Effect of Antimicrobial Mouthrinses on Enamel Caries Under Microcosm Biofilm

Objectives: This study aimed to compare the antimicrobial (anti-biofilm) and anti-caries (enamel demineralization prevention) effects of commercial mouthrinses (alcohol and alcohol free) on enamel under microcosm biofilm.
Methods: The commercial mouthrinses (alcohol and alcohol free) tested were: PerioGard^®, Listerine^®, Noplak^®, Malvatricin^® and Cepacol^®. PBS was used as a control. Microcosm biofilm was produced on bovine enamel from a mixture of human saliva and McBain saliva at the first 8 h. From this first moment until the end of the experiment, the enamel samples were exposed to McBain saliva containing 0.2% sucrose and, once a day, they were treated with the mouthrinses for 1 min. The biofilm viability was determined by fluorescence using confocal microscopy and the enamel demineralization was quantified using TMR. The data was compared using two-way RM ANOVA followed by Bonferroni’s test (p<0.05).
Results: With respect to antimicrobial effect, mouthrinses alcohol free showed higher reduction of biofilm viability than those with alcohol, regardless of the type of mouthrinse. When the mouthrinses were compared, the best antimicrobial effect was found for Listerine^® (especially with alcohol), Malvatricin^® (especially alcohol free) and Cepacol^® (p<0.0001). With respect to anti-caries effect, no influence of alcohol was found, with exception of Listerine^® and Cepacol^®. When the mouthrinses were compared, no difference was seen among them in the presence of alcohol. However, when the alcohol-free mouthrinses were compared, the best anti-caries effect was found for Periogard^®, Noplak^® and Malvatricin^® (p<0.0001).
Conclusions: The antimicrobial effect is influenced by the presence or not of alcohol and the type of mouthrinse, which does not reflect on the anti-caries potential of the tested mouthrinses under this experimental model.