Effect of Surface Treatment and Aging on Bond Strength of Composite Cement to Novel CAD/CAM Nanohybrid Composite

Purpose: To evaluate the effect of surface treatments and aging on the bond strength of composite cement to a novel CAD/CAM nanohybrid composite. Materials and Methods: Microtensile bond strength (pTBS) of a dual-curing composite cement (Bifix QM; BQ) to three CAD/CAM restorative materials (Grandio [GR], Vita Enamic EVE], and Lava Ultimate [LU]) was evaluated after different surface treatments. The surfaces of specimens received the following treatments: control (no treatment), sandblasting (SB), SB + silane (Ceramic Bond; CB), hydrofluoric acid (1-IF), HF + CB, TiF4 2 wt/v%, TiF4 2 wt/v% + CB, TiF4 4 wt/v%, and TiF4 4 wt/v% + CB. Half of the specimens in each group were aged. Surface topography and surface roughness were evaluated. Statistical analysis was conducted using ANOVA and Tukey's test. The Weibull analysis was conducted on mu TBS data of aged groups. Results: The mu TBS was significantly affected by the type of CAD/CAM material, type of treatment, and aging (p < 0.001). Silane application significantly improved the mu TBS (p < 0.05). The mu TBS decreased significantly with aging (5000 thermocycles) (p < 0.05). BQ cement resulted in the highest mu TBS to GR treated with TiF4 2% wt/v + CB compared to the other groups (p < 0.05). Aged GR/BQ treated with TiF4 2% wt/v + CB had the highest predicted mu TBS (19 MPa). Conclusion: TIF4 2% wt/v followed by silane application enhanced the adhesion of GR/BQ and LU/BQ systems. On the other hand, HF surface treatment followed by silane application improved the adhesion of the VE/BQ system.