Objectives: This study aimed to assess the effect of various surface treatments on the bond strength of ceramic restorations constructed with CAD/CAM technology. Materials and methods: A total of sixty ceramic discs were manufactured using CAD/CAM technology with dimensions (8×3mm). Discs were categorized into two main groups (n=30) based on type of ceramic used (Zirconia (Z) and Vita enamic (V)). Each group was subdivided into three subgroups depending on aluminum oxide particles size used for sandblasting (40, 80 and 110 μm) then Monobond® N primer was applied to all discs. Sixty composite resin discs (4 mm×3 mm) were fabricated and adhered to ceramic discs using adhesive resin cement (Multilink®N). All specimens were kept for three months in a water bath at 37°C, then 3000 thermal cycles (5–55°C). Using a universal testing machine, the shear bond strength was recorded. To examine the failure mode, a scanning electron microscope (SEM) was used. The data were tabulated and statistically analyzed.
Results: The results of this study revealed statically significant differences in SBS between the most of groups (P<0.05). V110 μm group demonstrated the highest SBS, followed by the V80 μm group, and there was a significant difference between both groups (p = 0.045). There was a statistically significant difference between Z40 μm group compared to the other two groups (Z80 and Z110 μm). The lowest mean SBS value was observed for the Z40 group.

Conclusions: Different size of aluminum oxide particles affected the SBS to CAD/CAM fabricated ceramic materials.