Abstract: PURPOSE: To investigate the effect of fluoride on electrochemical corrosion of the dental pure titanium before and after adhesion of Streptococcus mutans. METHODS: The dental pure titanium specimens were tested by electrochemical measurement system including electrochemical impedance spectroscopy (EIS) and potentiodynamic polarization curve (PD) methods in artificial saliva with 0 g/L and 1.0 g/L sodium fluoride before and after dipped into culture medium with Streptococcus mutans for 24 h. The corrosion parameters, including the polarization resistance (Rct), corrosion potential (Ecorr), pitting breakdown potential (Eb), and the difference between Ecorr and Eb representing the “pseudo-passivation” (△E) obtained from the electrochemical tests were used to evaluate the corrosion resistance of dental pure titanium. The data were statistically analyzed by 2×2 factorial statistical analysis to examine the effect of sodium fluoride and adhesion of Streptococcus mutans using SPSS 12.0 software package. RESULTS: The results showed that the corrosion parameters including Rct, Ecorr, Eb, and △E of pure titanium had significant difference between before and after adhesion of Streptococcus mutans in the same solution(P<0.05), and in artificial saliva with 0 g/L and 1.0 g/L sodium fluoride(P<0.05). CONCLUSIONS: The dental pure titanium was prone to corrosion in artificial saliva with sodium fluoride. The corrosion resistance of pure titanium decreased distinctly after immersed in culture medium with Streptococcus mutans.

Key words: Fluoride ions, Dental pure titanium, Corrosion resistance, Streptococcus mutans, Adhesion, Fluorine