A novel formulation effective in killing oral biofilm bacteria.

To determine if a novel formulation is effective in killing oral biofilm streptococci in vitro and in vivo. Efficacy of 0.5% levulinic acid and 0.05% sodium dodecyl sulfate (SDS) in killing Streptococcus gordonii CH1, Streptococcus gordonii DL1, Streptococcus mitis NCTC10712, Streptococcus oralis KS32AR, Streptococcus mutans BM71, and Streptococcus mutans GS5 in their biofilm form was measured in vitro, using microtiter plates and subsequent counts on Mitis-Salivarius agar plates. The safety and efficacy in vivo were evaluated using a mouse model. Our anti-microbial formulation completely eliminated all the biofilm streptococcal species tested within 30 seconds (a reduction of 10(7) CFU/ml), whereas the positive control Listerine only demonstrated moderate reduction in vitro. Application of the formulation twice a day for 7 days in the murine oral cavity resulted in significantly more reduction of established S. gordonii DL1 oral biofilm bacteria than Listerine. The formulation did not cause any adverse effect in the murine oral cavity within a 2-week period. We have demonstrated that the novel mouth rinse exhibits high efficacy in killing oral bacteria in their biofilm forms, results in no adverse effect in vivo, and contains alcohol-free components.