Efeito do ph e da concentração de flúor presente em dentifrícios líquidos no controle de cárie em área não fluoretada: estudo clpinico randomizado.

Abstract

The aim of this randomized clinical trial was to evaluate the effect of pH and fluoride concentration in liquid dentifrices in the control of dental caries in early childhood, in non-fluoridated area. In addition, this study evaluated the influence of pH and fluoride concentration in toenails and in the fluoride uptake in plaque. The sample comprised 212 children aged 2-4 years old and was divided into three groups according to the liquid dentifrices used over 12 months: G1 (n = 39-Active/38-Inactive): 550&#956;gF/g-pH 4.5; G2 (n = 33-Active/35-Inactive): 1100&#956;gF/g-pH 7.0; G3 (n = 33- Active/34- Inactive): 550&#956;gF/g-pH 7.0. Clinical examination was performed at baseline and after 12 months of study, using the diagnostic criteria for caries activity (active, inactive) and surface integrity of the lesion (intact, surface discontinuity, cavity). The lesions that progressed or regressed and the net increment (progression - regression) were recorded for each child. Data were checked for normality and homogeneity using the Kolmogorov-Smirnov and Bartlett tests, respectively. The data failed the normality test, even after logarithmic transformation, and the effect of dentifrice on the progression of lesions in caries-inactive, as well as progression, regression, and net increment of injuries in children caries activity was evaluated by Kruskal-Wallis test. For toenails, the data failed the normality test and were analyzed by Kruskal-Wallis test, after logarithmic transformation, followed by Dunn´s test for individual comparisons. For the plaque, the data were analyzed by ANOVA and Bonferroni test for individual comparisons. In all cases, the level of significance was set at 5%. The acidic and neutral liquid dentifrice with low fluoride concentration showed to be effective for the control of dental caries since the results were similar to those found for conventional one (1100&#956;gF/g). Despite a numerical difference in caries increment after 12 months (G3> G2> G1), no statistical significant difference between groups. Fluoride concentrations in toenails were significantly lower when children used the liquid dentifrice with low concentration of fluoride and low pH (p<0.05).The reduction of pH was able to enhance the incorporation of fluoride in the plaque, and the levels of fluoride in the plaque is not decreased over time. It can be concluded that a low fluoride concentration dentifrice can be effective for controlling dental caries without increasing the risk of dental fluorosis in young children.