Antimicrobial Activity of Xylitol Containing Dentifrice on Mutans Streptococci

In several human trials, xylitol products have been shown to significantly reduce the incidence of caries. While the mutans streptococci are known to be the main agent of dental caries by triggering dental plaque and acid formation, varying approaches have been applied to control dental caries in the community level. A recent study has showed that the amount of Colony Forming Units (CFU) of salivary mutans streptococci after tooth brushing with dentifrice containing xylitol is lower than when using non-xylitol dentifrice. Objective: The aim of the study was to determine the sensitivity of mutans streptococci on dentifrice containing xylitol. Methods: Inhibition of bacterial growth by dentifrice containing xylitol was examined in vitro by determining the inhibition zone (agar diffusion method), minimum inhibition concentration (MIC) and minimum bactericidal concentration (MBC). The micro-organisms tested were Streptococcus mutans strains Ing-Britt, KPSK2, LM7 and JC2, and S. sobrinus strain B13. Results: Xylitol in dentifrice resulted in an inhibition zone of 1.50 to 2.10 mm for the tested strains of S. mutans, and 2.20 mm for the tested strain of S. sobrinus. The resulting MIC was 10^-3 g/ml and MBC 10^-1 g/ml for all tested strains of S. mutans and S. sobrinus. Conclusion: It is concluded that dentifrice containing xylitol has antimicrobial activity against S. mutans strains Ing-Britt, KPSK2, LM7 and JC2, and S. sobrinus strain B13. The results suggest potential for caries risk mitigation in the future.