مرکز منطقه ای اطلاع رساني علوم و فناوري - THERMAL COMPATIBILITY OF DIFFERENT ZIRCONIA CORE MATERIALS AND VENEERING CERAMICS

Abstract :

Objective: The purpose of the present investigation was to assess thermal compatibility of different zirconia core materials and veneering ceramics designed for zirconia by measuring the thermal expansion coefficients. Material and Method: Five zirconia core materials (Cercon base, Lava All-Ceramic, Zirkonzahn, Vita In-Ceram 2000 YZ Cubes, and Procera Bridge Zirconia) and seven veneering ceramics (Lava Ceram Veneer, Cerabien ZR, IPS e.max, Vintage ZR, Vita VM9, Zirox, and Cercon Ceram Kiss) were selected for this study. Three disk-shaped specimens (9 × and 4 mm) of each core and veneer material were prepared. The specimens were heated from room temperature to 500 °C at a heating rate of 5 °C/minute using a thermal dilatometer device. The change in thickness of disk shaped specimens was digitally registered by two sensors strain. The thermal expansion coefficients between 25 and 500 oC were determined according to ISO 9693 standard. Mean values of the thermal expansion coefficients of three specimens were calculated. Results: Thermal expansion coefficients during heating from 25 to 500 °C for veneers were; 8.6 ± 0.5 10^-6/°C for Vintage ZR, 9.7 ± 0.3 10^-6/°C for Cerabien ZR, 10.2 ± 0.4 10^-6/°C for Lava Ceram Veneer, 9.2 ± 0.4 10^-6/°C for Zirox, 9.4 ± 0.6 10^-6/°C for Vita VM9, 10.1 ± 0.6 10-6/oC for Cercon Ceram Kiss, and 10.1 ± 0.7 10^-6/°C for IPS e.max. Thermal expansion coefficients of the cores were 10.3 ± 0.2 10^-6/°C for ZirkonZahn, 11 ± 0.6 10^-6/°C for Vita In-Ceram 2000 YZ Cubes, 10.5 ± 0.1 10^-6/°C for Cercon Base, 11.1 ± 0.6 10^-6/°C for Lava Core and 10.5 ± 0.2 10^-6/°C for Procera Zirconia. Conclusion: Lava Ceram Veneer, Cercon Ceram Kiss, and IPS e.max showed low thermal expansion coefficient mismatch (Δα) with all core materials. Vintage ZR and Zirox showed Δα of higher than 1x10^-6/ °C with all core materials. Cerabien ZR and Vita VM9 revealed different mismatch rates with zirconia cores tested in the study.