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Spatial distribution of residual stresses in glass-ZrO2 sphero-cylindrical bilayers.
Wendler, Michael; Belli, Renan; Petschelt, Anselm; Lohbauer, Ulrich.
Afiliación
  • Wendler M; Friedrich-Alexander Universität Erlangen-Nürnberg (FAU), Dental Clinic 1-Operative Dentistry and Periodontology, Research Laboratory for Dental Biomaterials, Glueckstrasse 11, 91054 Erlangen, Germany; Department of Restorative Dentistry, Faculty of Dentistry, University of Concepción, Concepción, Ch
  • Belli R; Friedrich-Alexander Universität Erlangen-Nürnberg (FAU), Dental Clinic 1-Operative Dentistry and Periodontology, Research Laboratory for Dental Biomaterials, Glueckstrasse 11, 91054 Erlangen, Germany.
  • Petschelt A; Friedrich-Alexander Universität Erlangen-Nürnberg (FAU), Dental Clinic 1-Operative Dentistry and Periodontology, Research Laboratory for Dental Biomaterials, Glueckstrasse 11, 91054 Erlangen, Germany.
  • Lohbauer U; Friedrich-Alexander Universität Erlangen-Nürnberg (FAU), Dental Clinic 1-Operative Dentistry and Periodontology, Research Laboratory for Dental Biomaterials, Glueckstrasse 11, 91054 Erlangen, Germany. Electronic address: ulrich.lohbauer@fau.de.
J Mech Behav Biomed Mater ; 60: 535-546, 2016 07.
Article en En | MEDLINE | ID: mdl-27043169
ABSTRACT
Residual stresses arising from inhomogeneous cooling after sintering have shown to play a preponderant role in the higher incidence of chippings observed for glass-zirconia dental prostheses. Still, current descriptions of their nature and distribution have failed to reconcile with clinical findings. Therefore, an axisymmetric sphero-cylindrical bilayer model was used in this study to determine the effect of the cooling rate on the final spatial distribution of residual stresses. Zirconia frameworks with two different radii (1.6 and 3.2mm) were CAD/CAM fabricated. Subsequent glass overlays with two different thickness ratios (11 and 21) were generated and heat pressed onto the zirconia substrates. The obtained structures were submitted to a last firing process and fast- (45°C/s) or slow-cooled (0.5°C/s) to room temperature. Unbonded bilayers were produced by firing glass overlays onto boron nitride coated zirconia. Thin sagittal and transversal sections were obtained from the specimens to assess residual stress distribution by means of light birefringence. The applied cooling rates did not affect distribution or magnitude of radial residual stresses (sagittal sections), whereas increased hoop stress magnitudes were measured (transversal sections) in fast-cooled specimens. A distinct stress nature was observed for the hoop stress component of unbonded overlays after fast cooling. Interaction between stress components seems to govern the final stress distribution, highlighting the importance of a multiaxial assessment of this problem in three-dimensional structures.
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Texto completo: 1 Colección: 01-internacional Base de datos: MEDLINE Asunto principal: Circonio / Coronas con Frente Estético / Vidrio Tipo de estudio: Prognostic_studies Idioma: En Revista: J Mech Behav Biomed Mater Asunto de la revista: ENGENHARIA BIOMEDICA Año: 2016 Tipo del documento: Article País de afiliación: Suiza

Texto completo: 1 Colección: 01-internacional Base de datos: MEDLINE Asunto principal: Circonio / Coronas con Frente Estético / Vidrio Tipo de estudio: Prognostic_studies Idioma: En Revista: J Mech Behav Biomed Mater Asunto de la revista: ENGENHARIA BIOMEDICA Año: 2016 Tipo del documento: Article País de afiliación: Suiza