Cytotoxicity of novel fluoride solutions and their influence on mineral loss from enamel exposed to a Streptococcus mutans biofilm

•The new fluoridated nanocomplexes presented a non-cytotoxic behaviour.•Hydroxypropyl-β-cyclodextrin/γ-cyclodextrin with TiF4 decreased enamel loss.•All solutions showed inhibitory properties against S. mutans. This study evaluated the cytotoxicity, antimicrobial activity and in vitro influence of new fluoridated nanocomplexes on dental demineralization. The nanocomplexes hydroxypropyl-β-cyclodextrin with 1% titanium tetrafluoride (TiF4) and γ-cyclodextrin with TiF4 were compared to a positive control (TiF4), a blank control (without treatment) and negative controls (hydroxypropyl-β-cyclodextrin, γ-cyclodextrin, deionized water), following 12- and 72-hour complexation periods. The cytotoxicity was assessed using the neutral red dye uptake assay at T1–15 min, T2–30 min and T3–24 h. A minimum bactericidal concentration (MBC) against Streptococcus mutans (ATCC 25175) was performed. Enamel blocks were exposed to an S. mutans biofilm, and the percentage of surface microhardness loss was obtained. Biocompatibility and microhardness data were analysed using ANOVA/Tukey tests (p