Influence of silane and heated silane on the bond strength of lithium disilicate ceramics - An in vitro study

Objectives: To evaluate the effect of silane application and silane heat treatment on lithium-disilicate ceramic when bonded to composite resin. Methods: Twelve blocks of lithium-disilicate (LD) ceramic were fabricated and bonding surfaces were etched using 9.5% hydrofluoric acid (90 seconds). Three experimental groups resulted from the various surface treatment combinations, which included, no silane application (NS) (controls), silane application (S) and silane heat treatment (HS) (100°C for 5 minutesutes). Ceramic and composite resin blocks were bonded using an adhesive resin and light cured restorative composite as a luting agent, under standard conditions. A total of 90 specimen sticks (8 x 1mm²) were subjected to micro-tensile bond strength testing. The means of micro-tensile bond strength (μ-tbs) of the study groups were analyzed using t-test and ANOVA. The tested specimens were analyzed for mode of failure using scanning electron microscopy (SEM). Results: The highest μ-tbs value (42.6±3.70 MPa) was achieved for LD ceramics with heat-dried silane. Both silane application and heat treatment of silane resulted in significant (p<0.05) improvements in microtensile bond strength of LD ceramics when bonded to resin composite. Conclusions: The application of silane and its heat treatment showed significant improvement in bond strength of lithium disilicate ceramic when bonded to composite.