Earticle

이 연구에서는 국가지정 목조건축문화유산 현장에서 수습한 등황 채색시료를 분석하여 특성을 규명하고 이를 근거로 채색기법을 재현하여 채색 기법에 따른 발색 및 색 안정성을 평가 하였다. 문화유산 현장에서 확인된 전통 등황 단청의 채색기법은 주로 백색 안료로 밑칠을 하고 등황을 중첩 채색하였다. 백색 안료에는 연백, 백토가 단독 또는 혼합 사용되었다. 이를 근거로 재현시편은 등황 하부에 연백과 백토 안료를 단독 또는 혼합하여 밑칠한 중첩채색 기법으로 제작하였다. 또한 대조군으로 백색 안료와 등황을 혼합하여 칠한 혼합채색 기법을 제작하고 재 현시편을 대상으로 촉진내후성시험을 실시하였다. 이 결과, 등황 채색시편은 색차값(ΔE)이 모 두 40이상으로 색 보존성이 취약하여 유기안료의 재료적 한계를 확인할 수 있었다. 그러나 시험 전후 모두 혼합채색에 비해 중첩채색의 황색도가 높고 특히 중첩채색 중에서도 밑칠로 연백을 사용할 때 황색도가 높았다. 이를 통해 밑칠로 연백을 사용하고 등황을 중첩채색한 기법의 발색 과 보존성이 좋은 것을 알 수 있었다.

This study, analyzed painted pigment samples to investigate the coloring characteristics of the organic pigment Deunghwang. In particular, reproduction specimens were prepared using traditional Dancheong samples, and color development and accelerated weathering tests were conducted to evaluate the color stability of Deunghwang as per different coloring techniques. The traditional painting technique of Deunghwang confirmed that cultural heritage sites primarily involved the application of a base coat with white pigment followed by an overlapping paint of Deunghwang. In terms of white pigment, either Yeonbaek, Baekto, or a combination of both was used. Consequently, the reproduction specimens were created using the overlapping coloring technique wherein either of Yeonbaek, Baekto, or a combination of both was applied on the lower part of Deunghwang. Further, a mixed coloring technique was developed by mixing a white pigment and Deunghwang as the control group. Thereafter, an accelerated weathering test was performed on the reproduction specimens to evaluate the coloring layer preservation. The weathering test results indicated that, the color difference value of the Deunghwang specimens exceeded a vlaue of 40(ΔE), indicating poor color stability, and confirming the material limitations of organic pigments. However, both before and after the test, the yellowness of the overlapping coloring was higher than that of the mixed coloring, particularly when using the Yeonbaek pigment as an undercoat in the overlapping coloring, Thus, we conclude that the technique of using the Yeonbaek pigment as a base coat for overlapping with Deunghwang facilitates good color development and preservation properties.

이 연구에서는 국가지정 목조건축문화유산 현장에서 수습한 청색 채색층의 표면상태, 색도 및 성분 정보를 파악하고, 채색 시편 단면의 하부 밑칠 성분을 근거로 재현 시편을 제작한 후 촉진내 후성시험을 통해 보존성 평가를 수행하였다. 문화유산 현장에서 확인된 청색 단청의 채색기법은 주 로 백색 안료로 밑칠을 하고 그 위에 청색 안료를 중첩하는 방식으로 확인되었다. 백색 안료는 백토 또는 연백이 사용되었다. 이를 근거로 재현 시편은 청색 안료 하부에 백토와 연백 안료 각각을 밑칠 한 중첩채색 기법으로 제작하였다. 청색 안료 종류에 따른 중첩 채색 시편의 초기 청색도는 석청, 군청, 회청 순으로 석청의 청색도가 높았다. 촉진내후성시험 후 색차 값(ΔE)의 평균은 석청 7.19, 회청 4.49, 군청 3.65으로, 군청의 색 안정성이 높았다. 석청 안료의 경우 청색도는 가장 높으나 색 안정성이 다른 안료에 비해 낮은 모습을 보였다. 밑칠 안료에 따른 색변화는 청색 안료 모두 연백보 다 백토를 사용한 시편이 적게 나타나, 백토 밑칠이 채색층의 내후성을 향상시키는 것을 알 수 있다. 문화유산 현장에서 청색 안료는 백토 밑칠 위에 중첩 채색된 사례가 48%로, 연백 밑칠(12%) 보다 높은 빈도를 보였다. 이번 연구를 통해 백토를 활용한 중첩 채색 기법이 청색 안료의 색 보존성을 높이는 데 효과적인 것을 입증할 수 있었다.

