Assessment of resin-dentin interfacial morphology of two ethanol-based universal adhesives: A scanning electron microscopy study

OBJECTIVE: The objective of this study was to assess the resin-dentin interfacial morphology created by two universal adhesives using scanning electron microscopy (SEM). MATERIALS AND METHODS: The occlusal surfaces of ten (n = 5) molars were reduced to expose a flat surface of dentin. Two universal adhesives, Scotchbond Universal Adhesive and Tetric N-Bond Universal, were independently applied to air-dried dentin. Light-cured resin-based composite restorative materials were used to incrementally build a composite “buildup.” The specimen was sectioned mesiodistally to expose the resin-dentin interface. The inner surfaces of the specimens were polished. Samples were immersed in hydrochloric acid and then rinsed using distilled water. This was followed by immersion of the samples in 1% sodium hypochlorite solution. Then, samples were thoroughly rinsing with distilled water. Dehydration of samples was performed using ascending concentration of ethyl alcohol. Prepared samples were observed SEM at magnifications ×1500 and x4000. RESULTS: Both universal adhesives could penetrate dentin-forming well-defined resin tags, lateral branches as well as a uniform hybrid layer. CONCLUSIONS: Two tested universal adhesives applied in self-etch mode can infiltrate into dentin-producing high-quality interfacial morphology. Similar interfacial morphology may be due to the similarity in composition and application mode.