Aim: This study evaluated the action of an antihistamine-containing syrup (Claritin D) on enamel that was subsequently submitted or not to applications of fluoride dentifrice. METHODS; Two hundred sixty-four slices (n=44 per subgroup) prepared from exfoliated primary molars were evaluated in hardness tests. Six subgroups were submitted to different treatments for 10 days. The controls underwent pH cycling with (positive control) or without (negative control) three daily immersions in fluoride dentifrice/distilled water slurry. The test subgroups related to daytime use of the antihistamine syrup underwent pH cycling and two 5-min applications of Claritin D, coupled or not to the three daily immersions in the fluoride slurry. The subgroups related to nocturnal use of the syrup were submitted to the same procedures of daytime subgroups, respectively, but with one of the applications of Claritin D lasting for 8 h.
Results: The median hardness values obtained after use of the syrup were significantly lower than the initial ones. Equivalent values for subgroups submitted to fluoride applications in addition to treatment with the syrup were significantly higher.
Conclusion: It was concluded that the antihistamine-containing syrup reduced the hardness of primary enamel and that, in this experiment, the use of fluoride dentifrice was able to diminish this erosive effect.