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Investigations into the interface failure of yttria partially stabilised zirconia - porcelain dental prostheses through microscale residual stress and phase quantification

DOI: 10.1016/j.dental.2019.08.098 DOI Help

Authors: Alexander Lunt (University of Oxford) , Enrico Salvati (University of Oxford) , Nikolaos Baimpas (University of Oxford) , Igor Dolbnya (Diamond Light Source) , Tee Khin Neo (Specialist Dental Group, Mount Elizabeth Orchard) , Alexander Korsunsky (University of Oxford)
Co-authored by industrial partner: No

Type: Journal Paper
Journal: Dental Materials

State: Published (Approved)
Published: September 2019
Diamond Proposal Number(s): 8823

Abstract: Objectives: Yttria Partially Stabilised Zirconia (YPSZ) is a high strength ceramic which has become widely used in porcelain veneered dental copings due to its exceptional toughness. Within these components the residual stress and crystallographic phase of YPSZ close to the interface are highly influential in the primary failure mode; near interface porcelain chipping. In order to improve present understanding of this behaviour, characterisation of these parameters is needed at an improved spatial resolution. Methods: In this study transmission micro-focus X-ray Diffraction, Raman spectroscopy, and focused ion beam milling residual stress analysis techniques have, for the first time, been used to quantify and cross-validate the microscale spatial variation of phase and residual stress of YPSZ in a prosthesis cross-section. Results: The results of all techniques were found to be comparable and complementary. Monoclinic YPSZ was observed within the first 10 μm of the YPSZ-porcelain interface with a maximum volume fraction of 60%. Tensile stresses were observed within the first 150μm of the interface with a maximum value of ≈300MPa at 50μm from the interface. The remainder of the coping was in mild compression at ≈ − 30 MPa, with shear stresses of a similar magnitude also being induced by the YPSZ phase transformation. Significance: The analysis indicates that the interaction between phase transformation, residual stress and porcelain creep at YPSZ-porcelain interface results in a localised porcelain fracture toughness reduction. This explains the increased propensity of failure at this location, and can be used as a basis for improving prosthesis design.

Journal Keywords: Micro-focus X-ray diffraction; Raman spectroscopy; Yttria partially stabilised zirconia- porcelain dental prostheses; Residual stress analysis; Phase mapping

Subject Areas: Materials


Instruments: B16-Test Beamline

Added On: 25/09/2019 14:15

Discipline Tags:

Dentistry Ceramics Health & Wellbeing Materials Science Life Sciences & Biotech

Technical Tags:

Diffraction microXRD