Effect of bicarbonate on fluoride reactivity with enamel

• Main Author: Peres, Paulo Edelvar
• Publication Date: 2008
• Other Authors: Santos, Denis C. L., Tabchoury, Cínthia Pereira Machado, Cury, Jaime Aparecido
• Format: Article
• Language: eng
• Source: Revista odonto ciência (Online)
• Download full: https://revistaseletronicas.pucrs.br/ojs/index.php/fo/article/view/4285
• topic: Dentifrice; fluoride; baking soda; enamel; reactivity; Cariology

Purpose: Bicarbonate (HCO-3 ) is an alkaline and buffering substance found in dentifrices, which could improve the anti-caries effect of fluoride (F). However, HCO-3 could reduce the formation of calcium fluoride-like (CaF2), the most important product of F reactivity with enamel, whose formation is higher in low pH. The aim of this in vitro study was to evaluate if HCO-3 interferes with the reactivity of F with human enamel. Methods: Five dentifrice formulations were evaluated: placebo of F and HCO-3 (pH 7.0); HCO-3 (pH 9.0); F (pH 7.0); F (pH 9.0) and F+HCO-3 (pH 9.0). F dentifrices contained NaF and all dentifrices were silica-based. The concentrations of total F (TF), CaF2 and firmly bound F (FA, fluorapatite-like) formed in enamel after 1-min reaction with dentifrice slurries (1:3) were determined. Results: The formation of TF, CaF2 and FA was reduced in 22.1 %, 47.9 % and 4.8 %, respectively, by the presence of HCO-3 in the dentifrice formulation. Conclusion: This in vitro data suggest that addition of HCO-3 to a dentifrice may interfere with the reactivity of F with enamel, reducing mainly the concentration of CaF2 formed. Key words: Dentifrice; fluoride; baking soda; enamel; reactivity