BACKGROUND: Aim of this in-vitro-study was to assess the remineralization potential of a tooth cleaning tablet with different fluoride content. METHODS: Twenty three caries free impacted third molars were examined, enamel surfaces were wax coated leaving two 3 x 4 mm windows for exposure to demineralization/remineralization cycles. The teeth were randomly assigned to 4 groups of 5 control and 6 experimental teeth. Demineralization by standardised HEC-gel, pH 4.7 at 37 degrees C for 72 h, was alternated by rinsing in remineralization solution, pH 7.0 at 37 degrees C for 72 h, total challenge time 432 h. The negative control group N was treated during remineralization cycles with saline; positive control group P was treated with remineralization solution; experimental group D1 was exposed to remineralization solution containing Denttabs-tablets with 1450 ppm F; experimental group D2 was exposed to remineralization solution and Denttabs-tablets with 4350 ppm F. Each tooth was cut into serial sections and analyzed by polarized light microscopy for assessment of the different zones of white-spot lesions in 3 representative sections. Statistical analysis was based on the Mann-Whitney-Test. RESULTS: Both control groups N(-) and P(+) exhibited characteristic white-spot lesions. The remineralization and the demineralization inhibition of the lesions increased considerably from N<P < D1<D2. Denttabs-2 administration showed partial/total remineralization including lamination and/or disappearance of the body of the lesion. The different results of all 4 groups were statistically highly significant (p < 0.01) with both tests. CONCLUSION: Based on these results the novel Denttabs formulation represents a highly effective oral hygiene product and the remineralization is correlated to the fluoride content.