Bond strength of self-etching adhesive systems to deep dentin

Introduction and objective: The self-etching adhesive systems have been widely used by dentists and researchers in the procedures of adhesive dental restorations. The purpose of this study was to evaluate the microshear bond strength of self-etching adhesive systems to deep dentin.Material and methods: Fifty freshly extracted human third molars were prepared using a diamond saw until obtaining flat surfaces of deep dentin(2 mm below the DEJ of central sulcus), wet-abraded with 600-grit SiC paper. The samples were randomly divided into five groups (n = 10)according to the experimental groups: 1) conventional adhesive Syntac(control), 2) one-step self-etching adhesive One-Up Bond F Plus, 3) one-step self-etching adhesive Hybrid Bond, 4) two-step self-etching adhesive AdheSE – bonded to Tetric Ceram resin composite; and the 5) two-stepself-etching adhesive Silorane System Adhesive bonded to low shrinkageresin composite Filtek Silorane. The adhesives and the resin compositewere applied according to the manufacturers’ instructions, and using aTygon tubing mold. The samples were stored in distilled water at 37±2oC for one week. Microshear bond strengths were determined using a Zwick universal testing machine at a crosshead speed of 0.5 mm/minute.Results: The results obtained in MPa (SD) were statistically analyzed(Anova and Tukey test, p < 0.05), and showed the following results: 2)25,5 (4,4); 1) 24,9 (5,3); 3) 22,4 (8,1); 4) 21,5 (4,4) and 5) 18,1 (7,2).There was statistically significant variation between groups 2 and 5;which did not show difference to the other groups tested. Conclusion:The Silorane System Adhesive and the low shrinkage resin composite Filtek Silorane showed similar bond strength to Syntac, Hybrid Bond and AdheSE – bonded to Tetric Ceram resin composite; however, being lower than One-Up Bond F Plus bonded to Tetric Ceram. Regarding the bond strength, the results suggest that self-etching adhesive systems can be a good alternative in the procedures of adhesive dental restorations to deep dentin.