Method: occlusal enamel was removed to expose a flat dentin surface. Cavities 4 x 5 x 4 mm (length x wide x depth) were prepared with diamond burs on occlusal dentin. The restorations (n = 6) were placed using bulk fill technique, according to the manufacturer’s instructions: XP Bond + Surefil SDR Flow, Dentsply (S); Tetric N-Bond + Tetric EvoCeram Bulk Fill, Ivoclar Vivadent (T) and Universal Bond + Filtek Bulk Fill, 3M ESPE (F). The control group was OptiBond FL + Herculite Classic, Kerr (H) applied incrementally (oblique technique). Teeth were stored for 24 h in distilled water at 37 °C and then prepared for microtensile testing. Bonded beams of approximately 1 mm² were obtained and tested in tension at 0.5 mm/min. Results were analyzed by one-way ANOVA and Tukey test (a=0.05).
Result: means ± standard deviations for bond strengths (MPa) were: H: 58.7±17.0; S: 52.3±14.1; T: 51.5±13.0 and F: 27.1±11.0. There was no statistical difference among H, S and T. F presented the lowest dentin bond strength.
Conclusion:
the bond strength of bulk fill restorative systems demonstrated to be as effective as incremental technique. Etch-and-rinse adhesive systems used with bulk fill composites (S and T) yielded higher bond strength than that presented for the self-etching system (F).