Methods: Biomass was collected by plaque generation devices which were set on upper molars of twenty consenting volunteers. Plaque biofilms were allowed to develop on enamel surfaces with and without Fuji VII restoration (GIC and Enamel groups respectively). After seven days, the devices were taken out, frozen dry and embedded in resin. Embedded plaque samples were then sectioned using an ultra-microtome. Sections stained with neutral toluidine blue were used the evaluation of biomass volume using an image analyzer. The level of streptococci was measured by TaqMan real-time PCR.
Results: There were no significant differences between the two groups in both biomass density and number of bacteria within dental plaque. The level of bacteria varied widely among subjects. The distribution of streptococci in layers within 400 µm biomass depth from enamel interface showed that the level of streptococci were significant lower in the first layer closed to enamel surface compared with the subsequent layers only in the GIC group (Wilcoxon test, p<0.01) and not in Enamel group.
Conclusion: It can be suggested from this study that the biofilms closed to GIC restorations are not habitats favorable for the growth of oral streptococci.