Influence of fatigue load on various adhesive resin luting agents in a zirconia-reinforced lithium silicate ceramic bonded to dentin.

PURPOSE: To examine fatigue failure load value of etch-and-rinse and self-adhesive luting systems used to bond ZLS to dentin. Moreover, this study seeks to evaluate whether the application of unfilled resin on silanated ceramic intaglio surface could improve fatigue failure load value. METHODS: Vita Suprinity (VS) blocks were sectioned into a cylindrical shape (5 mm in diameter and 1.5 mm in height). All VS were crystallized, and bonded surfaces were either treated with Heliobond (HB) application after silanization or without application of HB. Each VS was cemented to each flat occlusal dentin surface of the extracted human molar, following the adhesive luting systems: Optibond FL (FL) with Nexus3 (NX3), RelyX Unicem (UC), and Maxcem Elite (ME). 24-hour mean fatigue failure load was determined using a staircase approach (500,000 cycles, 20 Hz, initial load = 844 N, step size = 42 N). Representatives of failed specimens were evaluated by a scanning electron microscope (SEM). RESULTS: The Behrens-Fisher T-test revealed that ZLS cemented to dentin using self-adhesive resin luting cements (UC and ME) had a statistically significantly lower mean fatigue failure load value than etch-and-rinse resin luting cement (FLNX3) (alpha= 0.05). Meanwhile, the HB application groups did not achieve a statistically significant difference in fatigue failure load value when compared to non-application groups (alpha= 0.05). CLINICAL SIGNIFICANCE: Fatigue strength evaluation of ZLS bonded to dentin suggested that self-adhesive luting systems may not be the material of choice compared to a 3-step etch and rinse luting system.