Effect of adding soluble calcium and pyrophosphate to fluoride toothpaste on enamel remineralization: An in vitro study.

Objectives: To compare the remineralization ability of a fluoride, soluble calcium, and pyrophosphate (FCaP) toothpaste with that of a fluoride-only toothpaste.

Design: Three toothpastes with identical base compositions were prepared: 1450 ppm fluoride (F = 76 µmol/g), 1450 ppm FCaP (F = 76 µmol/g, Ca = 23 µmol/g, P = 23 µmol/g), and 5000 ppm fluoride (F = 263 µmol/g). Soluble fluoride and calcium levels were evaluated by diluting each toothpaste with water (100 mg/10 mL). Bovine enamel specimens with artificially induced subsurface lesions underwent a 21-day pH cycling regimen, with continuous remineralization involving daily 2-hour demineralization and 3-minute toothpaste treatment. Post-pH cycling, quantitative light-induced fluorescence measurement, microhardness testing, and elemental composition analysis were performed (n = 10).

Results: The 1450 ppm FCaP toothpaste retained over 95 % soluble fluoride and 30 % soluble calcium. pH cycling test results revealed significantly higher remineralization and fluoride penetration in the 1450 ppm FCaP group than those in the 1450 ppm fluoride-only group (p < 0.05, Steel-Dwass multiple comparison test). No significant differences in enamel calcium-to-phosphorus ratios were observed among the three toothpastes. Interestingly, the 5000 ppm fluoride-only group showed significantly higher fluoride penetration but no improvement in remineralization than that in the other two groups.

Conclusions: The 1450 ppm FCaP toothpaste enhanced enamel remineralization more effectively than the fluoride-only toothpaste did. Clinically, FCaP toothpaste can help control dental caries, especially in individuals with low salivary calcium levels.