objective: in the present investigation, the anticariogenic effect of fluoride released by two products commonly applied in infants was evaluated. methods: bovine sound enamel blocks were randomly allocated to each one of the treatment groups: control (c), varnish (v) and diamine silver fluoride solution (d). the blocks were submitted to ph cycles in an oven at 37oc. next, surface and cross-sectional microhardness were assessed to calculate the percentage loss of surface microhardness (%sml) and the mineral loss (dz). the fluoride present in enamel was also determined. results: f/px10-3 (anova, p<0.05) in the 1st layer of enamel before ph-cycling were (c, v and d): 1.61a; 21.59b and 3.98c. the %smh (kruskal-wallis, p<0.05) were: -64.0a, -45.2b and -53.1c. %dz values (anova, p<0.05) were: -18.7a, -7.7b and -17.3a. conclusion: the data suggested that the fluoride released by varnish showed greater interaction with sound enamel and provided less mineral loss when compared with silver diamine solution.