Abstract Background Nanosilver fluoride (NSF) was developed as an alternative in the prevention of dental caries. Purpose The aim of this study was to test the remineralizing action of NSF on incipient enamel caries and its antimicrobial action on the acid production and adhesion of Streptococcus mutans. Methods Deciduous enamel fragments were treated with sodium fluoride (NaF), NSF and deionized water. Microhardness, fluorescence spectroscopy and optical coherence tomography imaging were performed on each specimen before chemical caries induction, after caries induction and after 14 days of pH cycling. The treated enamel fragments were also placed into test tubes containing bacterial suspension and saliva. The pH readings and quantification of the adhered microorganisms to the dental enamel were determined. Analysis of variance, Kruskal-Wallis, Mann-Whitney, Tukey and mixed linear regression model were applied. Results NSF and NaF were effective in enamel remineralization, with a statistically significant difference (p<0.001) to deionized water, and they had no statistically significant difference between themselves (p>0.005). NSF had greater effectiveness compared to NaF in preventing decreases of pH and adhesion of S. mutans to the enamel surface, with statistically significant (p<0.001) differences. Conclusion NSF may be more effective than conventional fluorides in treating incipient caries lesions due to its remineralization and antibacterial actions.