Eva Jerman1, Nina Lümkemann1, Marlis Eichberger1, Christian Zoller2, Steffen Nothelfer2, Alwin Kienle2, Bogna Stawarczyk3. 1. Dental Material Unit, Department of Prosthetic Dentistry, University Hospital, Ludwig-Maximilians-University, Goethestrasse 70, 80336 Munich, Germany. 2. Institute for Laser Technologies in Medicine and Metrology, Ulm, Germany. 3. Dental Material Unit, Department of Prosthetic Dentistry, University Hospital, Ludwig-Maximilians-University, Goethestrasse 70, 80336 Munich, Germany. Electronic address: bogna.stawarczyk@med.uni-muenchen.de.
Abstract
OBJECTIVES: Testing and comparing of different non-shaded zirconia materials (3Y-TZP, 4Y-TZP and 5Y-TZP) on optical and mechanical properties. MATERIALS AND METHODS: Zirconia materials (N = 320, Opaque O, Translucent T, Extra Translucent ET, High Translucent HT) were investigated on translucency, Martens parameter, biaxial flexural strength, Chevron-Notch-Beam (CNB) fracture toughness (KIC) and grain size. The grain size was analyzed using a scanning electron microcopy (SEM). Univariate ANOVA, post-hoc Scheffé, partial eta-squared, Kolmogorov-Smirnov-, Kruskal-Wallis- and Mann-Whitney-U-tests (p < 0.05) were performed. The reliability of flexural strength was calculated with two-parametric Weibull analysis and 95 % confidence level. RESULTS: The translucency of ET and HT increased with the thermo-mechanical aging (p < 0.001). The zirconia material and aging had no impact on the Martens hardness and the indentation modulus. ET showed the highest flexural strength values after initial and thermo-mechanical aging (p < 0.001 - 0.683). All four materials showed the highest flexural strength after thermo-mechanical aging after 1.2 Mio cycles. Thermo-mechanically (1.2 Mio cycles) aged HT presented the highest Weibull modulus (m = 15.0) regardless of aging. Within initial groups, T (p ≤ 0.001) showed the highest fracture toughness, followed by O (p ≤ 0.001), ET (p < 0.003) and HT (p ≤ 0.001). SIGNIFICANCE: Translucency of ET and HT increases with thermo-mechanical aging. Chevron-Notch-Beam (CNB) is a valid alternative to the single-edge-V-notched beam (SEVNB) method for testing fracture toughness.
OBJECTIVES: Testing and comparing of different non-shaded zirconia materials (3Y-TZP, 4Y-TZP and 5Y-TZP) on optical and mechanical properties. MATERIALS AND METHODS:Zirconia materials (N = 320, Opaque O, Translucent T, Extra Translucent ET, High Translucent HT) were investigated on translucency, Martens parameter, biaxial flexural strength, Chevron-Notch-Beam (CNB) fracture toughness (KIC) and grain size. The grain size was analyzed using a scanning electron microcopy (SEM). Univariate ANOVA, post-hoc Scheffé, partial eta-squared, Kolmogorov-Smirnov-, Kruskal-Wallis- and Mann-Whitney-U-tests (p < 0.05) were performed. The reliability of flexural strength was calculated with two-parametric Weibull analysis and 95 % confidence level. RESULTS: The translucency of ET and HT increased with the thermo-mechanical aging (p < 0.001). The zirconia material and aging had no impact on the Martens hardness and the indentation modulus. ET showed the highest flexural strength values after initial and thermo-mechanical aging (p < 0.001 - 0.683). All four materials showed the highest flexural strength after thermo-mechanical aging after 1.2 Mio cycles. Thermo-mechanically (1.2 Mio cycles) aged HT presented the highest Weibull modulus (m = 15.0) regardless of aging. Within initial groups, T (p ≤ 0.001) showed the highest fracture toughness, followed by O (p ≤ 0.001), ET (p < 0.003) and HT (p ≤ 0.001). SIGNIFICANCE: Translucency of ET and HT increases with thermo-mechanical aging. Chevron-Notch-Beam (CNB) is a valid alternative to the single-edge-V-notched beam (SEVNB) method for testing fracture toughness.
Authors: Rebecca Jungbauer; Christian Kirschneck; Christian M Hammer; Peter Proff; Daniel Edelhoff; Bogna Stawarczyk Journal: Clin Oral Investig Date: 2021-11-18 Impact factor: 3.573