Grain-Boundary Engineering for Aging and Slow-Crack-Growth Resistant Zirconia

• Published in: Journal of dental research Vol. 96; no. 7; pp. 774 - 779
• Main Authors: Zhang, F., Chevalier, J., Olagnon, C., Batuk, M., Hadermann, J., Van Meerbeek, B., Vleugels, J.
• Format: Journal Article
• Language: English
• Published: Los Angeles, CA SAGE Publications 01-07-2017; SAGE PUBLICATIONS, INC; SAGE Publications (UK and US)
• Subjects: Aging; Aluminum oxide; Cations; Ceramics; Ceramics - chemistry; Crack propagation; Dental Materials - chemistry; Dental Restoration, Permanent; Dental restorative materials; Dentistry; Engineering; Engineering Sciences; Grain boundaries; Hardness; Lanthanum; Materials Testing; Microscopy, Electron, Scanning; Nanotechnology; Oral cavity; Spectroscopy; Surface Properties; Time Factors; Transmission electron microscopy; Yttrium - chemistry; Zirconia; Zirconium - chemistry; nanotechnology; ceramics; restorative materials; restorative dentistry; biomaterial(s); materials science(s)
• ISSN: 0022-0345; 1544-0591
• DOI: 10.1177/0022034517698661

Ceramic materials are prone to slow crack growth, resulting in strength degradation over time. Although yttria-stabilized zirconia (Y-TZP) ceramics have higher crack resistance than other dental ceramics, their aging susceptibility threatens their long-term performance in aqueous environments such as the oral cavity. Unfortunately, increasing the aging resistance of Y-TZP ceramics normally reduces their crack resistance. Our recently conducted systematic study of doping 3Y-TZP with various trivalent cations revealed that lanthanum oxide (La2O3) and aluminum oxide (Al2O3) have the most potent effect to retard the aging kinetics of 3Y-TZP. In this study, the crack-propagation behavior of La2O3 and Al2O3 co-doped 3Y-TZP ceramics was investigated by double-torsion methods. The grain boundaries were examined using scanning transmission electron microscopy and energy-dispersive spectroscopy (STEM-EDS). Correlating these analytic data with hydrothermal aging studies using different doping systems, a strategy to strongly bind the segregated dopant cations with the oxygen vacancies at the zirconia-grain boundary was found to improve effectively the aging resistance of Y-TZP ceramics without affecting the resistance to crack propagation.