Color Stability of Pressed Lithium-Disilicate Ceramics Under Repeated Firings Evaluated by Different Methods
The International Journal of Prosthodontics
|March 13, 2024
Summary
Repeated firing cycles cause significant color changes in lithium-disilicate ceramics, but these are clinically acceptable. Different measurement instruments also show notable variations in color analysis.
Area of Science:
- Dental Materials Science
- Ceramic Restorations
- Colorimetry
Background:
- Lithium-disilicate ceramics are widely used in dental restorations.
- Repeated firing cycles can potentially alter the color stability of ceramic materials.
- Accurate color assessment is crucial for achieving esthetic outcomes in dentistry.
Purpose of the Study:
- To quantify and compare color differences in pressed lithium-disilicate ceramic specimens after multiple firing cycles.
- To evaluate the correlation between color differences (CIEDE2000) measured by different instruments: X-Rite Color i5 spectrophotometer, VITA EasyShade Advance 4.0, and Adobe Photoshop.
Main Methods:
- Thirty-six lithium-disilicate tile specimens (monochromatic and multichromatic) were subjected to seven repeated firing cycles.
- Color analysis (CIE L*a*b*) was performed after the 1st, 2nd, 3rd, 5th, and 7th firing cycles.
- Color differences (CIE DE*2000) were calculated using data from spectrophotometer, digital shade guide, and image analysis software.
Main Results:
- Multiple firing cycles resulted in statistically significant color differences (ΔE*00) in lithium-disilicate specimens (P < .001).
- Significant differences in color evaluation were observed between different shade groups and measurement instruments (P < .05).
- Interactive effects between shades, firing cycles, and instruments also showed statistical significance (P < .05).
Conclusions:
- Pressed lithium-disilicate ceramics exhibit significant color alterations after repeated firing cycles.
- Despite statistically significant differences, the observed color changes are considered clinically acceptable.
- Discrepancies among measurement instruments for CIE L*a*b* values exist but remain within human perceptible tolerance.
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