This study, investigated the surface condition, chromaticity, and composition of a blue painted layer recovered from the nationally designated wooden architectural and cultural heritage site. Reproduction specimens were then made based on the undercoat composition from a cross-section of the painted specimen and preservation properties were evaluated through an accelerated weathering test. In blue dancheong from cultural heritage sites, the painting technique mainly involved underpainting with white pigments and overpainting with blue pigments. The white pigments used were Baekto and Yeonbaek. Based on this, the reproduction specimens were made using the overlapping coloring t echnique, in w hich t he b lue pigment was applied over underlayers o f either B aekto or Yeonbaek. The initial blueness of the overlapping specimens was highest for Seokcheong, followed by Guncheong and Hoecheong. After accelerated weathering, the mean color difference(ΔE) was 7.19 for Seokcheong, 4.49 for Hoecheong, and 3.65 for Guncheong, with Guncheong demonstrating the highest color stability. While the initial blueness was the highest for Seokcheong, its color stability was lower than that of the other pigments. Specimens with Baekto undercoating showed less color change than those with Yeonbaek, indicating better weathering resistance. Field survey results showed that 4 8% o f the b lue painted layers w ere applied over a B aekto undercoat, a higher f requency t han the use of a Yeonbaek undercoat (12%). The results confirmed that using Baekto in overlapping coloring improved the color stability of blue pigments.

본 연구는 구강양치용액이 복합레진의 색조 안정성과 표면미세경도 및 표면조도에 미치는 영향에 대하여 알아보고 자 하였으며, 실험실 연구로 Filtek P60과 Filtek Z250의 두 종류의 복합레진으로 시편을 제작하였다. 각 시편은 10개씩 8개 그룹으로 나누었다. 실험전 모든 시편을 colorimater를 이용하여 색조(L*, a*, b*)를 측정하였다. 대조군으로 증류수, 실험군으로 무색소, 녹색 및 보라색을 띄는 시판 구강양치용액을 사용하여 14일간 색변화, 표면미세경도, 표면조도 등을 측정하여 수집된 자료들 분석하였다. 녹색 및 보라색을 띄는 구강양치용액에서 눈에 띄는 색변화를 보였고, 모든 구강양치 용액군에서 표면미세경도는 감소하고 표면조도는 거칠어진 양상이 관찰되었다. 따라서 구강양치용액을 2주 이상 장기간 사용하게 되면 복합레진 표면에 변화를 야기할 수 있으므로, 안전한 사용을 위하여 짧은 기간 사용을 권장해야 할 것으로 사료된다.

This study aimed to evaluate the effects of oral rinsing solution on the color stability, surface microhardness and surface roughness change of composite resin. In this in-vitro study, 80 disc-shaped specimens were fabricated of Filtek P60 and Filtek Z250(A2 shade). The samples of each group were randomly divided into eight subgroups (n=10). The baseline color values (L*, a*, b*) of each specimen were measured according to CIE LAB system using a colorimeter. After baseline color measurements, the control samples were immersed in distilled water and the test groups were immersed colorless, green and purple mouthrinses three times a day for thirty minutes. This process was repeated for two weeks. Green and purple oral rinsing solutions displayed color, microhardness and roughness change of all composite resin after immersion in the mouthrinses. Therefore, prescription of oral rinsing solution for a minimum of two weeks is a common practice, which may cause discoloration of aesthetic composite restorations of patients.

