This study evaluated the repair bond strengths of ceramic and hybrid ceramic CAD/CAM restorations following bioactive‐glass, silica‐coated alumina, and aluminum oxide surface treatments. Shear bond strength (SBS) tests, surface roughness, and scanning electron microscopic (SEM) evaluations were performed on 180 specimens (7×12×2 mm^3 and 5×5×3 mm^3, respectively) of ceramic (IPS Empress) and hybrid ceramic (Cerasmart270) blocks. Samples were thermocycled (5°C–55°C, 5000 cycles) and silica‐coated alumina, Al₂O₃, or bioactive‐glass were used for surface conditioning. Resin composite was applied on substrate using two‐ (Tokuyama Universal) or one‐bottle (G‐Premio) universal adhesives, combined with the same brand universal shade composites (Omnichroma, Essentia Universal). SBS values were measured using a universal testing machine; failure types were analyzed using a stereomicroscope. Surface roughness was assessed with a profilometer, followed by SEM. Statistical analysis included ANOVA, Tukey HSD, and Fisher's Exact tests. The highest mean SBS values were observed for ceramics in conjunction with two‐bottle universal adhesives. No statistically significant differences were found in the SBS values for different surface conditioning treatments except for hybrid ceramic conditioned with Al₂O₃. Bioactive‐glass and silica‐coated alumina caused similar surface roughness as indicated by the SEM images. A surface conditioning method and an adhesive system are both essential for hybrid ceramic repairs, while the adhesive system was more critical for ceramics.
Gençer et al. (Fri,) studied this question.