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The bending stress distribution in bilayered and graded zirconia-based dental ceramics
- Source :
- Ceramics International. 42:11025-11031
- Publication Year :
- 2016
- Publisher :
- Elsevier BV, 2016.
-
Abstract
- The purpose of this study was to evaluate the biaxial flexural stresses in classic bilayered and in graded zirconia-feldspathic porcelain composites. A finite element method and an analytical model were used to simulate the piston-on-ring test and to predict the biaxial stress distributions across the thickness of the bilayer and graded zirconia-feldspathic porcelain discs. An axisymmetric model and a flexure formula of Hsueh et al. were used in the FEM and analytical analysis, respectively. Four porcelain thicknesses were tested in the bilayered discs. In graded discs, continuous and stepwise transitions from the bottom zirconia layer to the top porcelain layer were studied. The resulting stresses across the thickness, measured along the central axis of the disc, for the bilayered and graded discs were compared. In bilayered discs, the maximum tensile stress decreased while the stress mismatch (at the interface) increased with the porcelain layer thickness. The optimized balance between both variables is achieved for a porcelain thickness ratio in the range of 0.30–0.35. In graded discs, the highest tensile stresses were registered for porcelain rich interlayers (p=0.25) whereas the zirconia rich ones (p=8) yield the lowest tensile stresses. In addition, the maximum stresses in a graded structure can be tailored by altering compositional gradients. A decrease in maximum stresses with increasing values of p (a scaling exponent in the power law function) was observed. Our findings showed a good agreement between the analytical and simulated models, particularly in the tensile region of the disc. Graded zirconia-feldspathic porcelain composites exhibited a more favourable stress distribution relative to conventional bilayered systems. This fact can significantly impact the clinical performance of zirconia-feldspathic porcelain prostheses, namely reducing the fracture incidence of zirconia and the chipping and delamination of porcelain.
- Subjects :
- Yield (engineering)
Materials science
Process Chemistry and Technology
Delamination
Biaxial tensile test
030206 dentistry
02 engineering and technology
021001 nanoscience & nanotechnology
Article
Surfaces, Coatings and Films
Electronic, Optical and Magnetic Materials
Stress (mechanics)
03 medical and health sciences
0302 clinical medicine
Flexural strength
Ultimate tensile strength
Materials Chemistry
Ceramics and Composites
Fracture (geology)
Cubic zirconia
Composite material
0210 nano-technology
Subjects
Details
- ISSN :
- 02728842
- Volume :
- 42
- Database :
- OpenAIRE
- Journal :
- Ceramics International
- Accession number :
- edsair.doi.dedup.....715bdc7e2fee3bb94819178051a18c5f