목적: 하이브리드 코팅 기술을 사용하여 전분을 마그네슘 미리스테이트(magnesium myristate) 및 라우릴 라이신(lauryl lysine)으로 코팅하여 메이크업 화장품용 분체 소재를 개발하였다. PlanCare는 내수성이 뛰어난 분체이며, Neo Beads는 플라스틱 비드를 대체 할 수 있는 소재로 기대된다. 두 소재 모두 생분해성이 뛰어나고 친환경적인 화장품 원료로서의 가능성을 갖고 있다. 방법: 생분해 성을 비교하기 위해 아밀레이즈를 이용한 전분 가수분해 실험과 세포 생존율 시험을 수행하였으며, 감자 전분과 비교하였다. 또한, 안정성 평가를 위해 시료를 4℃, 25℃, 55℃, -20℃ 및 자연광 환경에서 5개월간 보관한 후, 색차계를 이용하여 색 차이(ΔE)를 측 정하였다. 결과: 아밀레이즈 전분 가수분해 시험 결과, 하이브리드 코팅 기술을 적용한 마그네슘 미리스테이트 코팅 PlanCare는 전 분과 유사한 생분해능을 나타내었다. 다른 PlanCare 시료 및 Neo Beads 또한 생분해능이 확인되었다. 색차계 분석 결과, PlanCare 는 보관 온도 및 기간과 관계없이 5개월 동안 전분과 유사한 안정성을 유지하는 것으로 나타났다. Neo Beads 또한 모든 보관 조건 에서 안정성을 유지하였다. ΔE 값은 L*, a*, b*의 총 색 차이를 나타내며, 색 안정성 평가에 활용될 수 있다. 5개월간 ΔE 값을 비교 한 결과, 1.5-3.0 범위에서는 색 차이가 거의 인지되지 않는 것으로 나타났다. PlanCare 및 Neo Beads의 ΔE는 2.0 이하로 유지되 어 안정성이 확인되었다. 결론: 본 연구에서 PlanCare 및 Neo Beads는 친환경적 생분해능 특성을 갖춘 화장품 소재를 개발하였다. 미세플라스틱의 위험성에 대한 문제가 대두되어 미세플라스틱 대체에 집중하고 있는 화장품 산업사회에서 생분해성을 지닌 친환경 화장품 소재로 응용할 수 있는 가능성을 확인하였다.

Purpose: Starch was coated with magnesium myristate and lauroyl lysine using hybrid coating technology to develop powder materials for makeup cosmetics. PlanCare are water-resistant powders, and Neo Beads may replace plastic beads. Both are biodegradable and ecofriendly materials with potential applications in the cosmetic industry. Methods: Starch hydrolysis using amylase and cell viability test were conducted for comparison with starch. Stability test was conducted by measuring the color differences using a colorimeter after storing the samples for 5 months at 4°C, 25°C, 55°C, and −20°C and under daylight conditions. Results: The amylase assay confirmed that the powder material (PlanCare), coated with magnesium myristate using hybrid coating technology, exhibited a biodegradation rate similar to that of starch. The biodegradability of other PlanCare samples and Neo Beads was also demonstrated. Colorimetric analysis demonstrated that PlanCare maintained stability for 5 months, similar to starch, irrespective of storage temperature and duration. Neo Beads also remained stable irrespective of storage conditions. As the ΔE value represents the total color difference in L*, a*, and b*, it can be used to evaluate color stability. A 5-month comparison showed that it is generally difficult to perceive a range of 1.5–3.0. Both PlanCare and Neo Beads maintained ΔE values at <2.0, confirming their stability. Conclusion: Due to the increasing concerns on the risks posed by microplastics, the cosmetic industry is focusing on alternatives. PlanCare and Neo Beads demonstrated their potential as biodegradable and ecofriendly cosmetic materials.

目的: 利用混合涂层技术，淀粉被肉豆蔻酸镁和月桂酰赖氨酸包裹，开发出用于彩妆的粉末材料。PlanCare是 防水粉末，而Neo Beads可以替代塑料珠。这两种材料都是可生物降解的环保材料，在化妆品行业具有潜在的 应用前景。方法: 使用淀粉酶进行淀粉水解，并进行细胞活力测试，与淀粉进行比较。稳定性测试：将样品在 4℃、25℃、55℃、-20℃和日光条件下储存5个月后，用比色计测量色差。结果: 淀粉酶测定证实，采用混合包 衣技术包覆肉豆蔻酸镁的粉末材料(PlanCare)的生物降解速率与淀粉相似。本研究还证明了其他PlanCare样品 和Neo Beads的生物降解性。比色分析表明，PlanCare在5个月内保持稳定性，与淀粉相似，不受储存温度和储 存时间的影响。Neo Beads在任何储存条件下均保持稳定。由于ΔE值代表L*、a*和b*的总色差，因此可用于评 估颜色稳定性。5个月的比较表明，通常难以察觉1.5至3.0之间的色差。PlanCare和Neo Beads均将ΔE值保持 在<2.0，证明了它们的稳定性。结论: 由于人们日益担忧微塑料带来的风险，化妆品行业正致力于寻找替代品。 PlanCare和Neo Beads展示了其作为可生物降解、环保化妆品材料的潜力。

