Does Sandblasting Improve Bond Strength between Nano-ceramic Resin and Two Different Luting Composites?

Abstract

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 µm, 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 (α=.01) was used to establish differences between groups, considering SBS as dependent and the type of surface treatment as independent variable. 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:Within the limitations of this study, sandblasting of the RNC surface is recommended when the tested self-adhesive resin cement is used for luting, in order to significantly improve bond strength values. For the luting agent LR -associated with a universal adhesive system -satisfactory adhesion values were achieved regardless an air abrasion pre-treatment.

Comparative Study between Resin Nano Ceramic and CAD/CAM Ceramic Regarding Their Fracture Resistance, Microtensile Bond Strength and Fatigue Resistance

“…This might be due to the fact that mechanical sandblasting caused an increase in the irregularity and the surface free energy so increased the bond strength. (15) These results were in consistent with another study which showed that the abrasion process removed contaminated layers and created a rough surface for mechanical retention by the luting agent. Additionally, surface roughening increased the surface area for efficient bonding and could lead to physicochemical changes such as an increase in surface energy and wettability.…”