Silanization effect on microtensile bond strength of a self-adhesive luting material to a disilicate-based glass ceramic

ABSTRACT

Introduction: The rehabilitation of teeth by means of ceramic indirect restorations has been widely performed. Previous studies has shown the effectiveness of silane coupling agents on improving the bond strength of the adhesion of resin cements to ceramics; however, some studies question the use of silane. Objective: To evaluate the effect of silane application on the microtensile bond strength of an auto-adhesive luting material to a lithium disilicate glass-ceramic. Material and methods: Two blocks (9x11x4mm) of lithium disilicate glass-ceramic had one of their surfaces polished (# 220, 360, 600 grit silicon-carbide abrasive papers) and cleaned ultrasonically. The ceramic blocks were then divided into two groups according to the surface treatment G1 (control group) etched with 10% hydrofluoric acid for 20s and silane coated; G2 etched with 10% hydrofluoric acid for 20s. After building two blocks of composite resin (Filtek Z350) with the same dimensions of the ceramic blocks, the self-adhesive resin cement (SpeedCEM) was applied directly to the ceramic surface and the resin block was seated on the cement. After storage (24h, 37°C), the ceramic-cement-composite blocks were cut with an Isomet low-speed diamond saw machine producing sticks, which were loaded to failure at a crosshead speed of 0.5 mm/min. The type of fracture was analyzed under an optical microscope. The results were statistically analyzed using the Student t test. Results: The mean microtensile and standard deviations in megaPascals were G1 = 21.32 (± 4.36) and G2 = 16.55 (± 4.92). Statistical analysis showed that the bond strength was not significantly affected by the surface treatment with silane. Most of the fractures occurred within the adhesion zone. Conclusion: The application of silane had no significant effect on the bond strength between lithium disilicate glass-ceramic and self-adhesive resin cement.