The purpose of the study was to evaluate the shear bond strengths (SBS) of two resin cements to intaglio surfaces of zirconia from two manufacturers after three surface treatment methods. Forty zirconia specimens from one manufacturer (Lava, 3M ESPE) and 40 zirconia specimens from another manufacturer (Cercon, Dentsply), each with system-specific intaglio surfaces, were randomly divided into four treatment groups (20 samples per group, 10 for each manufacturer): no treatment (No_T), sandblasting with 50µm Al2O3 (S_50), sandblasting with 110µm Al2O3 (S_110), and Rocatec silica coating and silanization (ESPE-Sil, 3M ESPE) (Roc). A 5-mm metal ring was fixed upon the zirconia and was filled with one of two different resin composite cements (RelyX Unicem, 3M ESPE and Panavia F 2.0, Kuraray). Samples were stored in distilled water at 37°C for 7 days; SBS was evaluated using a universal testing machine. Values were calculated in MPa and the data were analyzed by ANOVA and Tukey HSD test (P < .05). In the Lava specimens, the three surface treatment methods tested did not increase the bond strength of Panavia compared to the control group (P = .195); using RelyX Unicem, S_50 and Roc, mean SBS values were significantly higher than values for No_T (S_50 P = .0048; Roc P < .001). For Lava surfaces treated with Rocatec, there was a statistically significant difference between the two luting cements used (Unicem 11.39 ± 2.19; Panavia 8.56 ± 1.17; P = .002). Regarding the Cercon specimens, there was a significant difference between the Unicem and the Panavia control groups (No_T Unicem 1.48 ± 1.19, No_T Panavia 4.60 ± 2.75, P = .004). In conclusion, all surface treatments increased the bond strength of RelyX Unicem resin cement to both zirconia substrates. No statistically significant changes were found using Panavia on Lava. Sandblasting with 110µm Al2O3 provided the highest bond strength for Panavia on Cercon.
