Bond Strength of Self-Adhesive Cements to Different Treated Indirect Composites

Objectives: To determine the microtensile bond strength of three self-adhesive resin cements and a total-etch resin cement to indirect composite restorations following different surface treatments.

Methods: Composite overlays (Filtek Z250, 3M ESPE) were luted on flat dentin surfaces of extracted human third molars using the following self-adhesive resin cements: Maxcem Elite (KerrHawe), RelyX Unicem (3M ESPE) or G-Cem (GC). The total-etch resin cement RelyX ARC (3M ESPE) was used as the control group. Composite surfaces were ground with 500grit SiC paper and randomly assigned to three different surface treatments: no treatment (NOT), silane application (S) (RelyX Ceramic Primer, 3M ESPE) and silane followed by an adhesive (SA) (Adper Scotchbond 1 XT, 3M ESPE). The bonded assemblies were stored in water (24h, 37 °C) and subsequently prepared for microtensile bond strength testing (µTBS). Beams of approximately 1 mm² were tested in tension at 1 mm/min in a universal tester (Instron 4411). Data were analyzed by Kruskal-Wallis and Mann-Whitney U tests (α=0.05).

Results: Mean µTBS values are shown in the table. Same letter indicates statistically similar µTBS values. A significant influence of the resin cement used was detected (p<0.001). Composite surface treatment did not affect mean bond strengths (p>0.05), although interactions between resin cement and surface treatment were statistically significant (p<0.001).