Anti-caries effect of fluoridated milk-based drink consumed by older adults on an in vitro root caries experimental model

Objective: This study aimed to evaluate the anti-caries effect of a fluoridated milk-based drink on a root caries model by assessing mineral loss and both biofilm microbial viability and acidogenicity under increasing concentrations of fluoride supplementation. Design: Streptococcus mutans UA159 biofilms were grown on root dentin slabs for five days. The slabs were randomly assigned to following groups: milk-based drink (G1) and milk-based drink supplemented with 5-ppm NaF (G2), 10 ppm NaF (G3), and 20 ppm NaF (G4). A 10% sucrose and 0.9% NaCl solution were used as positive and negative-caries controls, respectively. Slabs/biofilms were exposed to the different treatments 3 times/day for 5 min. To estimate biofilm acidogenicity, the pH of the spent media was serially measured to calculate the area above the curve. Viable bacteria and dentin demineralization were assessed after the experimental phase. Results were compared using ANOVA followed by the Tukey test. Results: G1 exhibited slightly lower acidogenicity than the positive caries control group (p <0.05). G2, G3, and G4 induced lower acidogenicity than 10% sucrose and the non-supplemented milk-based drink. The lowest acidogenicity was found in G4 (p < 0.05). Fluoride-supplemented milk-based drinks (G2, G3, and G4) resulted in lower bacterial counts (p < 0.05) and induced lower demineralization (p < 0.05) than the positive caries control and non-supplemented milk-beverage (G1). There was a dose-dependent inhibition of demineralization with fluoride-supplemented milk-based drinks. Conclusions: Fluoride supplementation of a milk-based drink for older adults may reduce its cariogenicity in mot dentin.