Objectives: The aim of the present study was to determine the effect of four different desensitizing agents (Gluma Desensitizer, Admira Protect, Hyposen, VivaSens) on root surfaces de- and remineralization in vitro. Methods: The root surfaces of 90 freshly extracted caries-free human molars were thoroughly cleaned, thereby removing the cementum. The teeth were then coated with acid-resistant nail varnish, exposing a rectangular windows. All specimens were demineralized (De) for 14 days with acidified gel (HEC, pH 4.8, 37 degrees C). Before remineralization (Re) using a NaF-containing calcium-phosphate buffer solution one window was covered. Beside an untreated control group, the specimens were distributed among two main groups: In one group the desensitizer was applied before demineralization, in the other subgroup the desensitizer was applied after demineralization. From each tooth, two dentinal slabs were cut. The depth of the demineralized areas was determined using a polarized light microscope. Results: The comparison between de- and remineralized groups showed a significant reduction of lesion depth in all cases (p0.05, Tukeys test). In all cases application of the desensitizers prior to demineralisation resulted in significantly decreased lesion depths compared to the demineralization lesion depths without desensitizer application (p0.05, Tukeys test). Conclusions: It can be concluded that the demineralization of the root surface can be hampered by the application of desensitizing agents in vitro. Furthermore, remineralization might not be negatively affected by the used sealants. Schlagwörter: Dentin, Desensitizer, Demineralisation, Remineralisation, Dentin hypersensitivity