Fluoride release and remineralizing potential of varnishes in early caries lesions in primary teeth

Abstract

This study evaluated the fluoride (F) release and remineralizing potential of varnishes containing sodium fluoride (5% NaF), 5% NaF with CPP-ACP and 5% NaF with TCP in early caries lesions in primary teeth. To determine the F release at 1, 4, 6, 24, 72, and 168 hr, strips were covered with the varnishes and immersed in purified water (n = 7). The varnishes and purified water (negative control) were applied on enamel blocks with early caries lesions (n = 16). Enamel blocks were stored in artificial saliva and submitted to a pH-cycling. The area of enamel hardness loss (Delta S) was analyzed by microhardness, lesion depth by polarized light microscopy (PLM) and the chemical analysis by Energy-dispersive X-ray spectroscopy. Data were submitted to Shapiro-Wilk, two-way and one-way ANOVA, Tukey and paired t-tests (alpha = 5%). All varnishes released F, but 5% NaF with CPP-ACP had the highest release at 4, 6, 24, and 72 hr (p < .05) followed by 5% NaF with TCP and 5% NaF. No significant difference in Delta S was observed among varnishes (5% NaF = 4,098.4 +/- 1,407.9; 5% NaF with CPP-ACP = 4,164.0 +/- 1,019.3; 5% NaF with TCP = 4,183.2 +/- 1,527.2; p = .999), but all of them differed from the negative control group (6,757.8 +/- 2,274.7; p < .001). Lesion depth was lower in varnishes groups compared to negative control (% reduction: 5% NaF = 41.8%, 5% NaF with CPP-ACP = 38.8%, and 5% NaF with TCP = 36.3%; p < .001). Similar Ca, P, and Ca/P ratio percentages among groups and F was not detected after the treatments. All fluoride varnishes showed potential to enhance remineralization of early caries lesions in primary teeth.