Effect of oral antimicrobial mouthrinses containing alcohol on viability of Streptococcus mutans and microcosm biofilm and on the prevention of enamel caries lesions.

Purpose: To evaluate the effect of PerioGard, Listerine, Noplak, Malvatricin and Cepacol commercial mouthrinses containing alcohol on the viability of Streptococcus mutans strain and of a microcosm biofilm and on the prevention of enamel demineralization. Methods: The minimum inhibitory concentration (MIC) and minimal bactericidal concentration (MBC) were determined against S. mutans (ATCC 25175). Microcosm biofilm formed from human saliva mixed with McBain saliva was created on bovine enamel for 5 days. From the 2nd to the 5th day, the enamel samples were exposed to McBain with 0.2% sucrose and to the mouthrinses (1 x 60 seconds). The biofilm viability was determined by fluorescence and the enamel demineralization by TMR. Results: The lowest MIC and MBC values were observed for Cepacol, while the highest values were found for Listerine. The mouthrinses significantly increased the number of dead bacteria in biofilm, varying from 38.0+11.2% (Noplak) to 58.5 +/- 13.9% (Listerine), compared to control (12.7 +/- 10.6%), except Periogard (30.1 +/- 12.4%). All mouthrinses reduced mineral loss (P< 0.0001), but only Noplak and Cepacol were able to significantly reduce lesion depth. Cepacol and Noplak presented the best anti-caries effect under this experimental model.