본 시험은 vitamin C와 E 급여가 한우 거세우 쇠고기의 보존에 미치는 영향을 규명하기 위하여 실시하였다. 시험구는 대조구(비타민 C 비급여 및 비타민 E 20 IU/kg feed), 비타민 C 급여구(비타민 C 0.1%/kg feed 및 비타민 E 20 IU/kg feed), 비타민 E 급여구(비타민 E 220 IU/kg feed) 및 비타민 C와 E 혼합 급여구(비타민 C 0.1%/kg feed 및 비타민 E 220 IU/kg feed)의 네 처리구로 나누어 출하전 90일 동안 사양시험을 실시하였고, 도축 후 5 에서 저장하면서 1, 3, 5, 7 및 10일째 배최장근의 pH, TBARS, 표면색, 육색소 분포, 보수력, 가열감량, 육즙손실 및 포장감량을 조사하였다.pH는 저장기간이 경과함에 따라 증가하였고, 비타민 C와 E 혼합 급여구가 저장 전 기간동안 높게 나타났다. 지방산패도는 저장기간이 경과함에 따라 증가하였고, 비타민 급여구가 대조구보다 낮았고, 특히 비타민 C와 E를 혼합하여 급여하였을 때 지방산패도가 낮았다. Hue angle은 저장기간이 경과함에 따라 높아졌고, 특히 대조구가 비타민 급여구보다 상당히 증가하였다. Metmyoglobin 함량은 저장기간이 경과할수록 증가하였고, 특히 대조구가 비타민 급여구보다 유의적(P < 0.05)으로 높았다.Oxymyoglobin 함량은 저장기간이 경과하면 감소하였으나, 비타민 E 또는 C와 E 혼합 급여구가 대조구보다 유의적(P < 0.05)으로 높았다. 이는 비타민 C와 E를 급여하면 쇠고기의 육색을 안정화시키는 것으로 사료된다. 보수력은 저장 7일째까지는 처리구간에 유의적인 차이는 없었고, 가열감량은 저장기간별로는 차이가 없었으나, 비타민 E 급여구 또는 비타민 C와 E 혼합 급여구가 대조구 및 비타민 C 급여구보다 저장 전기간 동안 유의적(P < 0.05)으로 높았으며, 육즙손실과 저장감량은 저장기간이 경과함에 따라 증가하는 경향을 나타내었다.그러므로 본 시험결과에 의하면 사료 중에 비타민 C 0.1% 또는 사료 kg당 비타민 E 220 IU를 첨가하면 지방산화가 지연되고, 또한 사료 중에 비타민 C 0.1%와 사료 kg당 비타민 E 220 IU를 함께 첨가해주면 육색이 안정화되는 것으로 사료된다.

This experiment was carried out to investigate the effects of dietary vitamin C and E on lipid oxidation and stability of color in Hanwoo steer beef. Thirty seven Hanwoo steers were randomly assigned to one of four treatments. The four treatments were control(vitamin E 20IU/kg feed), vitamin C(vitamin C 0.1%/kg feed and vitamin E 20IU/kg feed), vitamin E(vitamin E 220IU/kg feed) and vitamin C plus E(vitamin C 0.1%/kg feed and vitamin E 220IU/kg feed). Hanwoo steers were fed the experimental diets for 3 months at the last finishing period and pH, color, TBARS, concentration of myoglobin, water holding capacity, reduction by heat, drip loss and purge loss of longissimus dorsi were analyzed at 1, 3, 5, 7 and 10th day of storage, respectively.pH value, Hue angle, metmyoglobin concentration, TBARS, drip loss and purge loss in longissimus dorsi were increased as the storage period elapsed. However, water holding capacity in longissimus dorsi was decreased as the storage period elapsed. The animals fed the vitamin C plus E diet were higher in pH value and oxymyoglobin concentration, and lower in metmyoglobin concentration than in those fed the other diets during the whole storage period and lowest in TBARS. TBARS and Hue angle in longissimus dorsi were lower(P < 0.05) in the animals fed the vitamin-supplemented diets than in those fed the control diet. Reduction by heat in longissimus dorsi was higher(P < 0.05) in the animals fed the diets supplemented with vitamin E or vitamin C plus E than in those fed the control diet or vitamin C-supplemented diet.According to these results, it may be concluded that feeding the diets containing 0.1% vitamin C or 220IU vitamin E per kg feed or the diet mixed 0.1% vitamin C with 220IU vitamin E to Hanwoo steers can retard lipid oxidation of longissimus dorsi and stabilize beef color.

