[Colorimetric studies on hiding effect of Cosmotech porcelain for laminate restoration].

The hiding effect on color tone of discolored teeth restored with ceramic laminate veneer crown was examined. Translucent (T1, T2), Enamel (E1, E2, E3), Dentin (DA2, DA3, DB2, DB3), Masking dentin (MDA2, MDA3, MDB2, MDB3) in 13 colors and Modifire (M61, M62, M65, M66, M67, M68, M69, M70, M79) in 7 colors of the ceramic materials (Cosmotech porcelain G C Co., Ltd) were examined in this experiments. The colorimetric examination of the color tone backing with the white or black color was carried out by testing for color difference (delta E*ab), value difference (delta L*), chrom and hue of the samples. The result obtained were as follows; 1. Color difference was higher in order of T2 greater than T1 in Translucent greater than E1 greater than E3 greater than E2 in Enamel greater than DB3 greater than DA2 greater than DA3 greater than DB2 in Dentin greater than MDB3 greater than MDA2 greater than MDB2 greater than MDA3 in Masking dentin, and M69 greater than M79 greater than M70 greater than M68 greater than M66 greater than M61 greater than M62 greater than M67 greater than M65 in Modifire. 2. Value difference was higher in order of T2 greater than T1 in Translucent greater than E1 greater than E3 greater than E2 in Enamel greater than DB3 greater than DA2 greater than DB2 greater than DA3 in Dentin greater than MDA2 greater than MDB3 greater than MDB2 greater than MDA3 in Masking dentin, and M69 greater than M70 greater than M79 greater than M68 greater than M66 greater than M61 greater than M67 greater than M65 greater than M62 in Modifire.(ABSTRACT TRUNCATED AT 250 WORDS)

Study of estimation of color recognition on the dentist. On the ability of subjects to discriminate color in terms of hue, value and chroma.

The tooth crown color space model was manufactured and the improvement of the color representation and communication on the dental clinic have been trying. The study of color discrimination by dentist and student viewing with the use of tooth crown color chips reported here in basic knowledge on the color sensitivity of human eye. The test card were 55 x 90 mm in size and the color chip, 5 x 10 mm. The paired color chips were placed on the test card to have a 2 mm distance between them. Color difference of two tooth crown color chips on the test cards was 3.5 (delta E*ab), the combination of hue, value and chroma was constant of all cards. The subjects were 22 people, 6 dentists and 16 dental school students with normal color sensibility. In proportion of method of comparison for surface color (JIS Z 8723), the subject observed the test card which were different of hue, value and chroma on the their naked-eye, were investigated to evaluate their judgement of the test cards. The following results were obtained. The standard of judgment for the color discrimination was made firstly in terms of hue, secondly in terms of value, and thirdly in terms of chroma.