• Textile Coloration and Finishing
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• v.24 no.4
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• pp.305-312
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• 2012

In this study, we investigated the effects of oxidative permanent hair coloring agents on the dyeability and the damage of human hair. p-phenylenediamine and toluene-2.5-diamine sulfate were used as a hair coloring agent precursers. The degree of dyeability was checked by the change of CIELAB $L^*$ value according to dyeing time. And the damage of hair was evaluated by the tensile strength and morphological change of hair in SEM. When the hair was dyed, the CIELAB $L^*$ value was decreased with dyeing time regardless of the type of precursers. But when the hair was dyed after nutritional treatment, the CIELAB $L^*$ value showed lower level. This means that the nutritional treatment covers the scale of hair and protects the hair from the chemicals.

• Journal of the Society of Cosmetic Scientists of Korea
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• v.37 no.2
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• pp.121-127
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• 2011

Skin darkness is the source of trouble to many women. Skin darkness is the state that while skin redness and brightness are reduced, skin yellowness is increased. Skin translucency which is measured by skin color, especially brightness is an another expression of skin darkness. Skin brightness is usually expressed by L value of $L^{*} \;a^{*}\; b^{*}$ (CIELAB color space system). However, it is hard to find the relationship between L value and perceptive efficacy such as translucency because the L value is just a factor of evaluation of skin darkness. The skin with high translucency has high scattering reflective light value than low value. In this study, we measured the skin translucency of 20 ~ 30 ages men and women face by both our designed previous device which use polarized light to detect surface and scatter reflective light independently and $Lumiscan^{TM}$ which is improved designed to confirm our new device working ability by calculation of relationship between trnaslucency and scattering reflective light value. The result of this study indicate that there is a high correlation (R = 0.732, p < 0.01) between translucency and scattering reflective light value, and suggest that $Lumiscan^{TM}$ is portable and easy measuring device more that previous device.

• The Journal of Advanced Prosthodontics
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• v.10 no.6
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• pp.422-429
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• 2018

PURPOSE. Accurate color matching of maxillofacial prostheses to skin is important for esthetics. A computerized color matching system specific to human skin has recently been developed. The purpose of this study was to evaluate the accuracy in color and translucency matching of the computerized color matching system across different skin colors. MATERIALS AND METHODS. The silicone was colored to simulate 28 different skin colors (n=5) to serve as "target skin colors". Using a spectrocolorometer (e-skin), color codes were determined for "replicate skin color" fabrication. CIELAB Delta-E between target skin color-replicate skin color pairs and translucency parameter were calculated. CIELAB Delta-E values were compared with one-way ANOVA and Tukey multiple-comparison. The agreement between $L^*$, $a^*$, $b^*$ and translucency parameter of target skin colors and replicate skin color were calculated by a two-way mixed average measures intraclass correlation coefficient. Translucency parameter of target skin color- replicate skin color pairs were compared with Paired t-test (${\alpha}=.05$). RESULTS. The mean CIELAB Delta-E value was 3.83 and significant differences were found among colors. The intraclass correlation coefficient showed excellent reliability for $L^*$, $a^*$, $b^*$ and good reliability for translucency parameter (P<.001). The mean translucency parameter of replicate skin colors was significantly higher than that of translucency parameter. CONCLUSION. The computerized color matching system specific to human skin was found to be reliable in terms of color and translucency between target skin colors and replicate skin color.

• Restorative Dentistry and Endodontics
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• v.22 no.1
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• pp.358-373
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• 1997

