Abstract
The purpose of this study was to compare the objective chromatical values of the primary teeth color of the Japanese children measured with the Murakami Color Research Laboratory Light Guided Color Difference Meter CD-270 using the improved light guide (Improved CD-270), the CD-270 using the CD-270light guide (CD-270) and the Nippon Denshoku Co. Color and Color Difference Meter 1001 DP using the 1001 DP light guide (1001 DP).
The diameter of the CD-270 light guide head whic h receives the light from the objects was 7 mm. The light was placed on objects with a 45° angle from the center of the light guide. The light from the objects was received by the circumferential part of the light guide (center-circumferent lighting system). However, the diameters of the light guide head of the Improved CD-270 and 1001DP were 2 mm and the light was placed on the objects from the circumferential part of the light guide and the light from the objects was received by the center of the light guide with a 0° angle (circumferent-center lighting system) suitable for measuring small objects such as primary teeth.
The normal primary anterior tooth colors of 30 Japanese children ranging from 3 years to 5 years 2 months of age (average; 3 years 11 months) were chromatically measured using the Improved CD-270. The data was compared with that of the chromatical measuring of 18 Japanese children aged 3 years 8 months to 6 years 6 months (average; 5 years) using the 1001 DP and 30 Japanese children aged 2 years 4 months to 6 years 5 months (average; 4 years 3 months)using the CD-270 which were reported on previously.
The following results were obtained.
1) The mean chromatical values of XYZ, L*a*b*, xy and VCH showed different value patterns among the measurements with the color differen c e meters.
2) The mean chromatical values of a*b* of the various kinds of primary anterior teeth measured with the Improved CD-270 were approximately z e r o and almost white, the same as the values measured with the 1001 DP.
3) However, the mean chromatical values of a*b* of the various kinds of primary anterior teeth measured with the CD-270 were higher and show ed different types of colors.
4) In the mean chromatical valucs, ΔE* between the upper primary central incisors and the other primary anterior teeth showed different values among the measurements with the color difference meters.
5) Chromatical values of the primary teeth color were influenced by the difference of the inserted light volume and sensitivity of the light guide caus e d by the diameter of the light guide head, the difference lighting system and the individual difference of the color difference meters and light guides.6) Additional basic study is required for clinical use of the light guided color difference meters.
