Abstract Objectives This study evaluated the immediate and 6-month resin–dentin μ-bond strength (μTBS) of one-step self-etch systems (Adper Prompt L-Pop AD 3M ESPE; Xeno III XE Dentsply De Trey; ...iBond iB Heraeus Kulzer) under different application modes. Materials and methods Dentin oclusal surfaces were exposed by grinding with 600-grit SiC paper. The adhesives were applied according to the manufacturer's directions MD, or with double application of the adhesive layer DA or following the manufacturer's directions plus a hydrophobic resin layer coating HL. After applying the adhesive resins, composite crowns were built up incrementally. After 24-h water storage, the specimens were serially sectioned in “ x ” and “ y ” directions to obtain bonded sticks of about 0.8 mm2 to be tested immediately IM or after 6 months of water storage 6M at a crosshead speed of 0.5 mm/min. The data from each adhesive was analyzed by a two-way repeated measures ANOVA (mode of application vs. storage time) and Tukey's test ( α = 0.05). Results The adhesives performed differently according to the application mode. The DA and HL either improved the immediate performance of the adhesive or did not differ from the MD. The resin–dentin bond strength values observed after 6 months were higher when a hydrophobic resin coat was used than compared to those values observed under the manufacturer's directions. Conclusions The double application of one-step self-etch system can be safety performed however the application of an additional hydrophobic resin layer can improve the immediate resin–dentin bonds and reduce the degradation of resin bonds over time.
To evaluate the use of two alternative modes of application (double-application and placement of a hydrophobic resin coat) compared with the manufacturers' directions on the microtensile bond ...strength (microTBS) of one-step, self-etch systems to enamel and dentin.
Resin composite buildups were bonded to the buccal and lingual ground enamel surfaces and occlusal dentin of third molars using the following adhesives: Xeno III (XE), GBond (GB), Adper Prompt L-Pop (AD) and Clearfil SE Bond (CSE) as the control. The adhesive systems were applied: (1) following the manufacturer's directions (MD), (2) with double-application (DA) or with (3) additional placement of a hydrophobic resin layer (HR) after following the manufacturer's directions. After storage in water (24 hours/37 degrees C), the bonded specimens were sectioned into sticks (0.8 mm2) that were tested until failure at a crosshead speed of 0.5 mm/minute. Data from each substrate were subjected to two-way ANOVA and Tukey's test (alpha = 0.05).
The interaction Adhesive vs. Application mode was statistically significant (p < 0.05) for both substrates. In dentin, XE and GB achieved high microTBS in the HR group (p < 0.05). For AD, the highest microTBS were observed in the DA group (p < 0.05). For enamel, similar microTBS was observed for XE and GB among the three modes of application, while the highest pTBS of AD was observed in the HR group.
The effects of using the double-application and placement of a hydrophobic resin coat on microtensile dentin-bond strength values seem to be effective; however, these techniques in enamel were adhesive-dependent.
