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Determination of the slow crack growth susceptibility coefficient of dental ceramics using different methods
Author(s) -
Gonzaga Carla Castiglia,
Cesar Paulo Francisco,
Miranda Walter Gomes,
Yoshimura Humberto Naoyuki
Publication year - 2011
Publication title -
journal of biomedical materials research part b: applied biomaterials
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.665
H-Index - 108
eISSN - 1552-4981
pISSN - 1552-4973
DOI - 10.1002/jbm.b.31892
Subject(s) - materials science , ceramic , composite material , indentation , fracture (geology) , dental porcelain , dental ceramics , stress (linguistics) , sign (mathematics) , fracture toughness , composite number , mathematics , cubic zirconia , mathematical analysis , linguistics , philosophy
This study compared three methods for the determination of the slow crack growth susceptibility coefficient (n) of two veneering ceramics (VM7 and d.Sign), two glass‐ceramics (Empress and Empress 2) and a glass‐infiltrated alumina composite (In‐Ceram Alumina). Discs ( n = 10) were prepared according to manufacturers' recommendations and polished. The constant stress‐rate test was performed at five constant stress rates to calculate n d . For the indentation fracture test to determine n IF , Vickers indentations were performed and the crack lengths were measured under an optical microscope. For the constant stress test (performed only for d.Sign for the determination of n s ) four constant stresses were applied and held constant until the specimens' fracture and the time to failure was recorded. All tests were performed in artificial saliva at 37°C. The n d values were 17.2 for Empress 2, followed by d.Sign (20.5), VM7 (26.5), Empress (30.2), and In‐Ceram Alumina (31.1). In‐Ceram Alumina and Empress 2 showed the highest n IF values, 66.0 and 40.2, respectively. The n IF values determined for Empress (25.2), d.Sign (25.6), and VM7 (20.1) were similar. The n s value determined for d.Sign was 31.4. It can be concluded that the n values determined for the dental ceramics evaluated were significantly influenced by the test method used. © 2011 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 2011.