behavior of Ti and Ti6Al4V implants, and the severity of the attack is dependent on the concentration of fluoride ions. A decrease in corrosion resistance rate was observed in neutral saliva solutions with high fluoride concentrations.
Conclusions: Increased fluoride concentration leads to a decrease in the corrosion resistance of all the couples. The presence of alumina in Ti6Al4V implants significantly decreases its ability to resist corrosion, and the difference in the type of superstructure had a significant effect on the corrosion resistance of the couple.
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