• 한국염색가공학회지
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• 제24권4호
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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.

• 대한화장품학회지
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• 제37권2호
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• pp.121-127
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• 2011

미백과 더불어 피부 칙칙함은 많은 여성들의 고민거리다. 칙칙함이란 피부의 붉은 기와 광택이 감소하고, 노란기는 증가하며 피부의 명도가 저하되어 보이는 상태를 말하며, 최근까지 피부 칙칙함의 경우, 일반적으로 피부색 측정을 통해 명도, 색 불균일성 등으로 많이 평가하였다. 명도는 $L^{*} \;a^{*}\; b^{*}$ 표색계(CIELAB color space system)의 $L^{*}$로 나타낸다. 하지만 $L^{*}$값은 칙칙함 중 하나의 현상, 명도를 측정한 지표일 뿐만 아니라 칙칙함(투명감)같은 인지효능과의 연계점을 찾기 힘든 단점이 있다. 이에 투명감이 높은 피부(칙칙하지 않은 피부)는 동일한 광세기가 피부로 입사하였을 때 피부 내부로부터 빛이 많이 돌아오는 피부이고 이는 확산 반사광(내부 반사광)이 큰 피부라는 피부 투명감 측정 방법에 따라 편광기술을 이용한 자사 제작의 이전 투명감 측정 기기와 측정의 용이성과 휴대성을 개선한 $Lumiscan^{TM}$이라 명명한 신규기기를 개발, 기존 투명감 측정기기와 신규기기로 20 ~ 30대 남성과 여성의 얼굴 피부 투명도를 측정하여 육안을 통한 투명감과 확산반사광 값의 관계를 통해 신규기기의 성능을 확인하고자 하였다. 이번 연구에서 육안 평가와 신규기기의 확산 반사광 값 사이에 단순 비교가 아닌 강한 상관성(R = 0.732, p < 0.01)이 있음을 확인할 수 있었으며 이전 자사개발 기기가 지닌 낮은 휴대성과 측정의 불편함을 개선한 $Lumiscan^{TM}$의 성능평가를 확인할 수 있었다.

• The Journal of Advanced Prosthodontics
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• 제10권6호
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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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• 제22권1호
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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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• 제16권1호
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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.

• 대한치과보철학회지
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• 제37권4호
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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.

• 복식문화연구
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• 제23권5호
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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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• 제41권4호
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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.

• 대한화장품학회지
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• 제36권4호
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• pp.253-258
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• 2010

현재까지 피부 미백에 대한 평가는 피부 반사광 전체에 대한 분석이 주를 이루어 왔다. 그 예로 SHV (Saturation, Hue, Value), $L^*$ $a^*$ $b^*$ (CIELAB color space system) 등 색차계를 사용하여 검출된 빛을 몇 가지 기준으로 나누어 분석하는 방법이 이용되어왔으며, 밝기나 채도 변화를 기준으로 피부 미백을 평가해왔다. 하지만 이러한 기존의 미백 평가법들은 빛의 전체 피부 반사량을 통한 측정이라는 한계를 가지고 있어 투명감, 화사함, 윤기 등 소비자들이 원하는 새로운 미백 효능의 평가에는 사용하기 힘든 단점이 있었다. 이번 연구에서는 이전까지 정량적으로 표현하기 힘들었던 투명감에 대한 새로운 측정법을 활용하여 8주 동안 자사의 2가지 미백 제형 효능 평가에 사용하였으며, 이를 위해 루미스캔(Lumiscan$^{TM}$)이라고 명명된 편광을 활용한 각도별 반사광 측정 장치를 제작하여 실험에 활용하였다. 또한, 투명감 측정 이외에도 15가지 측정치에 대한 실험을 병행하여 투명감에 주요한 영향을 미치는 요소를 분석하고자 하였으며 결과적으로 자사의 2가지 미백 제형은 각각 4, 8주에 5 ~ 9 %의 투명도 개선을 보여주었다. 그리고 피부결(-28 %), 멜라닌(-17 %), 홍반(-7 %), 수분량(15 %), 피부 밝기(6 %) 등이 피부 투명감에 주요한 영향을 주는 요소라는 사실을 보여주었다.

• Journal of Korean Dental Science
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• 제16권2호
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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.