J Dent Rehabil Appl Sci.  2020 Mar;36(1):41-47. 10.14368/jdras.2020.36.1.41.

Flexural strength and reliability of highly translucent colored zirconia

  • 1Department of Prosthodontics, College of Dentistry, Wonkwang University, Iksan, Republic of Korea


The purpose of this study was to evaluate the flexural strength and reliability of highly translucent colored zirconia for all ceramic restoration.
Materials and Methods
Bar-shaped specimens (25 × 4 × 2.5 mm) were prepared from highly translucent monolithic zirconia. Three experimental groups were set up according to color (shade A0, A1, and A3). For each group, 20 specimens were prepared. Flexural strength was determined using a 3-point flexural test and results were analyzed with one-way ANOVA test. Weibull statistical analysis provided 2 parameter estimates: Weibull modulus and characteristic strength. X-ray diffraction (XRD) analysis was performed.
There was statistically significant difference between uncolored (Shade A0) and colored (shade A1 and A3) (P < 0.05), but there was no difference between colored groups (P > 0.05). The uncolored group had higher reliability compared with colored study groups. On x-ray diffraction analysis of each group, typical peaks of tetragonal phase appeared in all groups.
Within the limitations of this in vitro study, coloring highly translucent zirconia had significant effect on flexural strength and reliability. Therefore, clinicians should be careful when using highly translucent colored zirconia to prevent breakage of veneering ceramic and enhance aesthetics.


zirconia; translucency; color; flexural strength


  • Fig. 1 Zirconia specimens used in this study (shade A0, A1, A3).

  • Fig. 2 3- point flexural test. (A) Schematic diagram of specimens, (B) Universal testing machine.

  • Fig. 3 Weibull distributions. Curved lines 95% confidence limits. (A) Shade A0, (B) Shade A1, (C) Shade A3.

  • Fig. 4 X-ray diffraction peaks of zirconia specimen surface. (A) Shade A0, (B) Shade A1, (C) Shade A3.


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