Bonding of Fissure Sealant to Etched Demineralized Enamel (Lesions)

Abstract

Different aspects of the acid-etching of enamel lesions and subsequent bonding of resins were studied, in particular the measurement of the mineral loss as a result of etching and the structure of (etched) lesions in comparison with sound enamel in relation to bonding of resins. The experiments were performed on artificial lesions produced in an acidified gelatine-gel system. During the etching of enamel lesions less calcium was removed as compared to corresponding sound controls. Nevertheless the thickness of the etch steps for the two types of specimens was about the same. This relatively high resistance of the lesions to acid etching is attributed to the high fluoride content of the lesions. The hardness of the lesions and the sound enamel controls was measured at 15 μm below the surface. These values in both cases showed a decrease with successive etchings. The scanning electron microscopic appearance of the lesions revealed that after 1-min acid etching the surface topography was similar to sound enamel, with a prism pattern apparently suitable for resin tag formation and adhesion. The sealing quality of a lesion by a resin, and the integrity of the resultant bond, was tested by subjecting the specimens to a regimen of thermocy cling between 4 and 75 °C. In all cases the etched lesion turned out to support a successful bond. The study demonstrates that enamel lesions are an acceptable and suitable substrate for resin adhesion provided the enamel surface has been acid-etched.