Comparison of Mechanical and Optical Properties of Multilayer Zirconia After High-Speed and Repeated Sintering

This study aims to investigate the mechanical and optical properties of two different multilayer monolithic zirconia materials after the high-speed and repeated sintering process recommended by the manufacturers. In this study, specimens with a diameter of 12 mm and a thickness of 1 mm were fabricated using KATANA Zirconia YML (Kuraray Noritake) and IPS e.max ZirCAD Prime (Ivoclar Vivadent) multilayer zirconia. These specimens were processed with two different protocols to be used in the sintering process: high-speed and conventional sintering. Both protocols were repeated three times, after which the changes in the mechanical, microstructural and optical properties of the specimens were compared and analyzed. According to the biaxial flexural strength result, KATANA Zirconia YML (840.84 MPa) showed higher biaxial flexural strength compared to IPS e.max ZirCAD Prime (627.64 MPa) after repeated high-speed sintering. When the optical properties were analyzed, the translucency parameters of the IPS e.max ZirCAD Prime block were reliable in certain protocols. A comparison of mechanical and optical properties after repeated and high-speed sintering reveals that both materials offer advantages for different application requirements. The high biaxial flexural strength of KATANA Zirconia YML is more suitable for applications requiring strength. The homogeneous translucency of IPS e.max ZirCAD Prime is esthetically and optically safer for high-speed and repeated sintering processes.