J Korean Acad Prosthodont.  2011 Apr;49(2):120-127. 10.4047/jkap.2011.49.2.120.

Effects of chromium chloride addition on coloration and mechanical properties of 3Y-TZP

• Oh GJ
• Seo YJ
• Yun KD
• Lim HP
• Park SW
• Lee KK
• Lim TK
• Lee DJ

• KMID: 2196118
• DOI: http://doi.org/10.4047/jkap.2011.49.2.120

Abstract

PURPOSE
The purpose of this study was to examine the effects of chromium chloride addition on coloration, mechanical property and microstructure of 3Y-TZP.
MATERIALS AND METHODS
Chromium chloride was weighed as 0.06, 0.12, and 0.25 wt% and each measured amount was dissolved in alcohol. ZrO2 powder was mixed with each of the individual slurry to prepare chromium doped zirconia specimen. The color, physical properties and microstructure were observed after the zirconia specimen were sintered at 1450degrees C. In order to evaluate the color, spectrophotometer was used to analyze the value of L*, C*, a* and b*, after placing the specimen on a white plate, and measured according to the International Commission on Illumination (CIE) standard, Illuminant D65 and SCE system. The density was measured in the Archimedes method, while microstructures were evaluated by using the scanning electron microscopy (SEM) and XRD. Fracture toughness was calculated Vickers indentation method and indentation size was measured by using the optical microscope. The data were analyzed with 1-way ANOVA test (alpha= 0.05). The Tukey multiple comparison test was used for post hoc analysis.
RESULTS
1. Chromium chloride rendered zirconia a brownish color. While chromium chloride content was increased, the color of zirconia was changed from brownish to brownish-red. 2. Chromium chloride content was increased; density of the specimen was decreased. 3. More chromium chloride in the ratio showed increase size of grains. 4. But the addition of chromium chloride did not affect the crystal phase of zirconia, and all specimens showed tetragonal phase. 5. The chromium chloride in zirconia did not showed statistically significant difference in fracture toughness, but addition of 0.25 wt% showed a statistically significant difference (P<.05).
CONCLUSION
Based on the above results, this study suggests that chromium chlorides can make colored zirconia while adding in a liquid form. The new colored zirconia showed a slight difference in color to that of the natural tooth, nevertheless this material can be used as an all ceramic core material.

Keyword

Chromium chloride; Zirconia; Color; Mechanical properties; Microstructure

MeSH Terms

Ceramics
Edible Grain
Chlorides
Chromium
Chromium Compounds
Humans
Lighting
Microscopy, Electron, Scanning
Tooth
Zirconium
Ceramics
Chlorides
Chromium
Chromium Compounds
Zirconium

Figure

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  Fig. 1. Surface trace dimensions of Vickers indentation used to measure the half-diagonal (a) and the initial length (c).

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  Fig. 2. L∗-C∗ and a∗-b∗ color coordinates of sintered 3Y-TZP with different weight percents of chromium chloride.

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  Fig. 3. Mean density and relative density of sintered 3Y-TZP with different weight percents of chromium chloride.

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  Fig. 4. SEM images of sintered 3Y-TZP with different weight percents of chromium chloride. A: 0 wt%, B: 0.06 wt%, C: 0.12 wt%, D: 0.25wt%.

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  Fig. 5. XRD patterns of sintered 3Y-TZP with different weight percents of chromium chloride. (a) 0 wt%, (b) 0.06 wt%, (c) 0.12 wt%, and (d) 0.25wt%.

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  Fig. 6. Fracture toughness of sintered 3Y-TZP with different weight percents of chromium chloride.

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