Effect of a low-fluoride-content, two-component rinse on fluoride uptake and on de--and remineralization of enamel lesions: an in vitro study.

The effect of calcium (Ca) concentrations and added ethanol on fluoride (F) depositions by experimental two-component rinses, each consisting of a Ca-containing and an F-containing component, was evaluated in an in vitro system. Among the tested rinses, a 3 mmol/l F two-component rinse with 200 mmol/l Ca and 10% v/v ethanol was found to produce the greatest F deposition relative to the F concentration in the rinse. Specifically, this rinse produced an F deposition that was about 7 times greater than a conventional 13.2-mmol/l sodium fluoride (NaF) rinse. In a second experiment, an in vitro pH cycling model was used to evaluate the potential anti-caries effects of 4 rinses: (1) placebo rinse (no F), (2) 13.2-mmol/l NaF rinse, (3) 52.6-mmol/l NaF rinse, and (4) the 3-mmol/l F two-component rinse in a 7-day in vitro pH cycling model. The changes in lesion mineral contents, delta(DeltaZ), as assessed by quantitative microradiographic measurements, were as follows [mean +/- standard deviation, n = 10]: (1) 72.5+/-10.2 microm, (2) 43.4+/-5.6 microm, (3) 17.3+/-10.2 microm and (4) 45.3+/-5.2 microm. These results showed that the 3-mmol/l F two-component rinse produced the same (p>0.05) protection against demineralization as did the 13.2-mmol/l NaF rinse which had 4 times the fluoride content. The results suggest that it is possible to formulate an effective low-F two-component rinse.