ABSTRACT
PURPOSE: To investigate the effects of exogenous dextranase and sodium fluoride on a S. mutans monospecies biofilm. METHODS: S. mutans 25175 was grown in tryptone soya broth medium, and biofilm was formed on glass slides with 1.0% sucrose. Exogenous dextranase and sodium fluoride were added alone or together. The biofilm morphology was analyzed by confocal laser scanning microscopy. The effects of the drug on the adhesion and exopolysaccharide production by the biofilms were evaluated by scintillation counting and the anthrone method, respectively. RESULTS: In this study, we found that the structure of initial biofilm and mature biofilm were partly altered by dextranase and high concentrations of sodium fluoride separately. However, dextranase combined with a low concentration of sodium fluoride could clearly destroy the typical tree-like structure of the biofilm, and led to less bacterial adhesion than when the dextranase or fluoride were used alone (P < 0.05). The amounts of soluble and insoluble exopolysaccharide were significantly reduced by combining dextranase with a low concentration of sodium fluoride, much more than when they were used alone (P < 0.05). These data indicate that dextranase and a low concentration of sodium fluoride may have synergistic effects against S. mutans biofilm and suggest the application of a low concentration of sodium fluoride in anticaries treatment.
Subject(s)
Biofilms/drug effects , Cariostatic Agents/pharmacology , Dextranase/pharmacology , Sodium Fluoride/pharmacology , Streptococcus mutans/drug effects , Bacterial Adhesion/drug effects , Bacteriological Techniques , Drug Combinations , Drug Synergism , Humans , Microscopy, Confocal , Polysaccharides, Bacterial/metabolism , Solubility/drug effects , Streptococcus mutans/physiology , Sucrose/pharmacologyABSTRACT
PURPOSE: To elucidate the amount of exopolysaccharides produced by Streptococcus sobrinus when cultivated at different conditions. METHODS: S. sobrinus was grown in TS broth and was allowed to attach to the cover glass surface to form bioflims. The anthrone method was applied to measure the amounts of soluble and insoluble exopolysaccharides produced by attached S. sobrinus and planktonic ones when cultivated at different time and in different concentrations of sucrose. The data were analyzed using SPSS 10.0 software package, Dunnett's t test was used to compare the difference between the two groups. RESULTS: Attached bacteria synthesized more insoluble polysaccharide than planktonic ones at every sucrose concentration (P<0.05), but almost the same production of soluble polysaccharide (P>0.05). CONCLUSION: The ability of S. sobrinus to synthesize insoluble polysaccharide was enhanced in the adherent phase, which may clarify why bacteria in biofilms are highly cariogenic.
