Nano-scale mechanical behavior of pre-crystallized CAD/CAM zirconia-reinforced lithium silicate glass ceramic

Springall, Gabriella A.C., and Yin, Ling (2018) Nano-scale mechanical behavior of pre-crystallized CAD/CAM zirconia-reinforced lithium silicate glass ceramic. Journal of the Mechanical Behavior of Biomedical Materials, 82. pp. 35-44.

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Abstract

This paper reports on the mechanical behavior of pre-crystallized CAD/CAM zirconia-reinforced lithium silicate glass ceramic (ZLS) using nanoindentation with a Berkovich diamond tip and in situ scanning probe microscopy (SPM). The indentation contact hardness, the elastic modulus, and the elasticity and plasticity of the material were determined using the Oliver-Pharr method, the Sakai model and the Meyer's law at peak loads of 2.5–10 mN and a loading rate of 0.5 mN/s. The load-displacement curves at all applied loads indicate that ZLS deformed plastically without fracture. The discrete discontinuities in the load-displacement curves might have arisen from the shear plane activation for plastic deformation. The measured hardness and elastic modulus were load-independent (ANOVA, p > 0.05), in ranges of 8.17 ± 1.23 GPa to 9.86 ± 1.24 GPa and 98.55 ± 7.38 GPa to 105.78 ± 9.98 GPa, respectively. The resistance to plasticity of ZLS significantly showed a second-order polynomial load relationship or a power law load dependency. Meanwhile, both the elastic and plastic displacements also significantly revealed power law load dependencies. However, the elastic and plastic deformation components were load-independent. Increased indentation loads resulted in significant decreases in the normalized elastic strain energy (p < 0.05) accompanied by significant increases in the normalized indentation absorbed energy (p < 0.05). The equivalent elasticity and plasticity of ZLS during indentation occurred at 7.5 mN. The outcomes of this study provide insights into fabrication and mechanical functions of ZLS restorations, particularly facilitating abrasive machining in dental CAD/CAM processing in the ductile regime.

Item ID: 53881
Item Type: Article (Research - C1)
ISSN: 1878-0180
Keywords: In-situ scanning probe microscopy, Load effect, Mechanical properties, Nanoindentation, Zirconia-reinforced lithium silicate glass ceramic
Copyright Information: © 2018 Elsevier Ltd. All rights reserved.
Funders: James Cook University (JCU)
Projects and Grants: JCU Collaboration Grants Scheme
Date Deposited: 06 Jun 2018 07:42
FoR Codes: 09 ENGINEERING > 0912 Materials Engineering > 091201 Ceramics @ 100%
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