Microtensile Bond Strength of CAD/CAM Resin Blocks to Dual-Cure Adhesive Cement: The Effect of Different Sandblasting Procedures.

PURPOSE: To investigate the effect of sandblasting powder particles on microtensile bond strength (μTBS) of dual-cure adhesive cement to CAD/CAM blocks.

MATERIALS AND METHODS: CAD/CAM blocks (Cerasmart, VITA, and LAVA) were cut in slabs and divided into groups: group 1, no sandblasting; group 2, sandblasted with 27-μm Al2 O3 ; group 3, sandblasted with 30-μm CoJet; group 4, sandblasted with 50-μm Al2 O3 . After sandblasting, all specimens were silanized and luted using dual-cure adhesive cement (G-CEM LinkForce). After 24 hours, bonded specimens were cut into 1 ± 0.2 mm2 sticks, and μTBS values were obtained (N = 30). Additionally, 132 CAD/CAM block sections were prepared for surface roughness testing and scanning electron microscopy (SEM) evaluations. Results were analyzed using Kruskal-Wallis One-way ANOVA and Dunn's Post Hoc Test (p < 0.05).

RESULTS: Group 1 exhibited significantly lower μTBS than the other groups (p < 0.05). The highest bond strength values were obtained from group 4 (p > 0.05). For LAVA, μTBS values of specimens that were sandblasted with 50-μm Al2 O3 powder were significantly higher than 30-μm-SiO2 and 27-μm Al2 O3 (p < 0.05).

CONCLUSIONS: The sand particles investigated (27-μm Al2 O3 , 30-μm SiO2 , or 50-μm Al2 O3 ) did not significantly affect μTBS results of CAD/CAM blocks for Cerasmart and VITA, although the results changed significantly for LAVA. The ideal bond protocol for CAD/CAM blocks is specific to the material used.