Effect of thermal expansion mismatch on the Y-TZP/veneer interfacial adhesion determined by strain energy release rate

Abstract

Thermal residual stresses and strain energy release rates were correlated. Slight compressive stresses in the region of -20MPa were beneficial for the Y-TZP/veneer interfacial adhesion. Stresses higher or lower than this value exhibited decreased adhesion.

Efecto del liner en la resistencia adhesiva de cerámica feldespática a la zirconia utilizando protocolo de enfriamiento lento

“…24,25 Algunos autores sugieren que una tensión residual excesiva en la cerámica de recubrimiento sometida a cargas oclusales podría ser uno de los factores que propician la aparición de chipping o delaminación de la cerámica de recubrimiento con estructuras a base de zirconia. 7,21,26 Se ha descrito una relación entre la utilización de protocolos de enfriamiento lento y disminución de la fuerza adhesiva de la cerámica de recubrimiento a la zirconia, 20 este hallazgo probablemente sea una explicación a los resultados obtenidos en esta investigación, donde la resistencia adhesiva máxima es de 16,36 MPa. Estos resultados son menores al compararlos con resultados de estudios que se realizaron sin la utilización de protocolos de enfriamiento lento y promediaron resistencia adhesiva de 20 hasta 35 Mpa.…”

Interfacial adhesion of zirconia/veneer bilayers with different thermal characteristics

“…This may be important, as stress distribution at a bilayer interface is significantly affected by the layer thickness of the components 13,29) . Recently, strain energy release rate has been evaluated with zirconia core and veneer ceramics and has been found to be a reliable method for analysing interfacial adhesion 14,15) . These studies revealed that interfacial adhesion between the materials is significantly influenced by residual stresses, which are themselves affected by the thermal characteristics of the components.…”

“…These studies revealed that interfacial adhesion between the materials is significantly influenced by residual stresses, which are themselves affected by the thermal characteristics of the components. In this context, slight compressive stresses of about −20 MPa (correlating to a CTE mismatch of ≈1.4 ppm K −1 ) in the adhesion zone have been reported to be beneficial for zirconia/veneer interfacial adhesion 14) . Beside the thermal characteristics of these materials, these stresses could also be influenced by modulating the cooling rate within the firing process 15) .…”

“…Beside the CTE mismatch of the bilayer components, these variations in the The crack started at the pre-notch, bifurcated near the core/veneer interface and propagated within the adhesive interface of the components. chemical composition of the veneer ceramics may have significantly affected interfacial adhesion 14,16) . Therefore, in the present study, veneer ceramics with different thermal characteristics but almost identical chemical compositions and mechanical characteristics and from only one manufacturer were evaluated.…”

“…These stresses are governed by the mismatch between the coefficients of thermal expansion (CTE) of the core and the veneer, the cooling rate after the sintering process, viscoelastic effects in the range of the glass transition temperature and the composition of the core and veneer ceramics 13) . Göstemeyer et al confirmed some of these theoretical aspects in an in-vitro study, by evaluating the influence of CTE and cooling rate, using a sensitive measurement method (strain energy release rate) 14,15) . Fischer et al reported similar results with conventional bond strength tests 10,11) .…”