Assessing Color Inconstancy of CAD/CAM Materials: Influence of CIE White LED Illuminants and Substrate Shade

Area of Science:

• Dental Materials Science
• Color Science
• Optical Engineering

Background:

• Color inconstancy is a significant challenge for dental restorations.
• High-translucency CAD/CAM materials are increasingly used, necessitating an understanding of their color behavior.

Purpose of the Study:

• To evaluate the color inconstancy of CAD/CAM materials under various CIE white LED illuminants and substrate shades.

Main Methods:

• Spectral reflectance factors of four CAD/CAM materials were measured on nine background shades.
• Color differences (ΔE₀₀) were computed using CIECAT16 under D65, A, and nine CIE white LED illuminants.
• Color variations were analyzed for lightness, chroma, and hue (%ΔL₀₀, %ΔC₀₀, %ΔH₀₀).

Main Results:

• Most materials showed acceptable color mismatch under specific LED illuminants (B3, B4, B5) and background shades (ND1-ND9), except for ND6.
• RGB illuminants resulted in unacceptable color differences (ΔE₀₀ > 5.4).
• Color differences were mainly attributed to changes in chroma and hue across all conditions.

Conclusions:

• CIE white LED illuminants and substrate shade significantly influence the color inconstancy of CAD/CAM materials.
• Accurate color appearance of restorations depends on considering both substrate shade and illuminant type.
• This is crucial for esthetic outcomes, especially for translucent restorations on dark or saturated abutment teeth.