Tomofumi Sawada1, Christine Schille2, Judit Zöldföldi3, Ernst Schweizer4, Jürgen Geis-Gerstorfer5, Sebastian Spintzyk6. 1. Section Medical Materials Science & Technology, University Hospital Tübingen, Osianderstr. 2-8, 72076 Tübingen, Germany. Electronic address: Tomofumi.Sawada@med.uni-tuebingen.de. 2. Section Medical Materials Science & Technology, University Hospital Tübingen, Osianderstr. 2-8, 72076 Tübingen, Germany. Electronic address: christine.schille@med.uni-tuebingen.de. 3. Institute for Materials Science, University of Stuttgart, Pfaffenwaldring 2b, 70569 Stuttgart, Germany. Electronic address: judit.zoeldfoeldi@mpa.uni-stuttgart.de. 4. Section Medical Materials Science & Technology, University Hospital Tübingen, Osianderstr. 2-8, 72076 Tübingen, Germany. Electronic address: ernst.schweizer@med.uni-tuebingen.de. 5. Section Medical Materials Science & Technology, University Hospital Tübingen, Osianderstr. 2-8, 72076 Tübingen, Germany. Electronic address: geis-gerstorfer@mwt-tuebingen.de. 6. Section Medical Materials Science & Technology, University Hospital Tübingen, Osianderstr. 2-8, 72076 Tübingen, Germany. Electronic address: Sebastian.Spintzyk@med.uni-tuebingen.de.
Abstract
OBJECTIVES: To assess the influence of a surface conditioner applied to pre-sintered yttria-stabilized tetragonal zirconia polycrystal (Y-TZP) on the biaxial flexural strength and phase transformation. METHODS: Conditioner-coated specimens (12mm diameter×0.8mm thickness) were prepared by application of a slurry conditioner using a brush on pre-sintered Y-TZP discs, followed by sandblasting with 50-μm Al2O3 after sintering (C-SB) or no further treatment (C-NT). The remaining conditioner-free specimens were subjected to sandblasting before sintering (NC-SB) or were maintained without treatment (NC-NT). Surface roughness measurements and scanning electron microscopy (SEM) in conjunction with energy dispersive X-ray spectroscopy (SEM-EDX) were performed for surface characterizations. The phase transformation of Y-TZP was identified by X-ray diffraction (XRD), and the biaxial flexural strength was measured using the piston-on-three-ball test according to ISO 6872:2015. The data were analyzed using nonparametric Kruskal-Wallis tests and Weibull distributions with the maximum likelihood estimation. RESULTS: Sandblasting resulted in significantly rougher surfaces, irrespective of conditioner application. Conditioner layers were observed on surfaces in the C-NT and C-SB specimens. Monoclinic contents were present in a very small amount in the C-SB specimens. Both median biaxial flexural and characteristic strengths of all specimens exceeded ISO 6872:2015 requirements (Class 5: >800MPa), except the NC-SB specimens which showed significantly the lowest strength (p<0.001). Although no statistical difference was observed in Weibull modulus among the specimens (p=0.598), the NC-SB specimens showed the highest. SIGNIFICANCE: Surface conditioner application does not affect the biaxial flexural strength and phase stability of Y-TZP and can be considered practical for clinical use.
OBJECTIVES: To assess the influence of a surface conditioner applied to pre-sintered yttria-stabilized tetragonal zirconia polycrystal (Y-TZP) on the biaxial flexural strength and phase transformation. METHODS: Conditioner-coated specimens (12mm diameter×0.8mm thickness) were prepared by application of a slurry conditioner using a brush on pre-sintered Y-TZP discs, followed by sandblasting with 50-μm Al2O3 after sintering (C-SB) or no further treatment (C-NT). The remaining conditioner-free specimens were subjected to sandblasting before sintering (NC-SB) or were maintained without treatment (NC-NT). Surface roughness measurements and scanning electron microscopy (SEM) in conjunction with energy dispersive X-ray spectroscopy (SEM-EDX) were performed for surface characterizations. The phase transformation of Y-TZP was identified by X-ray diffraction (XRD), and the biaxial flexural strength was measured using the piston-on-three-ball test according to ISO 6872:2015. The data were analyzed using nonparametric Kruskal-Wallis tests and Weibull distributions with the maximum likelihood estimation. RESULTS: Sandblasting resulted in significantly rougher surfaces, irrespective of conditioner application. Conditioner layers were observed on surfaces in the C-NT and C-SB specimens. Monoclinic contents were present in a very small amount in the C-SB specimens. Both median biaxial flexural and characteristic strengths of all specimens exceeded ISO 6872:2015 requirements (Class 5: >800MPa), except the NC-SB specimens which showed significantly the lowest strength (p<0.001). Although no statistical difference was observed in Weibull modulus among the specimens (p=0.598), the NC-SB specimens showed the highest. SIGNIFICANCE: Surface conditioner application does not affect the biaxial flexural strength and phase stability of Y-TZP and can be considered practical for clinical use.
Authors: Stephanie Assimakopoulos Garófalo; Martin Wehner; Andreas Dohrn; Marin Dean Bilandžić; Christian Roos; Richard Johannes Wierichs; Hendrik Meyer-Lueckel; Ana Cecilia Corrêa Aranha; Marcella Esteves-Oliveira Journal: Clin Oral Investig Date: 2021-08-17 Impact factor: 3.606