The effect of fermented milk on the deciduous enamel in the presence and absence of fluoride: in vitro study

Abstract

Aim. This study assessed the effect of fermented milk on the enamel of primary teeth in the presence and absence of fluoride. Methods. Sixty enamel blocks (4×4 mm) underwent surface microhardness analysis (Knoop). The blocks were randomly distributed into 5 groups of 12 samples in each group according to the following treatments: Group 1) pH cycling and fermented milk (control); Group 2) pH cycling and dentifrice; Group 3) pH cycling and fermented milk and dentifrices; Group 4) varnish and pH cycling and fermented milk; Group 5) varnish and pH cycling and fermented milk and dentifrice. After the treatments, new microhardness determination was carried out and the surface microhardness change ratio was calculated (%SMH). The data were submitted to the Shapiro-Wilk normality test, ANOVA test, Tukey's test and paired t-test (P<0.05). Results. It was observed that after treatment, all groups showed statistically significant reduction (P<0.05) for initial surface microhardness. Group 1 showed the lowest microhardness (73.01+9.68 KNH) compared to groups 2, 3 and 4. Group 5 (172.5±45.85>KNH) showed a greater surface microhardness than Group 4 (122.0±22.33 KNH). Conclusion. It was concluded that the fermented milk adversely altered the microhardness of the samples and that fluorine contributes to a smaller reduction in the microhardness change ratio (SMH%). The combined solution of toothpaste with fluoride varnish provided a lower surface microhardness reduction of the samples.