Comparison of Bond Stability Between Dual-Cure Resin Cements and Pretreated Glass-Infiltrated Alumina Ceramics

Abstract

To evaluate the bond stability of resin cements used for luting alumina-based all-ceramic dental restorations. Although different pretreatments may be applied on alumina to improve bond strengths, any previous study investigated the bond stability of resin-based cements luted to laser-irradiated alumina. 64 sintered, glass-infiltrated alumina blocks were sandblasted and randomly assigned to the following subgroups: 1. no additional treatment (NT); 2. Rocatec (Roc); 3. Nd:YAG laser (L); and 4. Nd:YAG laser plus Rocatec (LRoc). Composite samples were bonded to conditioned ceramics using two different resin based cements: a self-etching adhesive cement-Panavia F (PF) and a self-adhesive resin cement-RelyX Unicem (RXU). After 24 h, bonded specimens were cut into microtensile sticks (1 ± 0.1 mm(2)). One-half of the beams were loaded in tension until failure. The remaining one-half was immersed in 10%-NaOCl aqueous solution (NaOCl(aq)) for 12 h before testing. ANOVA and Student-Newman-Keuls tests were run (P < 0.05). Failure mode was recorded. Ceramic topography was SEM-analyzed. After 24 h, L-sticks achieved the highest MTBS despite the cement type, whereas NT-samples recorded the lowest values. After NaOCl(aq) immersion bond strengths decreased except for RXU luted to NT-alumina. PF luted to L- and LRoc-samples, and RXU luted to L-sticks attained the highest bond strength. Nd:YAG laser irradiation improved bond strength between alumina ceramics and resin cements (PF or RXU). Chemical challenging impaired adhesion, mainly through resin matrixes and silane coupling degradation. Laser-treated specimens remained with the highest bond strength.