Effects of Adhesive/Silane Application on Bond Durabillity to LS₂ Ceramic

Objectives: The aim of this study was to test the effects of different adhesive protocols and silane application on the adhesive durability to a Lithium Disilicate (LD) reinforced glass ceramic using microshear bond strength test.
Methods: Forty LD disks of 13mm diameter (E.max Press, Ivoclar Vivadent) were used in the present study. They were wet-polished with SiC papers, etched with 9.5% HF for 20s and cleaned in an ultrasonic bath. Disks were randomly assigned into 4 groups according to the adhesive/silane protocol: G1 – silane application only (SIL); G2 – silane application followed by adhesive (SILXP - XP Bond, Dentsply De Trey). G3 – silane-containing adhesive (SBU - ScotchBond Universal, 3M Oral Care); G4 - silane application followed by silane-containing adhesive (SILSBU). Afterwards, specimens were divided into 2 subgroups, according to the water-storage time, 24 hours or 12 months. Tygon tubes of 1-mm diameter and 3-mm height were used for application of a low-viscosity composite resin. Four resin composite cylinders were made on each ceramic disk and light-cured for 40s. Microshear bond strength (SBS) test was carried on a universal testing machine (1mm/min).
Results: Results were statistically analyzed by 2-way ANOVA and Tukey test (p<0.05). After 24 h, the highest SBS values were observed for SILXP and SILSBU. However, after 12 months, SILXP and SILSBU presented a significant reduction in SBS, while the highest SBS were observed for SIL. For SBU, no significant reduction in SBS was observed, however it showed the lowest SBS after 12 months of water-storage.
Conclusions: Regardless of the presence of silane in the composition of SBU, previous silane application is still recommended prior to cementation of LD.