The combined enamel remineralization potential of arginine and fluoride toothpaste.

OBJECTIVE(S): This study examined the remineralization potential of arginine (Arg) in NaF toothpaste. METHODS: Fifty enamel specimens allocated to five groups (n = 10) were subjected to artificial caries formation. A 10-day pH-cycling was performed to treat specimens as per group - [1]: 2% Arg - NaF, [2]: 4% Arg - NaF, [3]: 8% Arg - NaF, [4]: NaF and [5]: deionized water. The test solutions were subjected to pH measurement, fluoride estimation, Na-Cl element analysis using ICP-EOS and FTIR analyses. Mineral density of the specimens were assessed using micro-CT; while Ca/P ratio and surface fluorine concentration were determined using energy dispersive x-ray spectroscopy (EDS) and enamel fluoride uptake (EFU) by acid-etch method. RESULTS: pH, fluoride concentration and Na-Cl ratio exhibited significant difference amongst groups (p < 0.001). FTIR analysis showed presence of free amino acids in 2% and 4% Arg-NaF group. The mean mineral gain (0.40 +/- 0.07 g/cm(3)) and percent remineralization (27.91 +/- 4.66%) of 2% Arg-NaF group were significantly higher than the other 4 groups (p < 0.001). Conversely, the median Ca/P ratio for 2% Arg-NaF (1.60) was significantly higher than deionized water (1.53) (p = 0.029). The mean surface fluorine concentration of specimens treated with 2% Arg-NaF (1.51 +/- 0.14%) was significantly higher than treatment with NaF (1.02 +/- 0.28%) (p < 0.001). The EFU of 2% Arg-NaF group (6.84 +/- 1.59 mug/cm(2)) was significantly higher than NaF group (5.22 +/- 1.88 mug/cm(2)) (p < 0.001). CONCLUSION: Incorporation of 2% arginine in NaF toothpaste significantly increased the remineralization of enamel caries-like lesion when compared to NaF toothpaste; while 4% and 8% arginine in NaF toothpastes were ineffective in improving enamel remineralization. CLINICAL SIGNIFICANCE: In high-risk patients, daily use of 2% arginine in NaF toothpaste might provide a synergistic anti-caries effect given the proven prebiotic benefits of arginine in caries prevention and the demonstrated remineralization effect in the present study.