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Influence of grain size and veneer firing process on the flexural strength of zirconia ceramics
Author(s) -
Nakamura Keisuke,
Adolfsson Erik,
Milleding Percy,
Kanno Taro,
Örtengren Ulf
Publication year - 2012
Publication title -
european journal of oral sciences
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.802
H-Index - 93
eISSN - 1600-0722
pISSN - 0909-8836
DOI - 10.1111/j.1600-0722.2012.00958.x
Subject(s) - flexural strength , veneer , cubic zirconia , materials science , grain size , ceramic , composite material , scanning electron microscope , sintering , yttria stabilized zirconia
Nakamura K, Adolfsson E, Milleding P, Kanno T, Örtengren U. Influence of grain size and veneer firing process on the flexural strength of zirconia ceramics.
Eur J Oral Sci 2012; 120: 249–254. © 2012 Eur J Oral Sci The aim of the present investigation was to study the influence of grain size on the strength of yttria‐stabilized zirconia upon exposure to an additional heat treatment, mimicking the veneering process. The green bodies of zirconia discs prepared by cold isostatic pressing were sintered at 1,425, 1,500, or 1,575°C to customize the grain size. The disc‐shaped specimens were highly polished and then processed with or without additional heat treatments (five times at 850–930°C). Ten specimens from each treatment group were subjected to a biaxial flexural strength test according to the ISO 6872 standard. The grain size of the specimens was analyzed by the mean linear intercept technique using scanning electron microscopy. It was demonstrated that the mechanical strength of zirconia ceramics was not reduced by the veneer firing processes when polished specimens were used, but the strength was found to decrease with increasing grain size. The raw materials and the sintering process used should be selected appropriately to avoid grain coarsening because it was found that the strength was influenced by large grains.