title: [The effect of fluoride on electrochemical corrosion of the dental pure titanium before and after adhesion of Streptococcus mutans].
abstract: OBJECTIVE
  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 (R(ct)), corrosion potential (E(corr)), pitting breakdown potential (E(b)), and the difference between E(corr) and E(b) representing the "pseudo-passivation" (ΔE) 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 R(ct), Ecorr, E(b), and ΔE 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.
authors.affiliation: Department of Stomatology, Putuo Hospital Affiliated to Shanghai University of Traditional Chinese Medicine. Shanghai 200062, China. E-mail:gl2027@163.com.
authors.forename: Li
authors.initials: L
authors.lastname: Geng
authors.affiliation: Department of Prosthodontics, School of Stomatology, Tongji University. Shanghai 200072, China.
authors.forename: Guang-yan
authors.initials: GY
authors.lastname: Qiao
authors.affiliation: Department of Prosthodontics, School of Stomatology, Tongji University. Shanghai 200072, China.
authors.forename: Kai-ka
authors.initials: KK
authors.lastname: Gu
mesh_terms: D003343:Corrosion; D058266:Dielectric Spectroscopy; D005459:Fluorides / Q000737:chemistry*; D008422:Materials Testing; D010710:Phosphates; D012464:Saliva, Artificial; D013295:Streptococcus mutans / Q000502:physiology*; D013499:Surface Properties; D014025:Titanium / Q000737:chemistry*
chemical_list: D010710:Phosphates; D012464:Saliva, Artificial; C012980:fluorophosphate; D014025:Titanium; D005459:Fluorides