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Title: 0102 - Sandblasting Increases the Flexural Strength of Highly Translucent Zirconia

Authors:

Masanao Inokoshi (Presenter)
Tokyo Medical and Dental University

Makoto Shimizubata, Tokyo Medical and Dental University
Kosuke Nozaki, Tokyo Medical and Dental University
Tomohiro Takagaki, Tokyo Medical and Dental University
Fei Zhang, KU Leuven (University of Leuven)
Jozef Vleugels, KU Leuven (University of Leuven)
Bart Van Meerbeek, KU Leuven (University of Leuven)
Shunsuke Minakuchi, Tokyo Medical and Dental University

Abstract:

Objectives: To assess the influence of alumina sandblasting on the flexural strength of four highly translucent dental zirconia grades.

Methods: Fully sintered zirconia disk-shaped specimens (14.5-mm diameter; 1.2-mm thickness) of four yttria partially stabilized (Y-PSZ) highly translucent zirconia grades (KATANA HT, KATANA STML, KATANA UTML, all Kuraray Noritake; Zpex Smile, Tosoh) were sandblasted with 50-µm alumina (Al2O3) sand (Kulzer) or left ‘as-sintered’ (control) (n=10). For each zirconia grade, the surface roughness was assessed using 3D confocal laser microscopy, upon which the zirconia grades were statistically compared for surface roughness using a Kruskal-Wallis test. X-ray diffraction (XRD) with Rietveld analysis was used to assess the zirconia-phase composition. Micro-Raman spectroscopy (µRaman) was used to assess the potentially induced residual stresses. The biaxial flexural strength was measured using a universal material-testing machine, followed by Weibull analysis.

Results: The ‘Al2O3-sandblasted’ zirconia resulted in significantly higher Sa values than the ‘as-sintered’ zirconia. XRD with Rietveld analysis revealed that the ‘Al2O3-sandblasted’ KATANA HT contained monoclinic zirconia (m-ZrO2) phase (5.8 wt%). µRaman revealed the presence of residual compressive stresses on the sandblasted surface of all zirconia grades. Weibull analysis revealed that Al2O3-sandblasting decreased the Weibull modulus of three highly translucent zirconia grades (KATANA HT, KATANA STML and Zpex Smile) and resulted in a significantly higher characteristic strength for KATANA HT and Zpex Smile. Al2O3-sandblasting slightly increased the Weibull characteristic strength of KATANA STML and KATANA UTML.

Conclusions: ‘Al2O3-sandblasted’ surfaces have a higher surface roughness and higher compressive stress than the ‘as sintered’ surface for all highly translucent zirconia grades. Al2O3-sandblasting increased flexural strength but decreased the Weibull modulus.

This abstract is based on research that was funded entirely or partially by an outside source:
This work was supported by JSPS Grant-in-Aid for Scientific Research (C) 16K11622 and JSPS Grant-in-Aid for Young Scientists (B) 17K17153.

Disclosure Statement:
The submitter must disclose the names of the organizations with which any author have a relationship, the nature of the relationship, and the clinical or research area involved. The following is submitted: NONE

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