A colorimetric study on the opague porcelain of porcelain fused-to-metal crowns. Part I. Hiding effect on the color of metal base in case of the yellow color opaque porcelain

Abstract

To clarify the color of porcelain fused to metal crowns, We examined opaque porcelain baked on a metal base using a color and color difference meter. The following types of materials were used in fabricating the sample:(1) 84.3% Au-Pt-Pd-Ag alloy, (2) 81.9% Pd-Cu-Ga alloy, (3) 77.0% Ni-Cr alloy, (4) Yellow color opaque porcelains; B1O, B2O, B3O and B4O. The hiding effect on the color of the metal base was examined.The following results were obtaind:1. The color of the opaque porcelain fused to the metal was affected by the opaque porcelain color in the case of a 0.10-0.20 mm thick opaque porcelain layer. The hiding effect on the color of the metal base was greater for dark than light colored opaque porcelain. Layers thicker than 0.25 mm were not affected by the opaque porcelain color.2. The color of opaque porcelain fused to the metal was affected by the metal color for 0.10-0.20 mm thick opaque porcelain layers. The hiding effect on the color of the metal base was as follows; Au-Pt-Pd-Ag alloy was the highest, followed by Ni-Cr alloy, with Pd-Cu-Ga alloy being the lowest. Layers thicker than 0.25mm were not affected by the metal color.