Effect of acidic fluoride treatments on early enamel erosion lesions--a comparison of calcium and profilometric analyses.

The protective effect of fluoride solutions against acidic challenge on enamel was tested in vitro using calcium- and profilometer analyses. HF-, SnF(2)-, TiF(4)- and NaF solutions (0.1M F(-), with a pH of 2.0, 2.9, 1.5, 7.3, respectively) and H(2)O were tested on a total of 60 enamel specimens divided into 10 groups. Prior to and after F-treatment five groups were exposed for 1 min to 0.01 M citric acid, and the other five groups for 10 min to 0.1M citric acid. Enamel specimens were measured by profilometry at baseline and before and after each acidic challenge. [Ca] in the collected citric acid samples was measured by atom absorption spectroscopy (AAS). DeltaCa and Delta surface height were calculated for each specimen and the data were analysed using one-way ANOVA, Tukeys test and Pearson r correlation. AAS showed that the acidic F-treatments significantly reduced enamel dissolution for both the 1 min and 10 min acidic challenge. Profilometry showed no significant differences between the F-solutions for the 1 min groups. Significant differences could be seen between the fluorides for the 10 min groups and there was a large correlation between the profilometric and AAS results. In conclusion, all fluoride solutions reduced enamel dissolution when specimens were exposed to citric acid. The profilometer was not sensitive enough to measure the effects of the different fluorides against a low acidic challenge. AAS was able to show these differences and for the 10 min acidic challenge there was a good correlation between the results from the two methods.