Enhanced fluoride uptake from mouthrinses

It has been shown in laboratory and animal studies that tooth enamel becomes considerably more reactive toward low levels of fluoride after receiving pre-treatment which forms dicalcium phosphate dihydrate (DCPD) in the enamel as an intermediate. This in vitro study was undertaken to determine the effect on human enamel fluoride uptake of incorporating DCPD-forming rinses into a conventional fluoride rinsing program. In one group, enamel samples received a one-minute rinse with 0.2% NaF each day for 20 days. Samples in the second group were treated identically, except that they were also given a one-minute DCPD-forming rinse prior to the first, sixth, eleventh, and sixteenth fluoride rinses. At the end of the rinsing program, all samples were washed in 1 M KOH to remove labile fluorides. The enamel biopsy data showed that the fluoride uptake resulting from 0.2% NaF alone was not statistically significant, whereas uptake produced by the DCPD-forming plus NaF rinses was significant. The results suggest that the DCPD-forming rinse may improve the efficacy of fluoride rinse programs.