Abstract
In this study, the optical properties of indirect dental restorations based on polyetherketoneketone (PEKK), zirconia (YZ), and nickel-chromium (Ni-Cr) veneered with composite were compared. Based on the spectral reflectance, the CIE L*a*b* color coordinates, the color difference (??E), the opacity and the translucency parameter (TP) were determined using a spectrophotometer equipped with a D65 illuminant. The PEKK and Ni-Cr groups demonstrated similar CIE L*a*b* color values on white and black backgrounds. However, the zirconia group on a white backgrounds showed a slight shift in values towards red-yellow shades. The highest recorded ???E values were 1.3 and 1.61 between PEKK and YZ groups, and Ni-Cr and YZ groups respectively. The opacity and translucency (TP) parameters were consistent with the spectral reflectance data, with the Ni-Cr and PEKK groups being completely opaque (100% and 0 TP). It has been shown that the use of the same indirect light-cured composite veneer with different substructure materials has no clinical effect on the esthetics of the final restoration.