Carrabba, M, Keeling, AJ orcid.org/0000-0003-4598-3744, Aziz, A et al. (4 more authors) (2017) Translucent zirconia in the ceramic scenario for monolithic restorations: A flexural strength and translucency comparison test. Journal of Dentistry, 60. pp. 70-76. ISSN 0300-5712
Abstract
Objective: To compare three different compositions of Yttria-Tetragonal Zirconia Polycrystal (Y-TZP) ceramic and a lithium disilicate ceramic in terms of flexural strength and translucency. Methods: Three zirconia materials of different composition and translucency, Aadva ST [ST], Aadva EI [EI] and Aadva NT [NT](GC Tech, Leuven, Belgium) were cut with a slow speed diamond saw into beams and tabs in order to obtain, after sintering, dimensions of 1.2 × 4.0 × 15.0 mm and 15.0 × 15.0 × 1.0 mm respectively. Blocks of IPS e.max CAD LT were cut and crystallized in the same shapes and dimensions and used as a reference group [LD]. Beams (n = 15) were tested in a universal testing machine for three-point bending strength. Critical fracture load was recorded in N, flexural strength (σ in MPa), Weibull modulus (m) and Weibull characteristic strength (σ0 in MPa) were then calculated. Tabs (n = 10) were measured with a spectrophotometer equipped with an integrating sphere. Contrast Ratios were calculated as CR = Yb/Yw. SEM of thermally etched samples coupled with lineal line analysis (n = 6) was used to measure the tested zirconia grain size. Data were statistically analyzed. Results: Differences in translucency, flexural strength and grain size were found to be statistically significant. CR increased and flexural strength decreased in the following order ST(σ 1215 ± 190 MPa, CR 0.74 ± 0.01) > EI(σ 983 ± 182 MPa, CR 0.69 ± 0.01) > NT(σ 539 ± 66 MPa, CR 0.65 ± 0.01) > LD (σ 377 ± 39 Mpa, CR 0.56 ± 0.02). The average grain size was different for the three zirconia samples with NT(558 ± 38 nm) > ST(445 ± 34 nm) > EI(284 ± 11 nm). Conclusions: The zirconia composition heavily influenced both the flexural strength and the translucency. Different percentages of Yittria and Alumina result in new materials with intermediate properties in between the conventional zirconia and lithium disilicate. Clinical indications for Zirconia Aadva NT should be limited up to three-unit span bridges.
Metadata
Item Type: | Article |
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Authors/Creators: |
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Copyright, Publisher and Additional Information: | © 2017 Published by Elsevier Ltd. This is an author produced version of a paper published in Journal of Dentistry. Uploaded in accordance with the publisher's self-archiving policy. |
Keywords: | Translucent Zirconia; Y-TZP; Lithium Disilicate; Contrast Ratio; Flexural Strength; Translucency; Monolithic restoration; Grain Size |
Dates: |
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Institution: | The University of Leeds |
Academic Units: | The University of Leeds > Faculty of Medicine and Health (Leeds) > School of Dentistry (Leeds) > Oral Biology (Leeds) The University of Leeds > Faculty of Medicine and Health (Leeds) > School of Dentistry (Leeds) > Restorative Dentistry (Leeds) |
Depositing User: | Symplectic Publications |
Date Deposited: | 07 Mar 2017 15:54 |
Last Modified: | 11 Oct 2020 13:40 |
Published Version: | https://doi.org/10.1016/j.jdent.2017.03.002 |
Status: | Published |
Publisher: | Elsevier |
Identification Number: | 10.1016/j.jdent.2017.03.002 |
Open Archives Initiative ID (OAI ID): | oai:eprints.whiterose.ac.uk:113328 |