Comparison of dentine-resin interface in total-etch and self-etching adhesives using electron microscopy

The important condition for the adhesive bond between dentine and composite filling is the change of dentine property from hydrophilic to hydrophobic. Substances able to accomplish this change, dentinal adhesives, have undergone complex development. Recently, the so-called self-etching adhesives have been formulated. The aim of the present paper was to compare the structural pattern of dentin/resin interface after the application of dentinal adhesives used in total- and self-etching technique. Dentinal adhesives Single bond, Prime bond, Prompt-L-pop Adper, and Xeno III were used. The former two belong to the total etch technique, the latter two to the self-etching technique. The dentin/resin interface was studied in transmission (TEM) and scanning (SEM) electron microscope. In TEM sixteen teeth were investigated, each adhesive was applied in four teeth. Under SEM forty teeth were studied, each adhesive was applied in ten teeth. The obtained results demonstrated that all the dentine adhesives studied were able to penetrate into dentinal tubules and to form a hybrid layer with the demineralized intertubular and peritubular dentine. There was no substantial difference in morphology of the dentine/resin interface between the techniques studied. Our results suggest that the hybrid layer function of all four adhesives might be of the same quality.