Impact of high-speed sintering on translucency, phase content, grain sizes, and flexural strength of 3Y-TZP and 4Y-TZP zirconia materials

Jansen, Jan Ulrich; Luemkemann, Nina; Letz, Inge; Pfefferle, Regina; Sener, Beatrice und Stawarczyk, Bogna (2019): Impact of high-speed sintering on translucency, phase content, grain sizes, and flexural strength of 3Y-TZP and 4Y-TZP zirconia materials. In: Journal of Prosthetic Dentistry, Bd. 122, Nr. 4: S. 396-403

Abstract

Statement of problem. The lengthy sintering time of zirconia is costly and limits applications. The consequences of shortening the sintering time are mainly unknown. Purpose. The purpose of this in vitro study was to test and compare 2 high-speed sintering protocols and 1 conventional sintering protocol on the translucency, phase content, grain sizes, and flexural strength of 3 zirconia materials. Material and methods. In total, 450 specimens of 3 zirconia materials-two were 3 mol% yttria-stabilized tetragonal zirconia polycrystals (3Y-TZPs), Ceramill ZI and Zolid (ZD), and a 4 mol% yttria-stabilized tetragonal zirconia polycrystal (4Y-TZP), Zolid HT+ (n=150)-and 5 thicknesses (1.0, 1.5, 2.0, 2.5, and 3.0 mm;n=30) were sintered according to 2 high-speed sintering protocols (final temperature 1570 degrees C and 1590 degrees C;n=10) and a reference sintering protocol (1450 degrees C;n=10). After measuring the monoclinic phase content with Raman spectrometry (n=3), the specimens were polished, and translucency was determined. The biaxial flexural strength of specimens with a thickness of 1.0 mm and 1.5 mm was tested (n=20). Statistical evaluation included 1-way ANOVA, the Kolmogorov-Smirnov, Kruskal-Wallis, Mann-Whitney-U, and Spearman-Rho tests and the Bonferroni correction (alpha=.0011). Results. For Zl, the sintering protocols did not affect the translucency or biaxial flexural strength. ZD and HT+ showed significantly lower translucency for high-speed sintering protocols (P <=.001), but the biaxial flexural strength remained the same after the high-speed sintering protocol at 1590 degrees C. Grain sizes increased with increasing final sintering temperature for Zl and HT+, whereas translucency generally decreased with increasing material thickness. No monoclinic phase was detected in any group. Conclusions. The flexural strength was maintained with high-speed sintering but led to a decrease in translucency for ZD and HT+.

• Dokumententyp: Zeitschriftenartikel
• Fakultät: Medizin
• Themengebiete: 600 Technik, Medizin, angewandte Wissenschaften > 610 Medizin und Gesundheit
• ISSN: 0022-3913
• Sprache: Englisch