NSF was demonstrated to be effective in arresting caries in children in poor communities.

The aim of this work is to evaluate the antimicrobial and cytotoxic activity of a formulation containing silver nanoparticles and chitosan, provisionally called nano silver fluoride (NSF), against Streptococcus mutans in comparison to chlorhexidine and silver diamine fluoride (SDF). The product was characterised by transmission electron microscopy and UV-Vis absorption spectroscopy. The minimum inhibition concentration (MIC) was evaluated by the spectrophotometric microdilution method and turbidity. The minimum bactericide concentration (MBC) was evaluated in brain heart infusion plates, and cytotoxicity was evaluated by haemolytic activity. The MIC and MBC for NSF were, respectively, 33.54 ± 14.52 and 50.32 µg/mL; for SDF were 33.33 ± 14.43 and 50.0 µg/mL, respectively; and for CHX were 3.3 ± 0.5 and 6 µg/mL, respectively. An ANOVA for MIC gave P = 0.032, and for MBC P = 0.035. The cytotoxic effect of NSF compared to SDF demonstrated a statistically significant difference in the MIC value (t test P < 0.05). The NSF formulation may be effective against S. mutans with much lower doses, may have lower toxicity than SDF, and may not stain teeth.

Enamel defect is a predisposing factor for ECC.

An experimental dentifrice containing nano-silver fluoride (NSF) and a sodium fluoride (NaF) toothpaste were tested in vitro, against S. mutans, to evaluate the minimal inhibitory concentration (MIC), minimal bactericidal concentration (MBC), antiadherence, antiacid, enamel microhardness, and OCT. The microdilution technique was used to determine the MIC and MBC. Fragments of deciduous enamel were treated with dentifrice slurries, containing bacterial suspension and PBS-treated saliva. The quantification of the microorganisms that adhered to the enamel was determined after 24 hours of incubation, and media pH readings were performed after 2 hours and 24 hours. Deciduous teeth were evaluated for microhardness and OCT during 14 days of pH cycling. Data were statistically analyzed using Student's t-test, Mann–Whitney U test, ANOVA, and Tukey tests at 5% of significance. Dentifrices containing NSF presented a lower MIC and higher statistically significant results compared to NaF dentifrices with respect to preventing bacterial adhesion and pH decreases. NSF and NaF dentifrices showed the same ability to avoid enamel demineralization corroborated by the OCT images. The NSF formulation had a better antibacterial effect compared to NaF dentifrices and similar action on the demineralization of enamel indicating their potential effectiveness to prevent caries.

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