Effect of autoclave induced low-temperature degradation on the adhesion energy between yttria-stabilized zirconia veneered with porcelain
Autor: | Liz Girvan, Stephanie Ting, J. Neil Waddell, Kai Chun Li, Ludwig Jansen van Vuuren, David J. Prior, Michael V. Swain |
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Rok vydání: | 2013 |
Předmět: |
Strain energy release rate
Materials science Bond strength Scanning electron microscope Temperature Spectrometry X-Ray Emission Adhesion Dental Porcelain Autoclave Dental Veneers X-Ray Diffraction Mechanics of Materials Materials Testing Microscopy Electron Scanning Yttrium General Materials Science Cubic zirconia Zirconium Composite material General Dentistry Yttria-stabilized zirconia Electron backscatter diffraction |
Zdroj: | Dental Materials. 29:e263-e270 |
ISSN: | 0109-5641 |
Popis: | To investigate the effect of autoclave induced low-temperature degradation on the adhesion energy between yttria-stabilized zirconia veneered with porcelain.The strain energy release rate using a four-point bending stable fracture test was evaluated for two different porcelains [leucite containing (VM9) and glass (Zirox) porcelain] veneered to zirconia. Prior to veneering the zirconia had been subjected to 0 (control), 1, 5, 10 and 20 autoclave cycles. The specimens were manufactured to a total bi-layer dimension of 30 mm × 8 mm × 3 mm. Subsequent scanning electron microscopy/energy dispersive spectrometry, electron backscatter diffraction and X-ray diffraction analysis were performed to identify the phase transformation and fracture behavior.The strain energy release rate for debonding of the VM9 specimens were significantly higher (p0.05) compared to the Zirox specimens across all test groups. Increasing autoclave cycles lowered the strain energy release rate significantly (p0.05) from 18.67 J/m(2) (control) to the lowest of 12.79 J/m(2) (cycle 10) for only the VM9 specimens. SEM analyses showed predominant cohesive fracture within the porcelain for all cycle groups. XRD analysis of the substrate prior to veneering confirmed a tetragonal to monoclinic phase transformation with increasing the number of autoclave cycles between 5 and 20. The monoclinic phase reverted back to tetragonal phase after undergoing conventional porcelain firing cycles. EBSD data showed significant changes of the grain size distribution between the control and autoclaved specimen (cycle 20).Increasing autoclave cycles only significantly decreased the adhesion of the VM9 layered specimens. In addition, a conventional porcelain firing schedule completely reverted the monoclinic phase back to tetragonal. |
Databáze: | OpenAIRE |
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