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The effect of zirconia sintering temperature on flexural strength, grain size, and contrast ratio

Stawarczyk, Bogna ; Özcan, Mutlu ; Hallmann, Lubica ; Ender, Andreas ; Mehl, Albert ; Hämmerlet, Christoph

In: Clinical Oral Investigations, 2013, vol. 17, no. 1, p. 269-274

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    Titel
    • The effect of zirconia sintering temperature on flexural strength, grain size, and contrast ratio
    Autor
    • Stawarczyk, Bogna. Clinic of Fixed and Removable Prosthodontics and Dental Material Science, Center of Dental Medicine, University of Zurich, Plattenstrasse 11, 8032, Zurich, Switzerland
    • Özcan, Mutlu. Clinic of Fixed and Removable Prosthodontics and Dental Material Science, Center of Dental Medicine, University of Zurich, Plattenstrasse 11, 8032, Zurich, Switzerland
    • Hallmann, Lubica. Clinic of Fixed and Removable Prosthodontics and Dental Material Science, Center of Dental Medicine, University of Zurich, Plattenstrasse 11, 8032, Zurich, Switzerland
    • Ender, Andreas. Clinic of Preventive Dentistry, Periodontology and Cariology, Center of Dental Medicine, University of Zurich, Plattenstrasse 11, 8032, Zurich, Switzerland
    • Mehl, Albert. Clinic of Preventive Dentistry, Periodontology and Cariology, Center of Dental Medicine, University of Zurich, Plattenstrasse 11, 8032, Zurich, Switzerland
    • Hämmerlet, Christoph. Clinic of Fixed and Removable Prosthodontics and Dental Material Science, Center of Dental Medicine, University of Zurich, Plattenstrasse 11, 8032, Zurich, Switzerland
    Dokumententyp
    • Postprint
    Sprache
    • Englisch
    Veröffentlicht in
    • Clinical Oral Investigations, 2013, vol. 17, no. 1, p. 269-274. Springer-Verlag
    Andere elektronische Ausgabe
    OAI-PMH-ID
    • oai:doc.rero.ch:318396
    Summary
    Objective: This study investigated the effect of sintering temperatures on flexural strength, contrast ratio, and grain size of zirconia. Materials and Methods: Zirconia specimens (Ceramill ZI, Amann Girrbach) were prepared in partially sintered state. Subsequently, the specimens were randomly divided into nine groups and sintered with different final sintering temperatures: 1,300°C, 1,350°C, 1,400°C, 1,450°C, 1,500°C, 1,550°C, 1,600°C, 1,650°C, or 1,700°C with 120min holding time. Three-point flexural strength (N = 198; n = 22 per group) was measured according to ISO 6872: 2008. The contrast ratio (N = 90; n = 10 per group) was measured according to ISO 2471: 2008. Grain sizes and microstructure of different groups were investigated (N = 9, n = 1 per group) with scanning electron microscope. Data were analyzed using one-way ANOVA with Scheffé test and Weibull statistics (p < 0.05). Pearson correlation coefficient was calculated between either flexural strength or contrast ratio and sintering temperatures. Results: The highest flexural strength was observed in groups sintered between 1,400°C and 1,550°C. The highest Weibull moduli were obtained for zirconia sintered at 1,400°C and the lowest at 1,700°C. The contrast ratio and the grain size were higher with the higher sintering temperature. The microstructure of the specimens sintered above 1,650°C exhibited defects. Sintering temperatures showed a significant negative correlation with both the flexural strength (r = −0.313, p < 0.001) and the contrast ratio values (r = −0.96, p < 0.001). Conclusions: The results of this study showed that the increase in sintering temperature increased the contrast ratio, but led to a negative impact on the flexural strength. Clinical Relevance: Considering the flexural strength values and Weibull moduli, the sintering temperature for the zirconia tested in this study should not exceed 1,550°C