The effect of parabens in a mouthwash and incorporated into a sustained release varnish on salivary bacteria

Objectives: The purpose of this study was to evaluate the antimicrobial efficacy of parabens, in a mouthwash and in a slow release device, against cariogenic bacteria in the oral cavity. Methods: Parabens were formulated in a mouthwash or in a topical slow release varnish preparation. In two separate studies, volunteers were asked to use the mouthwash or the slow release varnish applied in a personal night guard device. The levels of mutans streptococci (MS), Lactobacilli (LB) and total cultivated bacteria were measured before and after using the mouthwash or the slow release varnish. Results: The mouthwash containing parabens had a minor and a short-term effect on MS and LB counts in human saliva. The use of slow release varnish containing parabens, applied in a night guard, had a prolonged antibacterial effect on both MS and LB counts. Conclusions: Parabens in a mouthwash had little effect on oral bacteria counts; however, paraben in the slow release device had a significant and an extended effect in reducing oral bacteria. Although substantial reductions in oral bacterial counts were recorded after the use of paraben in a slow release device, this effect could probably be enhanced by an improved pharmaceutical formulation.