Inhibition of streptococcal biofilm by hydrogen water.

OBJECTIVES: The accumulation of oral bacterial biofilm is the main etiological factor of oral diseases. Recently, electrolyzed hydrogen-rich water (H-water) has been shown to act as an effective antioxidant by reducing oxidative stress. In addition to this general health benefit, H-water has antibacterial activity for disease-associated oral bacteria. However, little is known about the effect of H-water on oral bacterial biofilm. The objective of this study was to confirm the effect of H-water on streptococcal biofilm formation.

METHODS: In vitro streptococcal biofilm was quantified using crystal violet staining after culture on a polystyrene plate. The effect of H-water on the expression of genes involved in insoluble glucan synthesis and glucan binding, which are critical steps for oral biofilm formation, was evaluated in MS. In addition, we compared the number of salivary streptococci after oral rinse with H-water and that with control tap water. Salivary streptococci were quantified by counting viable colonies on Mitis Salivarius agar-bacitracin.

RESULTS: Our data showed that H-water caused a significant decrease in in vitro streptococcal biofilm formation. The expression level of the mRNA of glucosyltransferases (gtfB, gtfc, and gtfI) and glucan-binding proteins (gbpC, dblB) were decreased remarkably in MS after H-water exposure for 60s. Furthermore, oral rinse with H-water for 1 week led to significantly fewer salivary streptococci than did that with control tap water.

CONCLUSIONS: Our data suggest that oral rinse with H-water would be helpful in treating dental biofilm-dependent diseases with ease and efficiency.