Summary. The aim of this study was to assess the effect of milk with 0, 2.5 or 5 ppm F- on progression and remineralization of caries-like root-surface lesions using a pH cycling model. The root-surface lesions were crea-ted utilizing a partially saturated lactic acid buffer at pH 4.6. Longitudinal sections were cut through the lesion and analyzed using polarized light microscopy (PLM) and microradiography (MRG). The sections were then coa-ted with an acid resistant varnish, except the outer natural surface that would be exposed to water, milk or fluoridated milk for 2 weeks and cycled in a de- and remineralizing systém. The lesions were characterized again by PLM and MRG after treatment. A significant reduction in lesion progression (33.2%) was found by PLM and MRG after treatment with either non-fluoridated or fluoridated milk when compared to the control group. Using quan-titative MRG, minerál change and distribution in the lesions were recorded. A possible protective effect of fluoridated milk on root surface caries was supported by a reduction in the progression of the lesions and an increase in the minerál content within the lesion.

        Key words: fluoridated milk - root caries - pH cycling - demineralization - remineralization