The dental profession is still pursuing the most effective way to treat white-spot lesions in order to produce a sound and esthetically pleasing enamel surface. The aim of the present research was to evaluate in vitro the effects of a dentifrice with nanohydroxyapatite (nano-HAp) on the roughness, color, lightness, and brightness (gloss) of bovine enamel subjected to pH cycling. Twelve enamel discs prepared from bovine incisors were divided into 2 experimental groups: dentifrice with sodium fluoride (Colgate Total 12 Clean Mint) and dentifrice with nanoHAp (Megasonex). For 14 days, the specimens were subjected to 30 cycles of simulated brushing twice a day as well as to a pH cycling model (6 hours of demineralization and 18 hours of remineralization daily). The roughness, color, lightness, and brightness of all specimens were evaluated at baseline (immediately after specimen preparation) and after 7 and 14 days of treatment. A Tukey test demonstrated that there were no statistically significant differences in the effects of the dentifrices on any parameter after 7 days (P > 0.05). After 14 days, however, there was a statistically significant increase in mean roughness in the group brushed with fluoride dentifrice (P < 0.05). Thus, the nanoHAp containing dentifrice promoted less superficial roughness after 14 days, but both dentifrices were similar in relation to color variation, lightness, and brightness.
Keywords: dental enamel; dentifrice; hydroxyapatite.