The effects of viscoelastic parameters on residual stress development in a zirconia/glass bilayer dental ceramic
| Autor: | Burak Taskonak, Jiahau Yan, John J. Mecholsky, Gilberto Antonio Borges, Kenneth J. Anusavice, B. Keith Moore |
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| Rok vydání: | 2008 |
| Předmět: |
Ceramics
Hot Temperature Time Factors Materials science Surface Properties medicine.medical_treatment Mineralogy Bending Mechanics Dental Materials X-Ray Diffraction Flexural strength Residual stress Materials Testing medicine Humans Transition Temperature Yttrium General Materials Science Ceramic Composite material Pliability General Dentistry Crystallography Viscosity Bilayer Fracture mechanics Elasticity Mechanics of Materials visual_art visual_art.visual_art_medium Veneer Glass Stress Mechanical Zirconium Glass transition Algorithms |
| Zdroj: | Dental Materials. 24:1149-1155 |
| ISSN: | 0109-5641 |
| DOI: | 10.1016/j.dental.2008.01.004 |
| Popis: | Objectives The aim of this study was to test the hypothesis that the residual stresses in a zirconia-based bilayer dental composite system can be tailored through heat treatment above and below the glass transition temperature of glass veneers. Methods Ceramic bilayer disc specimens were prepared from a zirconia core and a glass veneer. Each bilayer ceramic group was heat treated 40 °C below, 20 °C and 40 °C above and at the glass transition temperature of the glass veneer, and cooled using a fast or a slow cooling rate. Specimens were tested for flexure strength using a biaxial bending fixture. Residual stresses were calculated using a fracture mechanics approach. Results Heat treatments produced significant differences ( p ≤ 0.05) between the mean flexural strengths of the heat treatment groups when the specimens were cooled using a fast cooling rate. However, there was not a significant difference ( p > 0.05) between the mean flexural strengths of the heat treatment groups when a slow cooling rate was used. Fractures initiated from the veneer surfaces of the specimens. Significance Heat treatment above and below the glass transition temperature of the veneer layer, and the cooling rate have a significant effect on the flexural strength of the bilayer ceramic laminates. The existence of residual compressive stress is the most likely reason for the observed strength increases. Residual stresses can be modified using the elastic-viscoelastic relaxation behavior of a glass veneer. |
| Databáze: | OpenAIRE |
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