Effect of different cooling rates on a feldspathic ceramic veneer for zirconia core

• Grant number: 09/17735-8
• Support type: Scholarships in Brazil - Doctorate
• Effective date (Start): April 01, 2010
• Effective date (End): November 30, 2012
• Field of knowledge: Health Sciences - Dentistry - Dental Materials
• Principal researcher: Gelson Luis Adabo
• Grantee: Antonio Alves de Almeida Junior
• Home Institution: Faculdade de Odontologia (FOAr). Universidade Estadual Paulista (UNESP). Campus de Araraquara. Araraquara , SP, Brazil

Abstract

Denses ceramics based on yttrium oxide-stabilized tetragonal zirconia polycrystalline (3Y-TZP) have been recently introduced in prosthetic dentistry causing a great interest due their properties. Zirconia based materials are restricted to indirect core restorations because they do not have dental aesthetic which can be achieved by successive firings of veneer feldspathic ceramic. However, complications such as chipping and fracture of venner ceramic raise the failure rate in about 15% in five years. Factors that may cause these complications include excessive thermal residual stress generated during cooling and caused by the difference in thermal expansion coefficient (TEC) between zirconia and venner ceramic. This residual stress occurs during sintering and can be caused by a mismatch of the TEC between both materials or by an inadequate cooling rate when the ceramic changes from plastic to solid state (glass transition temperature - Tg). Therefore, the purpose of this project is to evaluate the flexural strength, Weibull parameters, fractography analysis, Vickers hardness and fracture toughness, and to perform differential thermal analysis and X-ray diffraction of monolayer (only veneer) and bilayer (veneer and zirconia core) specimens under different cooling rates. Moreover, it is important to simulate the sintering of ceramic venner onto zirconia core with 3D finite element analyses to understand the influence of different cooling conditions on the clinical failure of chipping the interface zirconia core/ceramic veneer and predict the residual stresses areas. (AU)

Scientific publications

(References retrieved automatically from Web of Science and SciELO through information on FAPESP grants and their corresponding numbers as mentioned in the publications by the authors)

DE ALMEIDA JUNIOR, ANTONIO ALVES; LONGHINI, DIOGO; SUZUKI, PAULO ATSUSHI; RIBEIRO, SEBASTIAO; SANTOS, CLAUDINEI; ADABO, GELSON LUIS. Effect of the Cooling Rate on the Properties of Veneer Porcelain for Zirconia Dental Prosthesis. MATERIALS RESEARCH-IBERO-AMERICAN JOURNAL OF MATERIALS, v. 20, n. 5, p. 1418-1424, SEP-OCT 2017. (10/05469-9, 09/17735-8)

ANTONIO ALVES DE ALMEIDA-JÚNIOR; DIOGO LONGHINI; BEATRIZ REGALADO GALVÃO; CLAUDINEI DOS SANTOS; GELSON LUIS ADABO. Strength of 3Y-TZP and feldspathic porcelain subjected to different cooling methods. Braz. J. Oral Sci., v. 13, n. 2, p. 124-128, 2014-06-00. (09/17735-8, 10/05469-9)