Research into the colors of denture base resin--influence of differences in shade and thickness.

Much research has been done of color science relative to dentistry, but the amount of research applied to denture base resin is very small-there are only three papers, by KANEKO et al. [4, 5], IBUSUKI et al. [10], and POWERS and J.M. [11, 12] and most of these used the Munsell color comparison method. Therefore, the authors did experiments using measuring equipment which can produce objective results, and obtained the following conclusions : 1. The lightness of the resin decreased with increasing thickness.2. The color saturation of the resin was greatest when the thickness was 1.8 mm.3. A tendency for the hue to change from reddish-yellow to red and to reddish-purple was observed with increasing thickness.4. For the lightness of the resin, no influence was observed of the change in Shades No. 1 to No. 4. However, lightness was influenced by differences in the thickness of Shades No. 1 to No. 4, and also by differences in the shade as well as the thickness of Shades No. 6 to No. 9.