Bending strength of zirconia/porcelain functionally graded materials prepared using spark plasma sintering

Gakuji Tsukada; Hidekazu Sueyoshi; Hiroki Kamibayashi; Masayuki Tokuda; Mitsuo Torii

doi:10.1016/j.jdent.2014.09.012

Bending strength of zirconia/porcelain functionally graded materials prepared using spark plasma sintering

J Dent. 2014 Dec;42(12):1569-76. doi: 10.1016/j.jdent.2014.09.012. Epub 2014 Oct 2.

Authors

Gakuji Tsukada¹, Hidekazu Sueyoshi², Hiroki Kamibayashi², Masayuki Tokuda³, Mitsuo Torii³

Affiliations

¹ Department of Restorative Dentistry and Endodontology, Kagoshima University Graduate School of Medical and Dental Sciences, Sakuragaoka, Kagoshima, Japan. Electronic address: tsukada@dent.kagoshima-u.ac.jp.
² Department of Mechanical Engineering, Graduate School of Science and Engineering, Kagoshima University, Korimoto, Kagoshima, Japan.
³ Department of Restorative Dentistry and Endodontology, Kagoshima University Graduate School of Medical and Dental Sciences, Sakuragaoka, Kagoshima, Japan.

PMID: 25280989
DOI: 10.1016/j.jdent.2014.09.012

Abstract

Objectives: The purpose of this study was to fabricate functionally graded materials (FGMs) consisting of yttria-stabilised tetragonal zirconia polycrystal (Y-TZP) and porcelain using spark plasma sintering (SPS) and examine the influence of their microstructures and thermal stress on their bending strengths.

Methods: Two types of four-layered Y-TZP/porcelain FGMs having a constant layer thickness and a varying layer thickness, Y-TZP/porcelain composite materials having a microstructure corresponding to each layer in FGMs and monolithic materials of Y-TZP and porcelain were fabricated by SPS. The Y-TZP/porcelain volume fraction of each layer in FGMs was varied over 100/0-70/30. Three-point bending test, X-ray diffraction, density measurement, microstructure observation, and thermal stress estimation were performed to characterise the materials.

Results: The bending strength of the Y-TZP/porcelain composite materials decreased with the volume fraction of the porcelain. About FGMs, when the 100%Y-TZP layer was on the tensile stress side during the bending test, the bending strength was almost the same as that of the 100%Y-TZP monolithic material. On the other hand, when the 100%Y-TZP layer was on the compressive stress side, the bending strength of FGM having a constant layer thickness was almost the same as that of the 70%Y-TZP+30%porcelain composite material, while the bending strength of FGM with a varying layer thickness was significantly higher than that of the 70%Y-TZP+30%porcelain composite material.

Clinical significance: The FGMs prepared and analyzed in this research can potentially be used for crowns and bridges as well as for inlays and onlays.

Conclusion: The SPS method could effectively fabricate the Y-TZP/porcelain FGMs, and the bending strength results revealed that the graded structure was very efficient to raise the bending strength.

Keywords: Bending strength; Functionally graded material; Porcelain; Spark plasma sintering; Thermal stress; Y-TZP.

Publication types

Research Support, Non-U.S. Gov't

MeSH terms

Aluminum Silicates / chemistry
Ceramics / chemistry*
Dental Materials / chemistry*
Dental Porcelain / chemistry*
Elastic Modulus
Electrochemical Techniques
Humans
Materials Testing
Microscopy, Electron, Scanning
Particle Size
Plasma Gases / chemistry*
Pliability
Potassium Compounds / chemistry
Powders / chemistry
Pressure
Quartz / chemistry
Stress, Mechanical
Surface Properties
Temperature
Vacuum
X-Ray Diffraction
Yttrium / chemistry*
Zirconium / chemistry*

Substances

Aluminum Silicates
Dental Materials
Plasma Gases
Potassium Compounds
Powders
yttria stabilized tetragonal zirconia
Dental Porcelain
feldspar
Quartz
Yttrium
Zirconium