Masking Power of Dental Opaque Porcelains

A technique was developed to qualify the masking power of undiluted opaque dental porcelain by dilution of opaque powder with a clear glaze powder and by extrapolation of quantitative data gathered by reflectance spectrophotometry. Quantification of reflectance data was made on dilute opaque porcelains using the scattering and absorption coefficients in the Kubelka-Munk equation. Qualitative comparisons of undiluted opaque porcelains were made from quantitative data gathered from diluted opaque porcelains.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/67998/2/10.1177_00220345840630062601.pd

The Color Accuracy of the Kubelka-Munk Theory for Various Colorants in Maxillofacial Prosthetic Material

The reflectance model developed by Kubelka and Munk was evaluated for agreement in color prediction of thick pigmented samples and for linearity of optical absorption and scattering coefficients with concentration of colorant in maxillofacial elastomer. The colorants tested were generic opacifiers, dry mineral earth pigments, and fibrous colorants. Significant linear relationships were commonly found between the optical coefficients and the concentration of the colorants. These relationships indicated occasional optical interaction between the colorants and the elastomer. Color differences between theoretical and observed colors of the thick samples averaged 2.96, 3.47, and 1.60 for the opacifiers, mineral earth pigments, and fibrous colorants, respectively, when measured using the CIELAB uniform-color space. The agreement between theoretical and observed colors was significantly closer for the fibrous colorants than for the dry mineral earth pigments of the same labeled color.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/67968/2/10.1177_00220345870660090601.pd