Fracture Load of Different Zirconia Types: A Mastication Simulation Study

Awab Abdulmajeed; Taiseer Sulaiman; Aous Abdulmajeed; Sompop Bencharit; Timo Närhi

doi:10.1111/jopr.13242

Fracture Load of Different Zirconia Types: A Mastication Simulation Study

J Prosthodont. 2020 Dec;29(9):787-791. doi: 10.1111/jopr.13242. Epub 2020 Oct 6.

Authors

Awab Abdulmajeed^{1

2}, Taiseer Sulaiman³, Aous Abdulmajeed^{1

2}, Sompop Bencharit^{2

4}, Timo Närhi^{1

5}

Affiliations

¹ Department of Prosthetic Dentistry and Stomatognathic Physiology, Institute of Dentistry, University of Turku, Turku, Finland.
² Department of General Practice, School of Dentistry, Virginia Commonwealth University, Richmond, VA.
³ Division of Comprehensive Oral Health, Adams School of Dentistry, University of North Carolina, Chapel Hill, NC.
⁴ Department of Biomedical Engineering, College of Engineering, Virginia Commonwealth University, Richmond, VA.
⁵ City of Turku, Welfare Division, Turku, Finland.

PMID: 32840940
DOI: 10.1111/jopr.13242

Abstract

Purpose: To assess the effect of yttria mol% concentration and material thickness on the biaxial fracture load (N) of zirconia with and without mastication simulation.

Materials and methods: Disk-shaped specimens (N = 120) of 3 mol% yttria-partially stabilized zirconia, 3Y-PSZ (Katana High Translucent, Kuraray Noritake), 4 mol% yttria-partially stabilized zirconia, 4Y-PSZ (Katana Super Translucent Multi Layered) and 5 mol% Yttria-partially stabilized zirconia, 5Y-PSZ (Katana Ultra Translucent Multi Layered) were prepared to thicknesses of 0.7 and 1.2 mm. For each thickness, the biaxial fracture load (N) was measured with and without mastication simulation with 1.2 million cycles at a 110-N load and simultaneous thermal cycling at 5°C to 55°C. The data were analyzed by three-way Analysis of Variance (α = 0.05) and Tukey-Kramer adjusted multiple comparison test.

Results: Yttria mol% concentration and material thickness had a statistically significant effect on the mean biaxial fracture load (F = 388.16, p < 0.001 and F = 714.33, p < 0.001 respectively). The mean biaxial fracture load ranged from the highest to the lowest; 3Y-PSZ, 4Y-PSZ, and 5Y-PSZ (p = 0.012). The mean biaxial fracture load of the 1.2 mm thickness groups was significantly higher than 0.7 mm thickness at any given condition (p = 0.002). Not all specimens survived the mastication simulation protocol. Fifty percent of the 0.7-mm-thick 4Y-PSZ specimens, 70% of the 0.7-mm-thick 5Y-PSZ specimens and 20% of 1.2-mm-thick 5Y-PSZ specimens fractured during mastication simulation. Mastication simulation had no statistically significant effect on the biaxial fracture load (F = 1.24, p = 0.239) of the survived specimens.

Conclusions: Lowering yttria mol% concentration and increasing material thickness significantly increases the fracture load of zirconia. At 0.7 mm thickness, only 3Y-PSZ survived masticatory simulation. A minimum material thickness of 1.2 mm is required for 4Y-PSZ or 5Y-PSZ.

Keywords: Fatiguing; fracture load; mastication's simulation; material thickness; strength; yttria concentration; zirconia.

MeSH terms

Dental Materials*
Dental Stress Analysis
Mastication*
Materials Testing
Zirconium

Substances

Dental Materials
Zirconium
zirconium oxide