Co-operative effect of exogenous dextranase and sodium fluoride on multispecies biofilms

Background/purpose: The co-operative effect of exogenous dextranase (Dex) and sodium fluoride (NaF) on Streptococcus mutans monospecies biofilms is impressive. Here we investigated the effects of the combination on a mature cariogenic multispecies biofilm and analyzed the potential mechanism. Materials and methods: A multispecies biofilm of S. mutans, Lactobacillus acidophilus, and Actinomyces viscosus was established in vitro. Dex and NaF were added separately or together. The effects of the agents on the biomass were measured. The exopolysaccharide production was determined with the scintillation counting method. The viability and morphology were evaluated using colony forming unit and confocal laser scanning microscopy, respectively. Results: In general, biofilms treated with Dex and a little concentration of NaF exhibited a lower biomass, exopolysaccharide production, and viability compared with the control group (P