@Article{MotaCoCaMaLeSoOz:2017:MoPhTr,
author = "Mota, Yasmine A. and Cotes, Caroline and Carvalho, Rodrigo F. and
Machado, Jo{\~a}o Paulo Barros and Leite, Fabiola P. P. and
Souza, Rodrigo O. A. and Ozcan, Mutlu",
affiliation = "{Universidade Federal de Juiz de Fora (UFJF)} and {Universidade
Estadual Paulista (UNESP)} and {Universidade Estadual Paulista
(UNESP)} and {Instituto Nacional de Pesquisas Espaciais (INPE)}
and {Universidade Federal de Juiz de Fora (UFJF)} and
{Universidade Federal do Rio Grande do Norte (UFRN)} and
{University of Z{\"u}rich}",
title = "Monoclinic phase transformation and mechanical durability of
zirconia ceramic after fatigue and autoclave aging",
journal = "Journal of Biomedical Materials Research Part B: Applied
Biomaterials",
year = "2017",
volume = "105",
number = "7",
pages = "1972--1977",
month = "Oct.",
keywords = "aging, flexural strength, mechanical cycling, phase
transformation, yttria-stabilized tetragonal zirconia.",
abstract = "ObjectivesThis study evaluated the influence of two aging
procedures on the biaxial flexural strength of yttria-stabilized
tetragonal zirconia ceramics. Material and methods. Disc-shaped
zirconia specimens and (ZE: E.max ZirCAD, Ivoclar; ZT: Zirkon
Translucent, Zirkonzahn) (N=80) (empty set :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 x 10(6) cycles/3.8 Hz/200 N); AUT:
Aging in autoclave at 134 degrees 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 (=0.05). Results. Aging procedures significantly
affected (p=0.000) the flexural strength data but the effect of
zirconia type was not significant (p=0.657). AUT(ZT) (936.4 +/-
120.9(b)) and AUT+M-ZE (867.2 +/- 49.3(b)) groups presented
significantly higher values (p<0.05) of flexural strength than
those of the control groups (C-ZT: 716.5 +/- 185.7(a); C-ZE: 779.9
+/- 114(a)) (Tukey's test). The monoclinic phase percentage (%)
was higher for AUT(ZE) (71), AUT(ZT) (66), AUT+M-ZE (71), and
AUT+M-ZM (66) compared to the C groups (ZE:0; ZT:0). Surface
roughness (mu m) was higher for AUT(ZE) (0.09), AUT(ZT) (0.08),
AUT+M-ZE (0.09 mu m), and AUT+M-ZT (0.09 mu m) than those of other
groups. Conclusions. Regardless of the zirconia type, autoclave
aging alone or with mechanical aging increased the flexure
strength but also induced higher transformation from tetragonal to
monoclinic phase in both zirconia materials tested.",
doi = "10.1002/jbm.b.33720",
url = "http://dx.doi.org/10.1002/jbm.b.33720",
issn = "1552-4973",
language = "en",
targetfile = "mota_monoclinic.pdf",
urlaccessdate = "04 maio 2024"
}