Comparison of the effects of 0.1% F- and 0.025% F- on mineral loss in enamel under intra oral cariogenicity test conditions.

Although the caries reducing effect of fluoride (F-) is very well known, the optimal fluoride concentration is still unknown. Therefore we compared the effects of a high (0.1% F-) with a low (0.025% F-) concentration under Intra Oral Cariogenicity Test (ICT) conditions using microhardness measurement and microdissection techniques with which it is possible to quantify the amount of Ca and P present in consecutive enamel layers. No significant differences could be demonstrated between high and low fluoride concentrations in the mineral loss in the surface layer as well as in penetration depth measured perpendicularly to the surface. The reduction of mineral loss after ICT was more pronounced with high fluoride concentrations especially in layers deeper than 150 microns. Using 0.025% F- this effect was restricted more towards the surface. Concomitantly with both F- concentrations a higher Ca/P ratio was observed compared to the sucrose treated or untreated controls.