Synergistic Inhibition of Enamel Demineralization by Peptide 8DSS and Fluoride

The biomimetic peptide 8DSS has shown beneficial effects in promoting remineralization of demineralized enamel in vitro. Here we examined the ability of 8DSS alone and in combination with fluoride to inhibit enamel demineralization during pH-cycling mimicking intraoral conditions. Enamel blocks were subjected to 9 days of pH-cycling in the presence of 1,000 ppm NaF (positive control), distilled-deionized water (DDW; negative control), 25 μM 8DSS alone, 25 μM 8DSS with 500 ppm NaF (8DSS-FL) or 25 μM 8DSS with 1,000 ppm NaF (8DSS-FH) twice daily for 1 min each time. The blocks were analyzed in terms of surface microhardness (SMH), fluoride uptake and mineral content. The 8DSS-treated blocks showed significantly lower mineral loss, shallower lesions and higher SMH than the DDW-treated blocks. No significant differences were observed between the blocks treated with 8DSS alone or fluoride alone. The blocks treated with 8DSS alone or DDW showed similar amounts of fluoride uptake, which was the lowest of all the treatment groups. The blocks treated with 8DSS-FL or 8DSS-FH did not differ significantly, and both groups showed significantly greater SMH and fluoride uptake as well as significantly lower mineral loss and shallower lesions than the NaF-treated blocks. Mineral content was significantly higher in the 8DSS-treated blocks than in the DDW-treated blocks from the surface layer (10 µm) to the lesion depth (110 µm), and it was significantly higher in the blocks treated with 8DSS-FL or 8DSS-FH than in the NaF-treated blocks from 10 to 90 µm. These findings illustrate the potential of 8DSS for inhibiting enamel demineralization and for enhancing the anticaries effect of NaF.