Fracture load and phase transformation of monolithic zirconia crowns submitted to different aging protocols
E. T. P. Bergamo, W. J. da Silva, P. F. Cesar, A. A. Del Bel Cury
ARTIGO
Inglês
Agradecimentos: The authors thank CAPES (AUX-PE-PROEX 1778/2014) for financial support; the Brazilian Synchrontron Light Laboratory, where the x-ray diffraction was performed; the Institute of Energy and Nuclear Research (IPEN), on behalf of Professor Dolores Lazar and her PhD student Anelize Arata,...
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Agradecimentos: The authors thank CAPES (AUX-PE-PROEX 1778/2014) for financial support; the Brazilian Synchrontron Light Laboratory, where the x-ray diffraction was performed; the Institute of Energy and Nuclear Research (IPEN), on behalf of Professor Dolores Lazar and her PhD student Anelize Arata, for allowing the use of Reactor Parr 4843 and for instructions on the hydrothermal test; and Laboratory Aliança for supporting the crown fabrication.
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Abstract: Monolithic zirconia crowns have many favorable properties and may potentially be used to solve dental problems such as chipping. However, monolithic zirconia crown resistance can be affected by its phase transformation when subjected to low temperatures, humidity, and stress. This study...
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Abstract: Monolithic zirconia crowns have many favorable properties and may potentially be used to solve dental problems such as chipping. However, monolithic zirconia crown resistance can be affected by its phase transformation when subjected to low temperatures, humidity, and stress. This study evaluated the fracture load and phase transformation of monolithic zirconia crowns submitted to different thermal and mechanical aging tests. Seventy monolithic zirconia crowns were randomly divided into the following five groups: control, no treatment; hydrothermal aging at 1228 degrees C, two bar for one hour; thermal fatigue, 10(4) cycles between 58 degrees C and 558 degrees C, dwell time, 30 seconds; and mechanical fatigue, 10(6) cycles with a load of 70 N, sliding of 1.5 mm at 1.4 Hz; and combination of mechanical plus thermal fatigue. Fracture load was measured with a universal testing machine. Surface changes and fracture mode and origin were examined with a scanning electron microscope. Monoclinic phase content was evaluated by x-ray diffraction. The fracture load was analyzed using one-way analysis of variance at a level of 5%, and Weibull distribution was performed. No statistically significant differences were observed in the mean fracture load and characteristic fracture load among the groups (p>0.05). The Weibull modulus ranged from 6.2 to 16.6. The failure mode was similar for all groups with the crack origin located at the contact point of the indenter. Phase transformation was shown at different surfaces of the crown in all groups (1.9% to 8.9%). In conclusion, monolithic zirconia crowns possess high fracture load, structural reliability, and low phase transformation'
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COORDENAÇÃO DE APERFEIÇOAMENTO DE PESSOAL DE NÍVEL SUPERIOR - CAPES
Fechado
Fracture load and phase transformation of monolithic zirconia crowns submitted to different aging protocols
E. T. P. Bergamo, W. J. da Silva, P. F. Cesar, A. A. Del Bel Cury
Fracture load and phase transformation of monolithic zirconia crowns submitted to different aging protocols
E. T. P. Bergamo, W. J. da Silva, P. F. Cesar, A. A. Del Bel Cury
Fontes
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Operative dentistry Vol. 5 (Sep./Oct., 2016), p. E118-E130 |