Evaluation of the effects of thermal changes on the bond strength between zirconia framework and veneering ceramic during the firing process

Authors : Yeşim ÖLÇER US, Betül TUNCELLİ

Pages : 108-114

Doi:10.26650/eor.2023978293

View : 26 | Download : 57

Publication Date : 2023-05-31

Article Type : Research Paper

Abstract :Purpose The aim of this in-vitro study was to evaluate the effect of thermal changes to shear bond strength during the firing process of veneering porcelain on a zirconia framework. Materials and Methods Single yttria-stabilized tetragonal zirconia polycrystal insert ignore into journalissuearticles values(Y-TZP); framework ceramic insert ignore into journalissuearticles values(Kavo Dental GmbH); and three different types of veneering ceramics insert ignore into journalissuearticles values(IPS e.max Ceram, Vita VM9, and GC Initial Zr-FS); were used. One-hundred-twenty standard disc-shaped samples were prepared from zirconia blocks by using a CAD/CAM system insert ignore into journalissuearticles values(Kavo Everest);. Four different cooling processes insert ignore into journalissuearticles values(maximum, 25°C/min, 50°C/min and 75°C/min); were applied to the veneering ceramics and the shear bond strength insert ignore into journalissuearticles values(SBS); test was performed. Ceramic surfaces were investigated by using scanning electron microscopeic insert ignore into journalissuearticles values(SEM);. The possible occurrence of a t–m transformation of zirconia was evaluated by X-Ray Diffraction insert ignore into journalissuearticles values(XRD);. Two-way analysis of variance, Bonferroni correction and paired comparisons were used for statistical analysis. Results The main effects of veneering ceramics on shear bond strength were found to be significant insert ignore into journalissuearticles values(p=0.042);. The mean shear bond strength values differ according to the cooling process insert ignore into journalissuearticles values(p<0.001);. The monoclinic phase ratio increased in groups with fast cooling process. Conclusion The thermal changes during the firing process of veneering porcelain on a zirconia framework influenced the shear bond strength of the all-ceramic bilayered system. A slow cooling process provided higher strength for bilayer ceramic samples.
Keywords : Zirconia, Veneering ceramic, CAD CAM, Bond strength, Cooling process