Antimicrobial and optical properties of a new biogenic silica-coated silver nanoparticles incorporated into experimental resin

Evaluate the effects of incorporating silica-coated silver nanoparticles (Ag@SiO2 NPs) into odontological clinic resin materials. Silver nanoparticles coated with silicon dioxide were added to the experimental resin matrix at 1, 3, and 5wt%. Degree of conversion (DC), optical properties (total transmittance and color change), and microstructural analysis were evaluated. Materials were tested for silver ion release, cytotoxicity in dental pulp fibroblasts, Streptococcus mutans biofilm growth by Colony-Forming Unit (CFU) and confocal laser scanning microscopy (CLSM). Groups had a similar DC, despite significant differences observed in transmittance and color change analysis for all groups with NPs. Silver ion release values were below the detection limit after 72h for all groups, and NPs incorporation did not show a statistical difference from the control on pulp fibroblasts assay. After 72h, the CFU count was significantly reduced by 74% from 3wt% of Ag@SiO2NPs. CLSM evaluation on colonies showed a dose-dependent decrease in the emitted fluorescence. The application of Ag@SiO2 NPs in a resinous matrix, demonstrates a significant reduction of CFU in oral biofilm, at concentrations from 3wt%, without an increase in cytotoxicity. The reduced transmittance values did not affect the DC, although a significant color change was perceived in all concentrations. Nanoparticles, Silver Compounds, Composite Dental Resin, Anti-Bacterial Agent, Optical Imaging.