Alumina‐toughened zirconia for dental applications: Physicochemical, mechanical, optical, and residual stress characterization after artificial aging

• Published in: Journal of biomedical materials research. Part B, Applied biomaterials Vol. 109; no. 8; pp. 1135 - 1144
• Main Authors: Bergamo, Edmara T. P., Cardoso, Karina B., Lino, Lucas F. O., Campos, Tiago M. B., Monteiro, Kelli N., Cesar, Paulo F., Genova, Luis A., Thim, Gilmar P., Coelho, Paulo G., Bonfante, Estevam A.
• Format: Journal Article
• Language: English
• Published: Hoboken, USA John Wiley & Sons, Inc 01.08.2021; Wiley Subscription Services, Inc
• Subjects: Aging; Aging (artificial); Aluminum oxide; Aluminum Oxide - chemistry; Biomedical materials; ceramic composite; ceramics; Compressive properties; Crystal structure; Crystallinity; Dental materials; Dental Materials - chemistry; Flexural strength; Grain size; Isostatic pressing; Materials research; Materials science; Materials Testing; Mechanical properties; Opacity; Optical properties; Polycrystals; Pressure; Residual stress; Scanning electron microscopy; Sintering (powder metallurgy); Tetragonal zirconia; Tetragonal zirconia polycrystals; Time Factors; X-ray diffraction; Yttrium oxide; Zirconia; Zirconium - chemistry; Zirconium dioxide; ceramics; optical properties; zirconia; aging; ceramic composite; mechanical properties
• ISSN: 1552-4973; 1552-4981
• DOI: 10.1002/jbm.b.34776

To characterize the physicomechanical properties of an alumina‐toughened zirconia (ATZ). ATZ synthesis consisted of the addition of alumina particles in an yttria‐stabilized tetragonal zirconia polycrystals (3Y‐TZP) matrix. Specimens were obtained by uniaxial and isostatic pressing ATZ and 3Y‐TZP powders and sintering at 1600°C/1 h and 1550°C/1 h, respectively. Crystalline content and residual stress were evaluated using X‐ray diffraction (XRD). Microstructure was characterized by scanning electron microscopy (SEM). Optical properties were determined by reflectance test. Mechanical properties were assessed by biaxial flexural strength test. All analyses were performed before and after aging (134°C, 20 h, 2 bar). XRD and SEM revealed a typical ATZ and 3Y‐TZP crystalline content, chiefly tetragonal phase, with a dense polycrystalline matrix, though a smaller grain size for ATZ. Aging triggered a similar monoclinic transformation for both systems; however, ATZ exhibited higher residual compressive stresses than 3Y‐TZP. While as‐processed 3Y‐TZP demonstrated significantly higher characteristic strength relative to ATZ, no significant difference was observed after aging (~215 MPa increase in the ATZ strength). ATZ presented significantly higher opacity relative to 3Y‐TZP, although aging significantly increased the translucency of both systems (increase difference significantly higher in the 3Y‐TZP compared to ATZ). ATZ physicomechanical properties support its applicability in the dental field, with a lower detrimental effect of aging relative to 3Y‐TZP.