Effect of Adhesive System Type and Tooth Region on the Bond Strength to Dentin

Purpose: This study evaluated the bond strength of two etch-and-rinse adhesive systems (two- and three-step) and a self-etching system to coronal and root canal dentin. Materials and Methods: The root canals of 30 human incisors and canines were instrumented and prepared with burs. The posts used for luting were duplicated with dual resin cement (Duo-link) inside Aestheti Plus #2 molds. Thus, three groups were formed (n = 10) according to the adhesive system employed: All-Bond 2 (TE3) + resin cement post (rcp) + Duo-link (Dl); One-Step Plus (TE2) + rcp + Dl; Tyrian/One-Step Plus (SE) + rcp + Dl. Afterwards, 8 transverse sections (1.5 mm) were cut from 4 mm above the CEJ up to 4 mm short of the root canal apex, comprising coronal and root canal dentin. The sections were submitted to push-out testing in a universal testing machine EMIC (1 mm/min). Bond strength data were analyzed with two-way repeated measures ANOVA and Tukey's test (p 0.05). Results: The relationship between the adhesives was not the same in the different regions (p 0.05). Comparison of the means achieved with the adhesives in each region (Tukey; p 0.05) revealed that TE3 (mean ± standard deviation: 5.22 ± 1.70) was higher than TE2 (2.60 ± 1.74) and SE (1.68 ± 1.85). Conclusion: Under the experimental conditions, better bonding to dentin was achieved using the three-step etch-andrinse system, especially in the coronal region. Therefore, the traditional etch-and-rinse three-step adhesive system seems to be the best choice for teeth needing adhesive endodontic restorations. Keywords: bond strength, push-out test, coronal dentin, root canal dentin, dental adhesives