Color Evaluation of Porcelain Laminate Veneer Crown Color Evaluation by Color Depth (Rabe θ Value)

• Published in: Nihon Hotetsu Shika Gakkai Zasshi Vol. 39; no. 1; pp. 196 - 199
• Main Authors: Sawafuji, Futoshi, Shiraishi, Akira, Tsuchitoi, Hiroshi, Satodate, Tamaki, Ishikawa-Nagai, Shigemi, Ishibashi, Kanji
• Format: Journal Article
• Language: Japanese; English
• Published: Japan Prosthodontic Society 01.02.1995
• Subjects: color depth (Rabe θ value); discolored teeth; non-contact type spectrophotometer; porcelain laminate veneer crown
• ISSN: 0389-5386; 1883-177X
• DOI: 10.2186/jjps.39.196

Restoration of discolored teeth to a more natural color provides the patient with not only a harmonious oral appearance, but also a feeling of self-esteem and psycological satisfaction. Porcelain laminate veneer crowns, which do not require much tooth reduction, have drawn much attention as a type of prosthesis which is capable of restoring discolored teeth while maintaining its original occlusion. However, due to the thinness of the laminate veneer crowns, it is difficult to hide the original color of the tooth abutment while giving it a semi-transparent natural appearance. Thus a more objective method of evaluating the color of discolored teeth by using a non-contact type spectrophotometer was undertaken, and the measured color was evaluated in terms of the CIELab system, Munsell system, and a new index involving color depth which will be referred to as the Rabe θ value. Results indicated that it is possible to identify the color of teeth using the Rabe θ value, and that color variation between those teeth having natural tooth color to those having discoloration are clearly distinguishable by means of this index. Futhermore, by measuring the Rabe θ value of a tooth before and after placement of a porcelain laminate veneer crown, it was possible to determine the absolute color value of the tooth itself.