Comparison of Retention of Zirconium Oxide Ceramic Copings with A 24-Degree Convergence Angle with Four Different Types of Cement

The aim of this study was to compare the retention of zirconium oxide ceramic copings at a 24 degree convergence angle with four different types of cement. In this experimental study, 40 first and second premolars were randomly divided into four groups (n = 10). After preparing the specimens, zirconia copings were cemented using RelyX Ultimate, Panavia F, resin-modified GI and zinc phosphate cements under a 5-kg force, followed by thermocycling (3000 rounds 5-55°C) for 24 hours in water with pH = 7 and a temperature of 37°C. Then the copings were separated under a tensile strength in an electromechanical universal testing machine at a strain rate of 0.5 mm/min and their retention was measured. Data were analyzed using SPSS 25 with Kruskal- Wallis and Mann-Whitney tests. The means and standard deviations of retention in the RelyX Ultimate, Panavia F, resin-modified GI and zinc phosphate groups were 7.17 ± 1.13, 4.26 ± 0.37, 2.72 ± 0.43 and 2.3 ± 0.57 MPa, respectively, with significant differences between the groups (p value < 0.001). Based on the results of this study, the retention of ceramic copings of zirconium oxide at a 24-degree convergence angle was different in terms of the cement type, with RelyX Ultimate cement exhibiting the highest retention.