Bonding of simplified adhesives to bovine root dentin

Objectives: To evaluate the push-out strength of three simplified adhesive systems to bovine root dentin. The hypothesis was that the application of the additional layer of a low-viscosity bonding resin improves the bond strength of all-in-one Xeno adhesive. Methods: Thirty bovine teeth were cut at 16 mm, beginning in the most apical portion of the root throw the coronal portion. The roots were prepared at 12 mm using the custom post drill (FRC Postec Plus, Ivoclar). Each specimen was included in a resin acrylic from the 4 mm apical portion of the root, using a adapted surveyor, and the specimens were divided into three groups, according to the adhesive system, which were applied following the manufacturer's instructions: (Gr1) Xeno; (Gr2) Xeno + ScotchBond Multi-Purpose Plus Adhesive; (Gr3) One Step Plus. The post was imprinted with addition silicon and reproduced in resin cement (Duolink). The specimens were treated with the adhesive systems and the resin posts were luted.. Each specimen was cut in 4 samples of approximately 1,8 mm in thickness and submitted to the push-out test in a universal testing machine. The bond strength data were submitted to the one-way ANOVA and post-hoc Tukey test (alpha=0.05). Results: the push-out strength (MPa) of Gr2 (2.9±1.2) was statistically higher (P=.0002) than those of Gr1 (1.1±0.5) and Gr3 (1.06±0.5). Gr1 and Gr3 had not difference significant. Conclusion: the application of the additional layer of a low-viscosity bonding resin improved the bond strength of all-in-one Xeno adhesive. The hypothesis was accepted.