Objective: To evaluate the effect of CAD/CAM surface treatments and different adhesives on the shear bond strength (SBS) of a CAD/CAM composite to dentin.

Materials and Methods: In total, 120-flat dentin surfaces were prepared, and divided into 12 groups (n=10) according to: 1- CAD/CAM surface treatment, and 2: Type of adhesive. A total of 120 CAD/CAM composite rods (2mmx2mmx4mm) were prepared, and sandblasted. The rods were left without further treatment, ultrasonically cleaned in distilled water, or acid etched using 35% phosphoric acid. The dual- and self-cured adhesives were applied to dentin, in etch-and-rinse or self-etching modes and the rods were cemented using dual-cured resin cement. The SBS test was run at a crosshead speed of 0.5 mm/min until failure. Data were analyzed using Two-Way ANOVA/Tukey test, P=0.05.

Results: Factors “surface treatment", “adhesive" and “surface treatment x adhesive" had significant effect on SBS (P0.05). Sandblasting had the highest significant SBS among surface treatments (P<0.05). Self-cured adhesive showed higher SBS compared to dual-cured adhesive in etch-and-rinse mode (P<0.05). Mixed failure was the predominate failure (59.2%).

Conclusion: Sandblasting improved the SBS of a CAD/CAM composite to dentin. The use of dual-cured universal and self-cured adhesives in their simplified self-etching approach is preferrable.