Shear bond strength and SEM Evaluation of glass ceramics bonded to immediately sealed dentine using universal adhesive

Immediate dentin sealing (IDS) has been proposed as an alternative to delayed dentin sealing (DDS), a procedure in which adhesive resin is applied immediately to freshly cut dentin following tooth preparation.Materials and methods:The occlusal surfaces of 50 freshly extracted human teeth were prepared flat to expose the midcoronal dentin surface. Then, all prepared teeth were allocated randomly according to dentin sealing protocol into two main groups; Group (DDS): Delayed Dentin Sealing and Group (IDS) Immediate Dentin Sealing. For (DDS) group, the prepared occlusal surfaces were covered directly by a layer of provisional restoration. After 1week, provisional restorations were removed and dentin was cleaned. For (IDS) group, universal dentine bonding adhesive was applied immediately to freshly cut dentine, then light cured, and temporarization was performed as in DDS group. Fifty glass ceramic discs were fabricated from Lithium disilicate block. After ceramic surface treatment, discs were bonded to dentine of both groups. Then, all specimens were thermo-cycled before being subjected to shear bond strength test. Scanning electron microscope (SEM) was used to examine dentin-cement-ceramic junction and mode of failure. Results: Specimens with IDS protocol revealed higher shear bond strength than DDS protocol. SEM revealed that Adhesive failure was recorded as the most common pattern in IDS group, while in DDS group showed predominantly mixed failure at the dentine side. Conclusion:The findings of current study suggest that, immediate dentine sealing with universal adhesive proved to be a reliable strategy for bonding glass ceramic restorations on prepared teeth with exposed dentin.