Monoclinic phase transformation and mechanical durability of zirconia ceramic after fatigue and autoclave aging

• Published in: Journal of biomedical materials research. Part B, Applied biomaterials Applied biomaterials, 2017-10, Vol.105 (7), p.1972-1977
• Main Authors: Mota, Yasmine A, Cotes, Caroline, Carvalho, Rodrigo F, Machado, João P B, Leite, Fabíola P P, Souza, Rodrigo O A, Özcan, Mutlu
• Format: Article
• Language: English
• Subjects: Aging; Aging (artificial); Alloys; Atomic force microscopy; Autoclaving; Biomedical materials; Cadmium zinc tellurides; Ceramics; Ceramics - chemistry; Cycles; Data processing; Durability; Electron microscopy; Fatigue; Flexing; Flexural strength; Hot Temperature; Materials research; Materials science; Phase transitions; Pressure; Scanning electron microscopy; Strength testing; Stress, Mechanical; Surface roughness; Tetragonal zirconia; Variance analysis; X-ray diffraction; Yttria-stabilized zirconia; Yttrium oxide; Zirconia; Zirconium - chemistry; Zirconium dioxide
• ISSN: 1552-4973; 1552-4981
• DOI: 10.1002/jbm.b.33720

This study evaluated the influence of two aging procedures on the biaxial flexural strength of yttria-stabilized tetragonal zirconia ceramics. Disc-shaped zirconia specimens and (ZE: E.max ZirCAD, Ivoclar; ZT: Zirkon Translucent, Zirkonzahn) (N = 80) (∅:12 mm; thickness:1.2 mm, ISO 6872) were prepared and randomly divided into four groups (n = 10 per group) according to the aging procedures: C: Control, no aging; M: mechanical cycling (2 × 10 cycles/3.8 Hz/200 N); AUT: Aging in autoclave at 134°C, 2 bar for 24 h; AUT + M: Autoclave aging followed by mechanical cycling. After aging, the transformed monoclinic zirconia (%) were evaluated using X-ray diffraction and surface roughness was measured using atomic force microscopy. The average grain size was measured by scanning electron microscopy and the specimens were submitted to biaxial flexural strength testing (1 mm/min, 1000 kgf in water). Data (MPa) were statistically analyzed using 2-way analysis of variance and Tukey's test (α = 0.05). Aging procedures significantly affected (p = 0.000) the flexural strength data but the effect of zirconia type was not significant (p = 0.657). AUT (936.4 ± 120.9 ) and AUT + M (867.2 ± 49.3 ) groups presented significantly higher values (p