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

Purpose: To assess how sandblasting influences shear bond strength (SBS) between nano-ceramic-resin and two resin cements. Methods: 40 nano-ceramic-resin blocks were divided into two groups (n=20): a control (C) and a test group (S_50) where air abrasion (50 µm, 0.28 MPa,10 s) 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 (α=.01) was used to establish differences between groups, considering SBS as dependent and the type of surface treatment as independent variable. Results: Mean SBS (MPa) obtained for P were 8.68 ± 1.16 for C and 13.91 ± 2.58 for S_50. Sandblasting positively affected (p<0.01) the self-adhesive cement adhesion to nano-ceramic resin. Group C_LP showed 100% of adhesive fractures, while S_50_LP had some cohesive (20%) and mixed fractures (10%). The fracture pattern of group C_LR was 60% cohesive, 20% adhesive and 20% mixed, while group S_50-LR showed 100% of cohesive failure. Conclusion: Sandblasting is suggested when luting nano-ceramic resin with LP.