Effect of Resin Luting Systems and Alumina Particle Air Abrasion on Bond Strength to Zirconia.

This study aimed to evaluate the effect of different primer/resin luting agent combinations and alumina air abrasion on the adhesion to zirconia. Eighty blocks (4x4x3 mm) of Lava Frame Zirconia (3M ESPE) were produced and randomly assigned into eight groups (n=10) according to two zirconia surface treatments (untreated or air abrasion with 50-mum alumina particles) and four luting systems (SU: Scotchbond Universal/RelyX Unicem 2; ZP: Z-Prime Plus/Duo-link Universal; MB: Monobond Plus/Variolink II; and AP: Alloy Primer/ED Primer II/Panavia F 2.0). After the conditioning and primer applications, resin luting agents were manipulated and applied on the zirconia, using a matrix, to form a cylinder (2 mm in diameterx2 mm high), followed by photoactivation for 40 seconds. After that, the specimens were stored in distilled water (37 degrees C) for 120 days and then submitted to shear bond strength testing, followed by failure mode evaluation under an optical microscope (30x). A two-way analysis of variance and Tukey test (alpha=0.05) were used for data analysis. Alumina air abrasion (Al) promoted higher bond values for the three luting systems, except for SU, which showed the best results without air abrasion, while with air abrasion, Al-SU, Al-ZP, and Al-MB presented higher values compared to Al-AP. We concluded that the alumina air abrasion of zirconia surfaces seemed to be dispensable for the SU group, while air abrasion (topographical alterations) enhanced the adhesion of the ZP, MB, and AP groups.