Effects of fluoride dentifrices on enamel lesion formation.

An in vitro pH cycling model was used to test the hypothesis that the effects of 3 different fluoride compounds on de/remineralization are a function of the free fluoride ion concentration. Groups of 10 human enamel specimens were treated with one of: (a) amine fluoride (AmF), 1250 ppm F; (b) sodium monofluorophosphate (NaMFP), 1000 ppm F; (c) sodium fluoride (NaF), 1100 ppm F; (d) NaF, 250 ppm F; (e) Placebo (< 1 ppm F) dentifrices; or with aqueous solutions (f) NaF 900 ppm F or (g) NaF 30 ppm F. Lesions were assessed by cross-sectional microhardness. Mean +/- SEM DeltaZ (vol.% x microm) values of 3 dentifrices were: (a) 344 +/- 155, (b) 4259 +/- 257, and (c) 591 +/- 83. The AmF (1250 ppm F) was not statistically significantly different from the NaF (1100 ppm F) dentifrice in this model. The NaMFP (1000 ppm F) dentifrice, without hydrolysis, had only the same efficacy as the NaF (30 ppm F) aqueous solution.