Purpose: This study was conducted to examine the color stability of temporary prosthetic materials for dental CADCAM. Method: 2 kinds of existing acrylic resin temporary filling materials and 2 kinds of polymer prosthetic materials for dental CAD-CAM were used for testing, and five specimens respectively were absorbed in soy sauce, red pepper paste, and coffee. A Chroma Meter was used as analysis equipment. The color change of the specimens was observed to calculate ΔE value throughout 2 days, 3 days, 4 days, and 5 days and this was analyzed and the following result was obtained. Results: Snap’s ΔE value was bigger than Vipi block(p<0.05). Red pepper paste had the largest impact on the color change of resin(ΔE), followed by soy sauce and coffee(p<0.000). With the passage of time, ΔE value was inversely(-) related and decreased somewhat(p<0.000).

This study was performed to evaluate the chemical stability of doxorubicin hydrochloride at concentration of 0.5 and 0.05 mg/mL in 0.9% sodium chloride injection, when stored in lightprotecting bags. The test samples were prepared in each concentration and then they were divided into three groups. Two groups were protected from light by light-protecting polyethylene bag - Group A(dark-brown color), Group B(jade/white double color) and one group was not protected from the normal fluorescent light-Group C. Chemical stability was assayed by HPLC initially and after 12, 24, 30 hours at room temperature. At 12, 24, 30 hours, the contents of doxorubicin hydrochloride 0.5 mg/mL were 92.69%, 88.35% and 79.90% for group A ; 91.67%, 86.09% and 76.82% for group B ; 89.75%, 83.73% and 76.40% for group C, respectively. At 12, 24, 30 hours, the contents of doxorubicin hydrochloride 0.05 mg/mL were 73.80%, 53.39% and 45.07% for group A ; 73.42%, 48.57% and 24.29% for group B ; 67.00%, 43.70% and 20.05% for group C, respectively. Doxorubicin hydrochloride 0.5 mg/mL in 0.9% sodium chloride injection was chemically stable(loss in potency of less then 10%) for 12 hours respectively, when stored in light-protecting polyethylene bag, while doxorubicin hydrochloride 0.05 mg/mL in 0.9% sodium chloride injection was unstable in all samples throughout the study. The greater rate of decomposition of doxorubicin hydrochloride occurred in the more diluted solution. In the same concentration, no significant difference of drug loss was observed between the groups of light-protecting polyethylene bags.

Purpose: This study aimed to evaluate the effect of postcuring conditions, such as variations in light intensity and curing time, on the color stability of resins used in three-dimensional (3D)-printed dental restorations. Methods: Using an liquid crystal display 3D printer, 81 specimens in the shape of a 10.0 mm×1.5 mm disk were produced according to the specified parameters. The printed specimens were postcured at various light intensities (17.76, 121.43, and 199.99 mW/cm2) and curing times (5, 10, and 20 minutes). Color was assessed using a color difference spectrophotometer (CM-3600A, Konica Minolta) based on the Lab* color space defined by the International Commission on Illumination, and the L*, a*, b*, C*, and H values and ΔE00 were analyzed. To evaluate the effect of postcuring conditions on the color changes, a twoway analysis of variance was conducted. Tukey’s post hoc test (α=0.05) was performed to assess significant differences. Results: The results showed significant differences in L*, a*, and ΔE00 values based on light exposure and curing time (p<0.001), whereas b* and C* values differed significantly (p<0.05). H values were not significantly different (p=0.231). Conclusion: This study demonstrated that light exposure and curing time significantly influenced the color stability of 3D-printed resin restorations. Thus, light exposure of Lv7 or lower and curing times of ≤10 minutes are recommended for optimal color stability.

Purpose: This study investigates the effect of repeated use of lithium disilicate glass-ceramics on color stability. Methods: In this study, 2 types of lithium disilicate glass-ceramics were used and they were divided into 4 groups after 1st, 2nd, 3rd, and 4th heat pressing. The L*, a*, and b* values of all specimens were measured using the VITA Easyshade Advance 4.0. These values was used to determine the ΔE value and transparency. IBM SPSS Statistics ver. 24.0, a statistical significance level of 0.05 and one-way ANOVA were used for all data. Results: In all groups, the L* and b* values were the lowest in the specimens subjected to the 4th heat pressing and the corresponding a* value was the highest. All specimens showed ΔE values of ≤3.3, indicating color changes that were not visible with the naked eye, and the color difference increased with the number of repeated heat pressing. The transparency of all specimens decreased as the number of repeated uses increased. Conclusion: According to the number of repeated heat pressing, the color difference of Rosetta SP (HASSBIO) was larger than that of IPS e.max Press (Ivoclar Vivadent), but it was clinically acceptable in all groups. Moreover, transparency decreased as the number of heat presses increased in all groups. According to the above findings, the lithium disilicate glass-ceramic has high color stability due to repeated heat pressing, implying that it can be used in clinical settings regularly.

