Abstract: Objectives: To compare the interaction of dentin with an acetone-based and an ethanol/water-based adhesive systems. Methods: A total of 24 intact young human premolars extracted for orthodontic reasons were used. The enamel of occlusal surfaces of these premolar teeth was removed and dentin was exposed. The specimens were split into 2 groups, 1 group for each bonding agent: acetone-based adhesive system (Prime Bond NT, PB) and alcohol-water-based (Single Bond2, SB2). Dentin adhesive systems were bonded to dentin according to manufacturers’ instructions, composite layers were built up incrementally. Microtensile bond strength was determined, and the results were statistically analyzed using t-test with a 5% level of significance. SEM and LCSM investigation were performed for the qualitative evaluation of resin-dentin hybridization. Results: There were no statistically significant differences in bond strength between the adhesive systems. Both bonding systems could infiltrate well into the peritubular- and intratubular. Hybrid layer and resin tags were formed. Hybrid layer of SB2 group was thin and rough, resin tags were long. Conclusion: Different solvent content had no influence on the microtensile bond strength of total-etch dentin adhesive systems.

Key words: Total-etch dentin adhesive system, Microtensile bond strength , Bonding interface , SEMLCSM