OBJECTIVEThis research aimed to study the inhibitory effect of xylitol on the growth and acid production of Actinomyces viscosus (A. viscosus).

METHODSWe cultivated A. viscosus in anaerobic conditions with different concentrations (128, 64, 32, 16, 8, and 4 g x L(-1)) of xylitol brain heart infusion liquid medium and determined the minimum inhibitory concentration (MIC). Subsequently, we measured the pH value of the control group, as well as those of 1/2, 1/4, 1/8 MIC, and MIC concentration groups at 1.5, 3, 6, 12, 24, and 48 h. The Delta pH and OD550 at 2, 4, 6, 8, 10, and 12 h were calculated. We discovered that the minimum xylitol concentrations suppressed 50% and 90% A. viscosus biofilm formation (i.e., MBIC50 and MBIC90). SPSS 19.0 was used to analyze the collected data, and conclusions were drawn afterward.

RESULTSXylitol inhibited the growth ofA. viscosus at MIC of 64 g x L(-1). After 12 h, the differences of pH value among groups were all statistically significant (P < 0.05), and Delta pH increased when the MIC concentration decreased. Except for the 1/2 MIC and MIC groups, the differences of OD550 among groups had no statistical significance (P>0.05), and OD550 also increased when the MIC concentration decreased. These results imply that the ability ofA. viscosus to grow and produce acid in 1/2 MIC and MIC conditions will be reduced with the increase in xylitol concentration. The value of MIBC50 was 64 g x L(-1), whereas the value of MIBC90 was 128 g x L(-1). This finding indicates that the xylitol medium can restrict A. viscosus biofilm formation.

CONCLUSIONXylitolcan effectively inhibit the growth, adhesion, and acid production ofA. viscosus, protecting teeth from cariogenic bacteria and preventing caries to a certain extent.