One of the most important parameters in shade matching is determination of the correct saturation and Chroma for the natural dentin. Most teeth have a Hue in the A range. Some authors have estimated that this is the case in 80% of teeth. Other authors have measured the Hue to be around 580 nm, meaning a red-orange Hue that corresponds to shades A2, A3, and A3.5.
Many modern esthetic composites only include shade A dentins in their systems.
Fig 11. Part of the color spectrum which comprises the dentin colors, very close to the “A” color of the Vita shade guide.
Fig 12. The average Hue of incisors and ca- nines is 580 nm (red-orange), which corresponds to the tones A2, A3, and A3.5 in the Vita shade guide.
Ideal Properties of a Composite Dentin
-High Young modulus
-Low refraction index
-Ability to opacify
-Efficient light transmission
A material with all these features would be an exact copy of the human dentin, which at present is not technically possible.
Where composite resins, acrylic resins, and ceramics fail currently is on the efficiency of light transmission; the composite is not able to opacify effectively without losing its translucence and light transmission properties.
Nonetheless, physical properties are improving as materials evolve. Fluorescence of materials has been calibrated to the natural teeth, and color properties have improved considerably over the last decade.
The choice of dentin composite currently is limited to the following properties: