J Adv Prosthodont.  2014 Jun;6(3):224-232. 10.4047/jap.2014.6.3.224.

Biaxial flexural strength and phase transformation of Ce-TZP/Al2O3 and Y-TZP core materials after thermocycling and mechanical loading

• Bankoglu Gungor M
• Yilmaz H
• Aydin C
• Karakoca Nemli S
• Turhan Bal B
• Tiras T

• KMID: 2118234
• DOI: http://doi.org/10.4047/jap.2014.6.3.224

Abstract

PURPOSE
The purpose of the present study was to evaluate the effect of thermocycling and mechanical loading on the biaxial flexural strength and the phase transformation of one Ce-TZP/Al2O3 and two Y-TZP core materials.
MATERIALS AND METHODS
Thirty disc-shaped specimens were obtained from each material. The specimens were randomly divided into three groups (control, thermocycled, and mechanically loaded). Thermocycling was subjected in distilled water for 10000 cycles. Mechanical loading was subjected with 200 N loads at a frequency of 2 Hz for 100000 times. The mean biaxial flexural strength and phase transformation of the specimens were tested. The Weibull modulus, characteristic strength, 10%, 5% and 1% probabilities of failure were calculated using the biaxial flexural strength data.
RESULTS
The characteristic strengths of Ce-TZP/Al2O3 specimens were significantly higher in all groups compared with the other tested materials (P<.001). Statistical results of X-ray diffraction showed that thermocycling and mechanical loading did not affect the monoclinic phase content of the materials. According to Raman spectroscopy results, at the same point and the same material, mechanical loading significantly affected the phase fraction of all materials (P<.05).
CONCLUSION
It was concluded that thermocycling and mechanical loading did not show negative effect on the mean biaxial strength of the tested materials.

Keyword

Ce-TZP/AL2O3; Y-TZP; Phase transformation; Thermocycling; Mechanical loading; Characteristic strength

MeSH Terms

Spectrum Analysis, Raman
Water
X-Ray Diffraction
Water

Figure

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  Fig. 1 Placing test specimen on the supporting balls of the tension-compression machine.

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  Fig. 2 Schematic diagram of three points (p1, p2, p3) where Raman spectra taken from.

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  Fig. 3 Weibull moduli distribution of Cercon Base specimens.

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  Fig. 4 Weibull moduli distribution of Lava Plus specimens.

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  Fig. 5 Weibull moduli distribution of NanoZR specimens.

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  Fig. 6 XRD patterns of one of Cercon Base specimen from all experimental groups.

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  Fig. 7 XRD patterns of one of Lava Plus specimen from all experimental groups.

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  Fig. 8 XRD patterns of one of NanoZR specimen from all experimental groups.

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