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Strength and Weibull parameters of one feldsphatic ceramic veneer to zirconia core submitted to different cooling rates

Grant number: 09/17737-0
Support type:Scholarships in Brazil - Scientific Initiation
Effective date (Start): March 01, 2010
Effective date (End): December 31, 2011
Field of knowledge:Health Sciences - Dentistry - Dental Materials
Principal researcher:Gelson Luis Adabo
Grantee:Diogo Longhini
Home Institution: Faculdade de Odontologia (FOAr). Universidade Estadual Paulista (UNESP). Campus de Araraquara. Araraquara , SP, Brazil

Abstract

Recently, yttrium oxide-stabilized tetragonal zirconia polycrystalline (3Y-TZP) have been introduced in prosthetic dentistry to be used as all-ceramic fixed prostheses core. Despite its good mechanical properties, during sintering of venner ceramic, an inadequate cooling rate or a thermal mismatch between venner ceramic and 3Y-TZP can cause problems such as chipping and fracture of venner ceramic. During cooling, below glass transition temperature (Tg), ceramic changes from plastic to solid state, which does not allow the release of generated tension. Thus, it is important that veneer ceramic has sufficient mechanical strength to withstand such tensions and also has suitable structural reliability to be used in all-ceramic system. It is suggested that an inadequate cooling rate can increase the residual stress and it can be a possible cause of failure in theses prostheses. The purpose of this project is to evaluate the flexural strength, the Weibull parameters and the fractography of monolayer (only veneer) specimens under different cooling rates. (AU)