Influence of two dentin bonding systems on the demineralization of the root surface

It has been assumed that dentin adhesives can prevent root surface caries. The aim of this study was to determine the caries-protective effect of two different dentin bonding systems on the demineralization of root surfaces i n vitro. The root surfaces of 60 freshly extracted caries-free human molars were thoroughly cleaned and polished, thereby removing the cementum. The t eeth were then coated with acid-resistant nail varnish, exposing two rectan gular windows of 6 mm(2) each. One window served as an untreated control, w hile the other window was treated with a dentin bonding system. The specime ns were distributed among the following experimental groups-Group 1: Syntac , Heliobond (no air thinning); Group 2: Syntac, Heliobond (as recommended); Group 3: Syntac, without Heliobond; Group 4: Prime & Bond 2.0 (no air dryi ng); Group 5: Prime & Bond 2.0 (as recommended); Group 6: Prime & Bond 2.0 (dentin pretreated with 36% phosphoric acid). Subsequently, all specimens w ere demineralized for 6 days with acidified gel (HEC, pH 4.8, 37 degrees C) . From each tooth, three dentinal slabs were cut perpendicular to the polis hed surface of the windows. The slabs were ground to a thickness of 80 mu m and imbibed with water. The depth of the respective demineralized areas wa s determined using a polarized light microscope. All control specimens exhi bited lesions with a mean depth of 67 mu m. In Groups 2, 3, and 5 the lesio n depth was reduced significantly, while in Groups 1,4, and 6 no lesions co uld be detected. It was concluded that the demineralization of the root sur face can be impeded by application of the dentin adhesives tested.