Residual micro-stress distributions in heat-pressed ceramic on zirconia and porcelain-fused to metal systems: Analysis by FIB–DIC ring-core method and correlation with fracture toughness.
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| Title: | Residual micro-stress distributions in heat-pressed ceramic on zirconia and porcelain-fused to metal systems: Analysis by FIB–DIC ring-core method and correlation with fracture toughness. |
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| Authors: | Sebastiani, M.1 marco.sebastiani@stm.uniroma3.it, Massimi, F.1, Merlati, G.2, Bemporad, E.1 |
| Source: | Dental Materials. Nov2015, Vol. 31 Issue 11, p1396-1405. 10p. |
| Subjects: | Dental ceramic metals, Zirconium oxide, Porcelain, Fracture toughness, Strains & stresses (Mechanics) |
| Abstract: | Objectives The production of fixed partial dentures (FPDs) induces complex residual stress profiles, due to both the thermal expansion coefficient mismatch between the veneering ceramic and the framework and to the thermal gradients occurring during the final cooling. Detailed knowledge of residual stress distributions in the veneering ceramics is important to understand the interface phenomena with the framework and the consequences of the different firing systems. The first objective of this study was to analyse the residual stress distribution in heat-pressed ceramic on zirconia core with micrometer spatial resolution, with also a focus on the stress at the interface versus porcelain-fused-to-metal samples. The second purpose was to correlate the residual stress with the fracture toughness. Methods The micron-scale focused ion beam (FIB) ring-core method was used to map the residual stress over the cross-sections of the veneering ceramics. The methodology is based on FIB micro-milling of annular trenches, combined with high-resolution in situ scanning electron microscope (SEM) imaging, a full field strain analysis by digital image correlation (DIC) and numerical models for residual stress calculation. Fracture toughness was evaluated by using high load Vickers indentation and hardness/modulus were measured by nanoindentation testing also across the interfaces. Results Both prosthetic systems showed a compressive stress at the ceramic surface on a micron-scale. The stress profile for porcelain fused to metal (PFM) showed a transition to tensile stress at the half of the layer, whilst the stress in proximity of the interface was more compressive in both the cases. Residual stress on a micron scale are higher in magnitude than the corresponding macro-scale values reported in the literature, due to the stress relaxation given, at larger scales, by micro-voids and cracks. The stress field was directly correlated with the indentation fracture toughness, which was higher in those areas where the compressive stress is greater. Stress analysis in correspondence of interfacial porosity for the zirconia sample also showed that micro-defects could induce local modifications of the residual stress field, which may even locally generate a tensile stress state. Significance The interfacial stress in dental systems was analysed on a micron scale and can give further insights into the process/property/performance correlation for this class of materials. In particular, interfacial and/or local modifications of the residual stress are expected to have a significant influence on crack nucleation mechanism in correspondence of micro-defects. A direct correlation between residual stress distribution and fracture toughness was proposed. It is noteworthy that the method can be used to study real crowns and bridges. In fact, complex geometries can be easily analysed by this procedure. [ABSTRACT FROM AUTHOR] |
| Copyright of Dental Materials is the property of Elsevier B.V. and its content may not be copied or emailed to multiple sites without the copyright holder's express written permission. Additionally, content may not be used with any artificial intelligence tools or machine learning technologies. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.) | |
| Database: | Engineering Source |
| FullText | Text: Availability: 0 |
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| Header | DbId: egs DbLabel: Engineering Source An: 110386284 AccessLevel: 6 PubType: Academic Journal PubTypeId: academicJournal PreciseRelevancyScore: 0 |
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| Items | – Name: Title Label: Title Group: Ti Data: Residual micro-stress distributions in heat-pressed ceramic on zirconia and porcelain-fused to metal systems: Analysis by FIB–DIC ring-core method and correlation with fracture toughness. – Name: Author Label: Authors Group: Au Data: <searchLink fieldCode="AR" term="%22Sebastiani%2C+M%2E%22">Sebastiani, M.</searchLink><relatesTo>1</relatesTo><i> marco.sebastiani@stm.uniroma3.it</i><br /><searchLink fieldCode="AR" term="%22Massimi%2C+F%2E%22">Massimi, F.</searchLink><relatesTo>1</relatesTo><br /><searchLink fieldCode="AR" term="%22Merlati%2C+G%2E%22">Merlati, G.</searchLink><relatesTo>2</relatesTo><br /><searchLink fieldCode="AR" term="%22Bemporad%2C+E%2E%22">Bemporad, E.</searchLink><relatesTo>1</relatesTo> – Name: TitleSource Label: Source Group: Src Data: <searchLink fieldCode="JN" term="%22Dental+Materials%22">Dental Materials</searchLink>. Nov2015, Vol. 31 Issue 11, p1396-1405. 