Does sandblasting improve bond strength between nano-ceramic resin and two different luting composites?

Purpose: To assess the influence of a sandblasting surface treatment on the shear bond strength (SBS) between a recently introduced Resin Nano-Ceramic (RNC) CAD/CAM material and two resin cements. Methods: 40 RNC blocks were divided into two groups (n=20): a control (C) and a test group (S_50) to which air abrasion (50 \u3bcm, 0.28 MPa, and 10s) was applied. Each group was divided into two subgroups (n=10) according to the applied luting material: a self-etch dual-cure resin cement (LP) and a dual-cure resin cement (LR). SBSs were determined with a universal testing machine at a crosshead speed of 0.5 mm/min. Fracture patterns were evaluated by a stereomicroscope (25x) and classified into adhesive, cohesive and mixed. One-way ANOVA test (\u3b1=.01) was used to establish differences between groups, considering SBS as dependent and the type of surface treatment as independent variable. Results: Mean SBS values (MPa) and standard deviations (SD) for the experimental groups were: [C-LP]: 8.68 (1.16); [C-LR]: 15.32 (3.93); [S_50-LP]: 13.91 (2.58); [S_50-LR]: 15.77 (4.12). A statistically significant difference (p<0.001) was found between [C-LP] and the other three groups. Sandblasting positively affected (p