Resin modified glass ionomers were introduced in 1988 to overcome the problems of moisture sensitivity and low early mechanical strength of conventional glass ionomers and to maintain their clinical advantages. The purpose of this study was to evaluate the color stability of four resin modified glass ionomers(Fuji II LC, Vitremer, Dyract and VariGlass), one resin composite material(Z-100), and one conventional glass ionomer(GC Fuji II) under several conditions. These conditions were as follows: 1) before curing, 2) after curing, 3) after polishing, 4) after 500 thermocycling, 5) after 1,000 thermocycling, 6) after 1,500 thermocycling and 7) after 2,000 thermocycling. Three specimens of each material/shade combination were made. Materials were condensed into metal mold with a diameter of 10 mm and a thickness of 2.0 mm, and were pressed between glass plates. The material was polymerized using a light polymerizing unit(Visilux II, 3M, USA). After removal of excess, the surface was polished sequentially on wet sandpapers. A reflection spectrophotometer(Model TC-6FX, Tokyo Denshoku Co., Japan) was used to determine CIELAB coordinates($L^*,a^*$ and $b^*$) of each specimen. CIE standard illumination C was used as the light source. The results were as follows : 1. In comparing different shades of same material, CIELAB color difference(${\Delta}E^*$) value was not significantly different from each other(p>0.05). 2. CIELAB color difference(${\Delta}E^*$) values between after-curing and after-polishing were ranged from 5.53 to 27.08. These values were higher than those of other condition combinations. 3. CIELAB color difference(${\Delta}E^*$) values between before-thermocycling and after-thermocycling were ranged from 1.40 to 7.81. Despite the number of thermocycling increased, CIELAB color difference(${\Delta}E^*$) value was low. 4. The color stability of resin modified glass ionomers was more stable than that of conventional glass ionomers but less stable than that of Z100.

• Restorative Dentistry and Endodontics
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• v.16 no.1
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• pp.1-5
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• 1991

The purpose of this study was to investigate the color stability of 2 light - polymerized veneer resins and 3 heat - polymerized veneer resins. Five specimen discs of each brand were immersed in distilled water at $37^{\circ}C$, in darkroom for 120 days. The distilled water was changed on every third day to prevent contamination from micro - organisms. The color characteristics of all the samples were measured by computer controlled spectrophotometer. The appearence was characterized by means of the $L^*$, $a^*$ and $b^*$ uniform color space(CIELAB) and total color difference was calculated. The following results were obtained 1) ${\Delta}E^*ab$ - value in all brand except IS is were greater than 1 perceptable in visual evaluation. 2) ${\Delta}E^*ab$ - value in VI, IS and VG were lower than upper limit of acceptablilty(3.3 in ${\Delta}E^*ab$). DC was the worst in color stability and was changed into yellow color.

• The Journal of Korean Academy of Prosthodontics
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• v.37 no.4
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• pp.425-432
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• 1999

The purpose of this study is to evaluate the color differences that can exist between different brands of dentin porcelain having identical shade designations. The instrumental colorimetric technique was used to determine these differences. The three brands of dentin porcelain used were Vita VMK-68, Shofu Vintage, and Ceramco II. The three shades selected were the Vita Lumin shades A2, B2, and C2. The color difference values were compared with each other using $L^*,\;a^*,\;b^*$, three variables of the CIELAB color system, and ${\Delta}E$. The results of this study were as follows: 1 Corresponding shades of different brands of dentin porcelain produced different $L^*,\;a^*,\;b^*$ values. 2. The greatest ${\Delta}E$ value in corresponding shade was found to exist between Ceramco II and Shofu Vintage, followed by between Vita VMK-68 and Ceramco II, and then between Vita VMK-68 and Shofu Vintage. 3. The ${\Delta}E$ values in shade C2 were mainly influenced by ${\Delta}L^*$ value ; however none of ${\Delta}L^*,\;{\Delta}a^*,\;{\Delta}b^*$ values had greater influence on ${\Delta}E$ values than the others in shade A2, B2. 4. Shofu Vintage had the highest $b^*$ value, followed by Vita VMK-68, and then Ceramco II.

• The Research Journal of the Costume Culture
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• v.23 no.5
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• pp.768-777
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• 2015

In this study, the dyeing of silk fabric with Polygonum cuspidatum extracts was investigated. The contents of this study are as follows. First, the proper dyeing conditions were investigated by measuring the dye uptake (K/S value) that depended on the dyeing conditions when silk fabric was dyed with Polygonum cuspidatum extract. Second, the brightness (L), hue, and chroma differences that appear after mordanting with Al, Cu and Fe were investigated by measuring the CIELAB and Munsell values. And third, the colorfastness and antibacterial property were measured. When the silk fabric was dyed with Polygonum cuspidatum extract, the proper dyeing conditions were a colorant concentration of 90% v/v, a dyeing of time 100 minutes, a dyeing temperature of $70^{\circ}C$, and a dyeing of pH 3. In mordanting methods, the dyeabilities of post-mordanting were higher than those of premordanting. The hue value displayed yellow (Y) and yellow-red (YR) in cases of pre and post mordanting. The C value decreased by the mordanting of Polygonum cuspidatum extracts. Generally the colorfastness of mordanted fabrics was improved by mordanting. The dyed fabrics showed a 90.6% of Staphylococcus aureus reduction rate, and the dyed and mordanted fabrics showed 97.1% bacteria reduction rate. The dyed and mordanted fabrics showed above 90.5% Klebsiella pneumoniae reduction rate, and Cu mordant revealed the most effective bacterial reduction.