10p. – Name: Subject Label: Subjects Group: Su Data: <searchLink fieldCode="DE" term="%22Dental+ceramic+metals%22">Dental ceramic metals</searchLink><br /><searchLink fieldCode="DE" term="%22Zirconium+oxide%22">Zirconium oxide</searchLink><br /><searchLink fieldCode="DE" term="%22Porcelain%22">Porcelain</searchLink><br /><searchLink fieldCode="DE" term="%22Fracture+toughness%22">Fracture toughness</searchLink><br /><searchLink fieldCode="DE" term="%22Strains+%26+stresses+%28Mechanics%29%22">Strains & stresses (Mechanics)</searchLink> – Name: Abstract Label: Abstract Group: Ab Data: Objectives The production of fixed partial dentures (FPDs) induces complex residual stress profiles, due to both the thermal expansion coefficient mismatch between the veneering ceramic and the framework and to the thermal gradients occurring during the final cooling. Detailed knowledge of residual stress distributions in the veneering ceramics is important to understand the interface phenomena with the framework and the consequences of the different firing systems. The first objective of this study was to analyse the residual stress distribution in heat-pressed ceramic on zirconia core with micrometer spatial resolution, with also a focus on the stress at the interface versus porcelain-fused-to-metal samples. The second purpose was to correlate the residual stress with the fracture toughness. Methods The micron-scale focused ion beam (FIB) ring-core method was used to map the residual stress over the cross-sections of the veneering ceramics. The methodology is based on FIB micro-milling of annular trenches, combined with high-resolution in situ scanning electron microscope (SEM) imaging, a full field strain analysis by digital image correlation (DIC) and numerical models for residual stress calculation. Fracture toughness was evaluated by using high load Vickers indentation and hardness/modulus were measured by nanoindentation testing also across the interfaces. Results Both prosthetic systems showed a compressive stress at the ceramic surface on a micron-scale. The stress profile for porcelain fused to metal (PFM) showed a transition to tensile stress at the half of the layer, whilst the stress in proximity of the interface was more compressive in both the cases. Residual stress on a micron scale are higher in magnitude than the corresponding macro-scale values reported in the literature, due to the stress relaxation given, at larger scales, by micro-voids and cracks. The stress field was directly correlated with the indentation fracture toughness, which was higher in those areas where the compressive stress is greater. Stress analysis in correspondence of interfacial porosity for the zirconia sample also showed that micro-defects could induce local modifications of the residual stress field, which may even locally generate a tensile stress state. Significance The interfacial stress in dental systems was analysed on a micron scale and can give further insights into the process/property/performance correlation for this class of materials. In particular, interfacial and/or local modifications of the residual stress are expected to have a significant influence on crack nucleation mechanism in correspondence of micro-defects. A direct correlation between residual stress distribution and fracture toughness was proposed. It is noteworthy that the method can be used to study real crowns and bridges. In fact, complex geometries can be easily analysed by this procedure. [ABSTRACT FROM AUTHOR] – Name: AbstractSuppliedCopyright Label: Group: Ab Data: <i>Copyright of Dental Materials is the property of Elsevier B.V. and its content may not be copied or emailed to multiple sites without the copyright holder's express written permission. Additionally, content may not be used with any artificial intelligence tools or machine learning technologies. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract.</i> (Copyright applies to all Abstracts.) |
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| RecordInfo | BibRecord: BibEntity: Identifiers: – Type: doi Value: 10.1016/j.dental.2015.08.158 Languages: – Code: eng Text: English PhysicalDescription: Pagination: PageCount: 10 StartPage: 1396 Subjects: – SubjectFull: Dental ceramic metals Type: general – SubjectFull: Zirconium oxide Type: general – SubjectFull: Porcelain Type: general – SubjectFull: Fracture toughness Type: general – SubjectFull: Strains & stresses (Mechanics) Type: general Titles: – TitleFull: Residual micro-stress distributions in heat-pressed ceramic on zirconia and porcelain-fused to metal systems: Analysis by FIB–DIC ring-core method and correlation with fracture toughness. Type: main BibRelationships: HasContributorRelationships: – PersonEntity: Name: NameFull: Sebastiani, M. – PersonEntity: Name: NameFull: Massimi, F. – PersonEntity: Name: NameFull: Merlati, G. – PersonEntity: Name: NameFull: Bemporad, E. IsPartOfRelationships: – BibEntity: Dates: – D: 01 M: 11 Text: Nov2015 Type: published Y: 2015 Identifiers: – Type: issn-print Value: 01095641 Numbering: – Type: volume Value: 31 – Type: issue Value: 11 Titles: – TitleFull: Dental Materials Type: main |
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