Bonding performances of dual-cure adhesive resin cements

Aim: To evaluate the shear bond strength (SBS) of two adhesive dual-cure resin cements to dentin and composite substrates. Methods: Two resin cements (EP, Estecem II Plus, Tokuyama and VAR, Variolink, Ivoclar Vivadent) with dual-cure (DC) or self-cure (SC) polymerization mode and their respective universal adhesives (UB, Universal Bond II and ADH, Adhese universal DC) were used for the study. Regarding the bonding substrates, human molars were cut in half longitudinally to expose dentin, while composite overlays (Estelite Posterior, Tokuyama, 4x4x3mm) were created in two 2mm-incremental layers using a silicone mold. Dentin blocks (D) and composite overlays © were embedded in acrylic resin, leaving one of the surfaces available for bonding. The following adhesive/resin cement combination were used for luting purposes (n=20): 1) UB/DC EP; 2) UB/SC EP; 3) ADH/DC VAR; 4) ADH/SC VAR. Specimens were submitted to SBS test until detachment. Data were statistically analyzed (p<0.05). Results: Cement (ER>VAR), polymerization (DC>SC), substrate (D>C) and the interaction between factors significantly influenced the results. When DC, ER resulted in higher SBS compared to VAR (P<0.05), while no differences were observed between the two cements in SC mode (P=0.81). Conclusions: ER cement combined with the recent SC universal adhesive showed better bonding performance in DC cementation mode, compared to a conventional adhesive cement.