• International Journal of Oral Biology
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• v.41 no.4
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• pp.243-251
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• 2016

This study was undertaken to achieve a high bleaching efficacy with plasma, through longer application and reparative bleaching processes, by different shade evaluation methods. Extracted human teeth were divided into 6 groups (n=10). All teeth were treated in pairs. Low concentration of 15% carbamide peroxide (CP) was applied, with and without plasma, for 10, 20, and 30-min tooth bleaching, respectively. The bleaching procedure was repeated once daily for four days. The teeth were maintained in a moist environment provided by artificial saliva. The Vitapan Classical shade guide and Commission Internationale de L'Eclairage (CIELAB) color system were collectively used to measure the bleaching efficacy. Color evaluation was statistically analyzed using Student t-test and one-way analysis of variance (ANOVA) complemented by Tukey's test. Combining the plasma with 15% CP showed significantly greater color changes compared to bleaching without plasma (p<0.05). A high bleaching efficacy with plasma is proportional to the repetitive application and the treatment time. A 30-min application with plasma provided the best bleaching. Repetitive bleaching showed lower probability of color relapse of the bleached tooth. The color change by shade guide correlated with the changes in CIELAB color system. A value of 1 color change units (CCU) conversion factor for overall color change (${\Delta}E$) values comparisons was 3.724 values. The two measuring methods provide a more accurate correspondence of color change. The repetitive and longer application for tooth bleaching, combined with plasma, has a strong bleaching effect and produces whiter teeth.

• Journal of the Society of Cosmetic Scientists of Korea
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• v.36 no.4
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• pp.253-258
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• 2010

Until now, evaluating the efficacy of brightening mainly depends on total reflective light measurement. For example, SHV (Saturation, Hue, Value), $L^*$ $a^*$ $b^*$ (CIELAB color space system) color space system was used and lightness and saturation changes were chosen as major parameters for evaluating brightening effect. However, those parameters were calculated from total reflective light on the skin and it is hard to evaluate perceptive efficacy such as luminescence, and glossy. In this research, we applied new method for estimating change of luminescence of skin by using 'Lumiscan' which uses polarized light for detecting surface and inside reflective light independently. We also tested 15 different parameters for finding correlations between luminescence and those parameters. As a results, our 2 different brightening products showed 5 ~ 9 % increase of luminescence at 4 and 8 weeks. And we also found that skin roughness (-28 %), melanin index (-17 %), redness (-7 %), hydration (15 %), and lightness (6 %) were related to luminescence of skin.

• Journal of Korean Dental Science
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• v.16 no.2
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• pp.192-203
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• 2023

Purpose: This study is to investigate the distribution of natural tooth shades in the Korean elderly population to quantify the correlation and changes of tooth color with age and gender. In addition, the possible effects of habits on tooth color were assessed. Materials and Methods: The tooth color of one of the maxillary central incisors of 200 Korean individuals aged 50 to 89 years, males and female, was measured using the portable intraoral spectrophotometer (VITA Easyshade V). CIELab and CIELCh color coordinates were recorded. We conducted the survey about the tobacco smoking, chronic disease, medication, eating habits, oral health behaviors and satisfaction with tooth color. Experimental data were statistically analyzed by using the t-test (P<0.05), two-way analysis of variance and Pearson's correlation test. Result: The most frequent color in the Korean elderly population was 3M3 & A3.5 shade. L^* and h^* values decreased, whereas C^*, a^* and b^* values increased progressively with age. There was a significant interaction between age and color coordinates for b^* values (r=0.245, P<0.05). Males generally have significantly higher C^*, a^*, b^* values and lower L^*, h^* value compared to females. Individuals who consumed alcohol had a higher L^* value (P<0.05). Conclusion: Within the limitation of this study, the central incisors were getting darker, more reddish, and yellowish with age. Information on the chromatic range of natural teeth by age and gender could help to select colors for esthetic dental restorations.