Eva Jerman1, Felicitas Wiedenmann2, Marlis Eichberger2, Axel Reichert3, Bogna Stawarczyk2. 1. Department of Prosthetic Dentistry, University Hospital, Ludwig-Maximilians University, Goethestrasse 70, 80336 Munich, Germany. Electronic address: eva.jerman@med.uni-muenchen.de. 2. Department of Prosthetic Dentistry, University Hospital, Ludwig-Maximilians University, Goethestrasse 70, 80336 Munich, Germany. 3. Research & Development, Amann Girrbach AG, Herrschaftswiesen 1, 6842 Koblach, Austria.
Abstract
OBJECTIVE: To investigate the influence of high-speed and conventional sintering on the flexural strength (FS) of three zirconia materials initial and after artificial aging. METHODS: Milled zirconia specimens (3Y-TZP: ZI and Zolid; 4Y-TZP: Zolid HT+; Amann Girrbach AG; N = 288, n = 96/group) were sintered in a high-speed sintering protocol (final temperature 1580 °C, n = 48/subgroup) or a conventional sintering protocol (control group, final temperature 1450 °C, n = 48/subgroup). FS was tested initially and after artificial aging (10 h in an autoclave or 1,200,000 chewing cycles; n = 16/subgroup). Univariate ANOVAs, post-hoc Scheffé, partial eta-squared, Kolmogorov-Smirnov-, Kruskal-Wallis- and Mann-Whitney-U-test were performed (p < 0.05). RESULTS: ZI showed the highest and HT+ the lowest FS, regardless of the sintering protocols and aging regimens (p < 0.001). High-speed sintered HT+ showed higher initial FS than the control group (p < 0.001). ZI (p < 0.001-0.004) and Zolid (p < 0.001-0.007) showed higher FS after thermo-mechanical aging. High-speed sintered HT+ showed higher FS in the initial stage (p < 0.001). The Weibull modulus of the three thermo-mechanically aged materials was negatively influenced by high-speed sintering. SIGNIFICANCE: As shorter sintering times represent a cost and time efficient alternative, high-speed sintering is a valid alternative to conventional sintering protocols.
OBJECTIVE: To investigate the influence of high-speed and conventional sintering on the flexural strength (FS) of three zirconia materials initial and after artificial aging. METHODS: Milled zirconia specimens (3Y-TZP: ZI and Zolid; 4Y-TZP: Zolid HT+; Amann Girrbach AG; N = 288, n = 96/group) were sintered in a high-speed sintering protocol (final temperature 1580 °C, n = 48/subgroup) or a conventional sintering protocol (control group, final temperature 1450 °C, n = 48/subgroup). FS was tested initially and after artificial aging (10 h in an autoclave or 1,200,000 chewing cycles; n = 16/subgroup). Univariate ANOVAs, post-hoc Scheffé, partial eta-squared, Kolmogorov-Smirnov-, Kruskal-Wallis- and Mann-Whitney-U-test were performed (p < 0.05). RESULTS: ZI showed the highest and HT+ the lowest FS, regardless of the sintering protocols and aging regimens (p < 0.001). High-speed sintered HT+ showed higher initial FS than the control group (p < 0.001). ZI (p < 0.001-0.004) and Zolid (p < 0.001-0.007) showed higher FS after thermo-mechanical aging. High-speed sintered HT+ showed higher FS in the initial stage (p < 0.001). The Weibull modulus of the three thermo-mechanically aged materials was negatively influenced by high-speed sintering. SIGNIFICANCE: As shorter sintering times represent a cost and time efficient alternative, high-speed sintering is a valid alternative to conventional sintering protocols.