Effect of nanohydroxyapatite dentifrice on surface roughness of bovine enamel

Abstract

Objective: this study aimed to evaluate in vitro, the effects of dentifrices with hydroxyapatite nanoparticles (nano-HAP) on the roughness of the bovine enamel surface submitted to a pH cycle. Material and Methods: twelve disks of bovine incisors were divided into 2 experimental groups: Group 1, dentifrice with fluoride 1450 ppm—Colgate Total 12 (Colgate-Palmolive Industrial LTDA); Group 2, dentifrice with nano-HAP—Megasonex (Goldspire Group LTDA). The specimens were submitted to 30 cycles of a simulated brushing test, twice a day, and also to a pH cycle model (6 h demineralization at 4.6 pH/18 h remineralization 7.0 pH a day) during 14 days. All specimens were evaluated for their superficial roughness at baseline and after the treatment, using a bench rugosimeter (Surftest SJ 201). Results: the statistical analyses by multiple comparison between pairs, using Holm and Bonferroni test’s demonstrated that after 7 days no statistically significant difference was observed in the behavior of the dentifrices (p > 0.01); however, after 14 days, the roughness increased in group 1 (dentifrice with fluoride) and was statistically significant (p < 0.05). Conclusion: the dentifrice with nano-HAP promoted less superficial roughness after 14 days.