In now days, it is necessary that actual color planning for the interior environmental design especially in hospital. The purpose of this study is psychological stability of color scheme characteristics focused on consultation-room in hospital through psychological stability color scheme of previous research, case study and questioned. The result of color image characteristics are as follows; First, a warm color and similarity harmony are most effective to psychological stability. Second, the relations between dominant color and subdominant color are very important for stability and main harmony of color scheme.

Purpose: The aim of study was to compare the dimensional stability of digitized dental stone replica using different color of gypsum materials using a white light scanner with three- dimensional software. Methods: A master model(500B-1, Nissin dental product, Japan) with the prepared lower full arch tooth was used. Several type stones(white, yellow, green) were used for 30 stone casts(10 casts each) duplicated a master model of mandible. The master model and the replicas were digitized with the non -contacting white light scanner to create 3-dimensional digital models. The linear distance between the reference points were measured and analyzed on the Delcam Copycad (Delcam plc, UK) 3D graphic software. One-way analysis of variance(ANOVA) combined with a Tukey multiple-range test were used to analysis the data( =0.05). Results: There were considerable differences in mean values between gypsum materials within each color(white, yellow, green), and this difference was statistically significant, p=0.001. Conclusion: Digitization of dental materials on optical scanner was affected by color. Three different color of gypsum materials showed clinically acceptable accuracies of full arch digital model produced by them. Besides, these results will have to be confirmed in further clinical studies.

본 연구는 컬러심리를 활용한 집단미술치료가 대학생의 취업스트레스와 정서안정에 미치는 효과를 알아보기 위한 것이다. 연구대상은 A시의 B대학교 3∼4학년 남, 녀 재학생들 중 취업 을 준비하고 있고 프로그램에 참여를 희망한 자들로 총 18명을 선정하여 실험집단 9명과 통제 집단 9명으로 무선으로 배치하였다. 연구기간은 2017년 5월 31일부터 8월 2일까지 실험집단에 한해서 주 1∼2회 90분씩 총 12회기의 컬러심리를 활용한 집단미술치료가 진행되었다. 결과분 석을 위하여 취업스트레스 척도와 빗속의 사람 그림검사, 정서안정 척도를 사전, 사후로 측정 한 결과를 양적으로 분석하였다. 본 연구의 결과는 첫째, 컬러심리를 활용한 집단미술치료가 실험집단의 취업스트레스 변화에 통계적으로 유의미한 효과를 보였다. 취업스트레스의 빗속의 사람 그림검사를 양적으로 분석한 결과 스트레스, 대처자원, 대처능력에서 모두 통계적으로 유 의미한 효과를 보였다. 둘째, 컬러심리를 활용한 집단미술치료가 실험집단의 정서안정 변화에 통계적으로 유의미한 효과를 보였다. 따라서 컬러심리를 활용한 집단미술치료 프로그램은 대학 생의 취업스트레스와 정서안정에 효과가 있었다.

The objective of this study is to understand the effects of group art therapy using color psychology on the employment stress and emotional stability of university students. Selecting total 18 volunteers hoping to participate in the program as people seeking for employment among male & female students in their 3rd-4th year of B University in A City, they were randomly arranged like nine students in an experimental group and another nine students in a control group. From May 31st to August 2nd 2017, total 12 sessions of group art therapy using color psychology were provided to the experimental group for 90 minutes/each session and 1-2 times a week. For the analysis of results, the pre/post measurements of employment stress scale, Person In The Rain Test, and emotional stability scale were quantitatively/qualitatively analyzed. The results of this study are like below. First, the group art therapy using color psychology had statistically significant effects on changes in the employment stress of the experimental group. In the results of quantitatively/qualitatively analyzing Person In the Rain (PITR) Test of employment stress, all the stress, coping resource, and coping ability showed statistically significant effects. Second, the group art therapy using color psychology had statistically significant effects on changes in the emotional stability of the experimental group. Thus, the group art therapy using color psychology had effects on the decrease of employment stress and the improvement of emotional stability of university students.

