Inhibition of Biofilm Formation and Gene Expression by Silicon Dioxide Nanoparticles and Zinc Oxide/Zeolite Nanocomposites on Streptococcus mutans

BACKGROUND: Streptococcus mutans (S. mutans) is recognized as the primary oral pathogen responsible for dental caries. The formation of biofilms on tooth surfaces is a crucial virulence factor for S. mutans. This study aimed to investigate the antimicrobial and anti-biofilm effects of silicon dioxide nanoparticles (SiO2 NPs) and zinc oxide/zeolite nanocomposites (ZnO/Zeolite NCs) on S. mutans gene expression and biofilm formation. METHODS: Minimum inhibitory concentrations (MICs), minimum bactericidal concentrations (MBCs), sub-MIC, safranin staining, growth curve analysis, and MTT assays were performed to evaluate the anti-biofilm properties of the nanoparticles. The expression levels of the ftf, gtfB, vicR, and gbpB genes were evaluated by real-time PCR. Cytotoxic effects of the nanoparticles were measured by the MTT assay with human gingival fibroblast (HGF2PI2) cells. RESULTS: Both SiO2 NPs and ZnO/Zeolite NCs effectively inhibited S. mutans biofilm formation, with MTT assay results showing a 79% inhibition by SiO2 NPs and 95% by ZnO/Zeolite NCs. Additionally, both nanoparticles reduced the transcription levels of the ftf, gtfB, vicR, and gbpB genes, with no toxic effects observed on HGF2PI2 cells at a concentration of 32 mg/ml. DISCUSSION: These findings suggest that SiO2 NPs and ZnO/Zeolite NCs are promising agents against S. mutans biofilms, with potential applications in oral care products. CONCLUSION: SiO2 NPs and ZnO/Zeolite NCs show significant potential for preventing biofilm formation by S. mutans, representing effective and cost-efficient antibacterial options for oral health.