Abstract
The purpose of this study was to analyze the interfacial morphology between dentin and a single-component dental adhesive system (Single Bond Universal, 3M ESPE), applied with or without preliminary phosphoric acid etching. In this study, 20 cavities were prepared in extracted teeth and restored with composite resin, using the tested adhesive. The axial sections were observed by scanning electron microscopy. When the adhesive was applied without etching, the hybrid layer was thin and not uniform. The resin tags could rarely be observed within the tubules. Preliminary acid etching of dentin resulted in thicker hybrid layers and augmented resin tags. However, for the tested adhesive, preliminary etching with phosphoric acid did not seem to significantly improve the quality of the dentin sealing. The EDX determination using the Line mode of the elements variation indicated a more severe drop of calcium in dentin when preliminary etching with phosphoric acid was applied comparing to the situations when the adhesive was applied in self-etching procedures. Keywords: bonding system, phosphoric acid, hybrid layer, dentin, self-etch, total-etch