ABSTRACT
PURPOSE: This study was to investigate the effect of fluoride on adhesion of Streptococcus mutans and Streptococcus sanguis on the dental pure titanium surface. METHODS: The adhesion of Streptococcus mutans and Streptococcus sanguis on the dental pure titanium surface were examined by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay after soaked in artificial saliva containing different concentrations of sodium fluoride for 24 h. Then the surface roughness and surface morphology of the pure titanium were analyzed by atomic force microscope after bacterial adhesion experiments. The data was statistically analyzed by analysis of variance(ANOVA) with SPSS11.0 software package. RESULTS: After soaked in artificial saliva containing different concentrations of sodium fluoride for 24 h, the sequence of OD values showed the adhesion of Streptococcus mutans and Streptococcus sanguis on dental pure titanium surface was 0 g/L < 0.5 g/L < 1.0g/L < 2.0 g/L (P<0.05). In addition, the sequence of Ra values showed the surface roughness of pure titanium after bacterial adhesion experiments was 0 g/L < 0.5 g/L < 1.0g/L < 2.0 g/L (P<0.05). And the surface morphology of pure titanium was consistent with the changes of OD value and Ra value. CONCLUSIONS: The results of adhesion of Streptococcus mutans and Streptococcus sanguis, surface roughness and surface morphology reveal that fluoride aggravates the corrosion of pure titanium, increases the surface roughness, and thus promots the adhesion of Streptococcus mutans and Streptococcus sanguis on the titanium surface.