The objectives of this study were to examine changes in the color and antioxidant compounds of paprika powder under various conditions, as well as to establish the suitable conditions for drying and storage. Paprika was dried using the following methods: freeze-drying, vacuum drying, far infrared-ray drying, and hot-air drying. Measurements of the moisture content, color pigments, and antioxidant compounds (total carotenoids, capsanthin, ascorbic acid, and total polyphenols) were completed during 120 days of storage at 4 and30℃ . We found that drying methods, storage temperatures, and packaging materials affected the American Spice Trade Association (ASTA) and Hunter color values, as well as the antioxidant content of paprika powder. There was a high correlation (r=0.87, p<0.01) between the ASTA color and the a2/b2 value. The loss of red color was closely related to the reduction of moisture content (r=0.81, p<0.01) during storage. Drying paprika with a low temperature in the absence of air resulted in better retention of the carotenoids and ascorbic acid. Also, as the retention of the carotenoids and ascorbic acid increased, the stability of the red pigment increased. Freeze-drying was found to be the most suitable drying method for the stability of the antioxidant compounds and red pigment.

PURPOSE. The aim of this study was to investigate shade changes in fully- and pre-crystalized CAD-CAM lithium disilicate crowns after the required and additional firing processes. MATERIALS AND METHODS. One hundred and five crowns of shade A1 with high translucency were milled out of CAD-CAM lithium disilicate blocks and categorized as follows (n = 15): (1) restorations fabricated from Straumann n!ce with no additional sintering process; (2) restorations fabricated from Straumann n!ce with one additional sintering process; (3) restorations fabricated from Straumann n!ce with two additional sintering processes; (4) restorations fabricated from Amber Mill with one sintering process; (5) restorations fabricated from Amber Mill with two sintering processes; (6) restorations fabricated from IPS e.max CAD with one sintering process; (7) restorations fabricated from IPS e.max CAD with two sintering processes. All restorations were evaluated with a color imaging spectrophotometer. RESULTS. All restorations presented some color alteration from the original shade both after a single and after two firing processes. CONCLUSION. The required and additional sintering processes for restorations fabricated with chairside CAD-CAM lithium disilicate blocks cause an alteration of the original shade selected. Shade A1 high translucency restorations tend to change to a more yellowish B1 shade after a sintering process.

Purpose. This in-vitro study evaluated and compared the color stability of 3D-printed and conventional heat-polymerized acrylic resins following aging, mechanical brushing, and immersion in staining medium. Materials and methods. Forty disc-shaped specimens (10 mm in diameter and 3 mm thick) were prepared from two 3D-printed [DentaBASE (DB) and Denture 3D+ (D3D)] and one conventional polymethylmethacrylate (PMMA) denture materials. The specimens were thermo-cycled, subjected to mechanical brushing, and were immersed in either coffee, lemon juice, coke, or artificial saliva (AS) to simulate one and two years of oral use. Color measurements of the specimens were recorded by a spectrophotometer at baseline (T0), and after one (T1) and two years (T2) of simulation. The color changes (ΔE) were determined and also quantified according to the National Bureau of Standards (NBS) units. Descriptive statistics, followed by factorial ANOVA and Bonferroni post-hoc test (α=.05), were applied for data analysis. Results. The independent factors, namely material, staining medium, and immersion time, and interaction among these factors significantly influenced ΔE (P<.009). Irrespective of the materials, treatments, and time, the highest and the lowest mean ΔEs were observed for PMMA in lemon juice (4.58 ± 1.30) and DB in AS (0.41 ± 0.18), respectively. Regarding the material type, PMMA demonstrated the highest mean ΔE (2.31 ± 1.37), followed by D3D (1.67 ± 0.66), and DB (0.85 ± 0.52), and the difference in ΔE between the materials were statistically significant (P<.001). All the specimens demonstrated a decreased color changes at T2 compared to T1, and this difference in mean ΔE was statistically significant (P<.001). Conclusion. The color changes of 3D-printed denture resins were low compared to conventional heat polymerized PMMA. All the tested materials, irrespective of the staining medium used, demonstrated a significant decrease in ΔE values over time.

