Anti-adhesion and anti-biofilm activity of slightly acidic electrolyzed water combined with sodium benzoate against Streptococcus mutans: A novel ecofriendly oral sanitizer to prevent cariogenesis

Streptococcus mutans (S. mutans) can promote the establishment of high acidic biofilms and therefore have contribution to the development of dental caries. Alleviating the acidic environment and/or disrupting the structure of S. mutans biofilm are effective approaches against dental caries, rather than killing the microorganisms. The anti-biofilm effect of slightly acidic electrolyzed water (SAEW) is entirely based on the hypochlorous acid and ROS generation. In this study, sodium benzoate (NaB) acts as a pH adjuster and enhances SAEW's anti-biofilm activity. The results showed that the SAEW combined with NaB (SAEW + NaB) is highly effective in controlling biofilm. The adhesive strength of biofilm was significantly reduced by SAEW, and NaB was found to have a synergy effect with SAEW. Biofilm treated by SAEW + NaB was entirely removed by 60 s of ultrasonic wave, whereas the untreated biofilm can only be removed to a lesser extent. Atomic force microscope (AFM) analysis revealed that SAEW and NaB reduced the height of S. mutans biofilm. The metabolites derived from biofilm positively changed during the periodic 1-min treat, the production of lactic acid was hindered by the treatment. Altogether, these findings suggested a novel therapeutic intervention against S. mutans biofilm by targeting the cariogenic action.