Mechanical properties of monolithic and bilayered lithium disilicate ceramics in comparison to zirconia-based all-ceramics
Date
2013
DOI
Authors
Eshky, Ammar Ali
Version
OA Version
Citation
Abstract
Objectives: Evaluate the mechanical properties of monolithic and bilayered lithium disilicate and zirconia based all-ceramics.
Materials and methods: Monolithic and bilayered disc-shape specimens of lithium disilicate and zirconium oxide were prepared and subjected to different mechanical testing. In the first test, three groups containing 10 disc-shape specimens of pressable lithium disilicate ceramic (IPS e.max Press, Ivoclar vivadent) were prepared with different surface finishing including no treatment, polishing or grinding. Ball on three-ball bend test was conducted on all groups to evaluate the effect of surface treatment on the biaxial flexural strength of e.max Press. Also, surface roughness measurements (Ra) of each group were evaluated to verify the correlation between the surface roughness and the biaxial flexural strength of e.max press. ln the second test, four groups containing monolithic disc-shape specimens were prepared and tested for biaxialflexural strength, as follows: 1) Pressable lithium disilicate ceramic (IPS e.max Press, Ivoclar vivadent). 2) CAD-CAM lithium disilicate ceramic (IPS e.max CAD, Ivoclar vivadent). 3) Veneering low-fusing nano-fluorapatite glass-ceramic (IPS e.max Ceram, Ivoclar vivadent). 4) Zirconium oxide ceramic (VITA ln-Ceram YZ, Vident). In the third test, six groups containing monolithic or bilayered specimens were prepared and loaded to failure, as follows: 1) Monolithic discs of pressable lithium disilicate ceramic (IPS e.max Press). 2) Monolithic discs of CAD-CAM lithium disilicate ceramic (IPS e.max CAD). 3) Bilayered discs of lithium disilicate subjected to tension (IPS e.max Press) layered with veneering ceramic (IPS e.max Ceram) subjected to compression. 4) Bilayered discs of lithium disilicate subjected to compression (IPS e.max Press) layered with veneering ceramic (IPS e.max Ceram) subjected to tension. 5) Bilayered discs of zirconium oxide (VIT A In-Ceram YZ) subjected to tension layered with veneering ceramic (IPS e.max Ceram) subjected to compression. 6) Bilayered discs of zirconium oxide (VITA In-Ceram YZ) subjected to compression layered with veneering ceramic (IPS e.max Ceram) subjected to tension. In the last test, two groups containing bilayered specimens were prepared and tested for shear strength, as follows:1) Cylinder-shape layering ceramic (IPS e.max Ceram) bonded to a disc-shape lithium disilicate substrate (IPS e.max Press). 2) Cylinder-shape layering ceramic (IPS e.max Ceram) bonded to a disc-Shape zirconium oxide substrate (VITA In-Ceram YZ).
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Thesis/Dissertation (DScD) --Boston University, Henry M. Goldman School of Dental Medicine, 2013 (Department of Biomaterials).
Includes bibliographic references: leaves 114-119.
Thesis/Dissertation (DScD) --Boston University, Henry M. Goldman School of Dental Medicine, 2013 (Department of Biomaterials).
Includes bibliographic references: leaves 114-119.
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This work is protected by copyright. Downloading is restricted to the BU community. If you are the author of this work and would like to make it publicly available, please contact open-help@bu.edu.