No abstract

We used a polymicrobial (PM) biofilm model to examine associations of bacterial adhesiveness with surface characteristics of various dental materials. Four types of dental materials (apatite pellet, zirconia, ceramic, and composite resin) with rough and mirror surfaces were used. Surface roughness, surface free energy, zeta potential, and colony-forming units (CFUs) of the biofilm formations were measured. Biofilms were cultured for 24 h under anaerobic conditions, plated onto blood agar medium, and anaerobically cultured for 4 days. After culturing, CFU per mm 2 was calculated, and samples were observed under a scanning electron microscope. Means and standard deviations of the experimental data were estimated, and one-way ANOVA and Tukey multiple comparison assays were performed. Pearson correlation coefficients were obtained for the CFU and surface characteristics. Surface roughness and surface free energy appeared to affect generation of PM biofilms on oral materials, and zeta potential was involved in generation of PM biofilms on mirrorground oral materials.

This study investigated the in vitro anti-demineralization effects of resin-based temporary filling materials containing surface prereacted glass-ionomer (S-PRG) filler on dentin. Bovine root dentin specimens with a 3×3 mm experimental surface were divided into four treatment groups: DuraSeal (DU) as a control, S-PRG filler-free temporary material (S0), material containing 10% (S10) and 20% (S20) S-PRG filler. Each material was applied to 3×2 mm of the experimental surface, and the specimens were immersed in 8% methylcellulose gel demineralization system for one week at 37˚C. Mineral profiles and integrated mineral loss (IML) of lesions induced on the surface (3×1 mm) adjacent to the materials were computed by transversal microradiography. S10 and S20 yielded thick surface layers and shallow lesion bodies, with significantly lower IML than DU and S0 (p<0.05, Tukey's test). These findings indicate that temporary filling resin-based materials containing over 10% of S-PRG filler content have anti-demineralization effects on adjacent dentin.

Three novel aqueous fluoride surfactants (F4, F6, and F8) and a positive control (10F2S-3I) were applied to bovine enamel and the surface free energy was calculated by measuring the surface contact angles of three liquids: distilled water, α-bromonaphthalene and diiodomethane. The specimens were stored in water for 90 days, and then immersed in acetic acid/sodium acetate. The modified specimens recorded higher contact angles and lower surface free energy immediately after treatment than the control (p<0.05). Less calcium dissolved from the modified enamel surfaces than the control, with the F8-modified specimen registering significantly lower values than those of the F4, F6 and 10F2S-3I groups (p<0.05). These results suggest that the novel aqueous phosphate-type fluoride surfactant F8 is the most effective anti-cariogenic surface modifier.

No abstract