Resin-tooth adhesive interfaces after long-term function

Purpose: To characterize with scanning electron microscopy (SEM), the morph ology of adhesive interfaces that had been functioning in an oral cavity fo r several years, Materials and Methods: Cavities were prepared in vivo in c aries-affected primary molars under local anesthesia. After removal of the entire carious lesion, the cavity was restored with a dentin adhesive syste m (Scotchbond Multi-Purpose). After several yrs, as the successor permanent teeth erupted, the resin-filled teeth were extracted. Then, the extracted resin-restored primary molars were cross-sectioned perpendicular to the adh esive interface using a low speed diamond saw and then polished for SEM exa mination. Results: Morphological changes, such as digestion of the collagen fibrils and deterioration of the bonding resin and hybrid layer, were obse rved at the interface of the oral environment specimens. The results of thi s study demonstrated that degradation of resin-dentin bond structures appea red to occur in the human oral environment over time.