In vitro Comparison of Shear Bond Strength of Various Cements for Zirconia Crowns.

Objective: The aim of this in vitro study was to compare the shear bond strengths of various cements for zirconia crowns and assess the influence of different luting agents on the bond strength.

Materials and methods: Thirty extracted maxillary premolars were mounted in acrylic molds, with the occlusal enamel removed to expose the dentin. Thirty zirconia blocks (2 mm × 3 mm × 5 mm) were milled from Sagemax zirconia, sintered at 1500°C, and sandblasted. The specimens were divided into three groups (n = 10): Group I (RelyX Universal Cement), Group II (G-Cem LinkForce), and Group III (Panavia SA Cement Plus). After cementation, specimens underwent 2000 thermal cycles (5°C to 55°C) and were tested for shear bond strength using a universal testing machine. The maximum load was recorded, and failure modes were examined under a stereomicroscope. Statistical analysis was performed using Kruskal-Wallis ANOVA and the Mann-Whitney U-test (P < 0.05).

Results: No significant difference (P = 0.630) in bond strength was found between the groups. The mean bond strengths were group I (11.8 MPa), group II (11.5 MPa), and group III (12.4 MPa).

Conclusion: All three cement types provided reliable bond strength for zirconia crowns, with Panavia SA Cement Plus slightly outperforming the others. However, the differences in bond strength were not clinically significant. This study suggests that all three luting agents are viable options for cementing zirconia crowns.