Color difference of four esthetic restorative materials by the illuminant

To determine the difference in lightness, chroma, hue angle and color of four kinds of esthetic restorative materials of the same shade designation by the change of standard illuminants of D65 (daylight), A (incandescent lamp) and F2 (fluorescent lamp).

Spectral reflectance and color of four resin composites, a glass ionomer, a resin-modified glass ionomer and a compomer of shade A2 were measured according to the CIELAB color scale relative to the illuminants D65, A and F2. Spectral reflectance curves were compared, and changes in lightness (deltaL*), chroma (deltaC*ab), hue angle (deltah degrees) and color (deltaE*ab) by the changes of illuminants from D65 to A or F2 were compared as "value relative to the illuminant A or F2 - value relative to the illuminant D65".

In curves of spectral reflectance, the curves were in the similar range of reflectance (%) except glass ionomer. Changes in lightness were low (0.42-1.27), and changes in chroma were 0.26-2.23 for both conditions. These values were different by the kind of materials. The magnitude of the changes in hue angle was the most prominent in both conditions and was significantly different by the illuminants of A and F2 (P< 0.05). The range of color difference was 1.13-3.02 in both conditions.