Evaluation of fluoride release from experimental TiF(4) and NaF varnishes in vitro

Fluoride varnishes play an important role in the prevention of dental caries, promoting the inhibition of demineralization and the increase of remineralization. OBJECTIVE: This study aimed to analyze the amount of fluoride released into water and artificial saliva from experimental TiF(4 )and NaF varnishes, with different concentrations, for 12 h. MATERIAL AND METHODS: Fluoride varnishes were applied on acrylic blocks and then immersed in 10 ml of deionized water and artificial saliva in polystyrene bottles. The acrylic blocks were divided in seven groups (n=10): 1.55% TiF(4 )varnish (0.95% F, pH 1.0); 3.10% TiF(4 )varnish (1.90% F, pH 1.0); 3.10% and 4% TiF(4 )varnish (2.45% F, pH 1.0); 2.10% NaF varnish (0.95% F, pH 5.0); 4.20% NaF varnish (1.90% F, pH 5.0); 5.42% NaF varnish (2.45% F, pH 5.0) and control (no treatment, n=5). The fluoride release was analyzed after 1/2, 1, 3, 6, 9 and 12 h of exposure. The analysis was performed using an ion-specific electrode coupled to a potentiometer. Two-way ANOVA and Bonferroni's test were applied for the statistical analysis (p<0.05). RESULTS: TiF(4 )varnishes released larger amounts of fluoride than NaF varnishes during the first 1/2 h, regardless of their concentration; 4% TiF(4) varnish released more fluoride than NaF varnishes for the first 6 h. The peak of fluoride release occurred at 3 h. There was a better dose-response relationship among the varnishes exposed to water than to artificial saliva. CONCLUSIONS: The 3.10% and 4% TiF(4 )-based varnishes have greater ability to release fluoride into water and artificial saliva compared to NaF varnish; however, more studies must be conducted to elucidate the mechanism of action of TiF(4 )varnish on tooth surface.