목적: 본 연구는 다양한 색소에 침전된 Dentca 3D 프린팅 인공치의 색 안정성을 4가지 전통적인 인공치와 비교하여 평가하기 위함이다. 재료 및 방법: 4가지 전통적인 기성 인공치(Surpass, GC, Artic 6, Heraeus Kulzer, Premium 6, Heraeus Kulzer, Preference, Candulor), 3D 프린팅 인공치(Dentca), 그리고 Z250 (Filtek Z250, 3M ESPE)이 실험을 위하여 준비되었다. 시편은 37℃에서 에리스로신 3% 용액, 커피, 콜라, 그리고 증류수에 침전되었다. 색 변화량(ΔE)은 침전 전, 침전 7,14,21일 후에 분광광도계로 측정되었다. Tukey's honestly significant difference 다중 비교를 이용한 일원분산분석을 시행하였다(P < .05). 결과: 대부분의 케이스에서 Dentca 인공치와 전통적인 인공치 사이의 색 변화량은 큰 차이를 보이지 않았다 (P > .05). Dentca는 에리스로신 3% 용액에 침전된 1주 뒤의 Surpass (ΔE = 0.67 ± 0.25), 2주 뒤의 Artic 6 (ΔE = 1.44 ± 0.38), Premium 6 (ΔE = 1.69 ± 0.35), 그리고 3주 뒤의 Surpass (ΔE = 1.79 ± 0.49), Artic 6 (ΔE = 2.07 ± 0.21), Premium 6 (ΔE = 2.03 ± 0.75), Preference (ΔE = 2.01 ± 0.75)와 비교했을 때 더 많은 색 변화를 보였다 (P < .05). 결론: 일부 색소에 침전된 Dentca 인공치에서 색 변화가 관찰되었으나, ΔE의 최대값은 임상적으로 받아들일 수 있는 범위 내에서 관찰되었다.

Purpose: This study evaluated color stability of Dentca 3D-printed denture teeth, in comparison to color stabilities of four conventional types of denture teeth, upon being immersed in various colorants. Materials and methods: Four types of conventional prefabricated denture teeth (Surpass, GC, Artic 6, Heraeus Kulzer, Premium 6, Heraeus Kulzer, Preference, Candulor), 3D-printed denture teeth (Dentca); and Z250 (Filtek Z250, 3M ESPE) were prepared for testing. The samples were immersed in erythrosine 3%, coffee, cola, and distilled water (DW) at 37℃. Color change (ΔE) was measured by spectrophotometer before immersion and at 7, 14, and 21 days after immersion. One-way analysis of variance was performed along with Tukey's honestly significant difference multiple comparisons test (P<.05). Results: No great difference was observed between the color change of Dentca denture teeth and that of conventional denture teeth in most cases (P>.05). The color change of Dentca denture teeth immersed in erythrosine 3% was greater than that of Surpass (ΔE = 0.67 ± 0.25) after 1 week; Artic 6 (ΔE = 1.44 ± 0.38) and Premium 6 (ΔE = 1.69 ± 0.35) after 2 weeks; and Surpass (ΔE = 1.79 ± 0.49), Artic 6 (ΔE = 2.07 ± 0.21), Premium 6 (ΔE = 2.03 ± 0.75), and Preference (ΔE = 2.01 ± 0.75) after 3 weeks (P<.05). Conclusion: A color change was observed in Dentca denture teeth when immersed in some colorants; however, the maximum value of ΔE for Dentca denture teeth was within the clinically acceptable range.

Objectives: This study aimed to evaluate the color stability of bulk-fill and nanohybrid resin-based composites polished with 3 different, multistep, aluminum-oxide impregnated finishing and polishing disks. Materials and Methods: Disk-shaped specimens (8 mm in diameter and 4 mm in thickness) were light-cured between two glass slabs using one nanohybid bulk-fill (Tetric EvoCeram, Ivoclar Vivadent), one micro-hybrid bulk-fill (Quixfil, Dentsply), and two nanohybrid incremental-fill (Filtek Ultimate, 3M ESPE; Herculite XRV Ultra, Kerr) resin-based composites, and aged by thermocycling (between $5-55^{\circ}C$, 3,000 cycles). Then, they were divided into subgroups according to the polishing procedure as SwissFlex ($Colt\grave{e}ne/Whaledent$), Optidisc (Kerr), and Praxis TDV (TDV Dental) (n = 12 per subgroup). One surface of each specimen was left unpolished. All specimens were immersed in coffee solution at $37^{\circ}C$. The color differences (${\Delta}E$) were measured after 1 and 7 days of storage using a colorimeter based on CIE Lab system. The data were analyzed by univariate ANOVA, Mann-Whitney U test, and Friedmann tests (${\alpha}=0.05$). Results: Univariate ANOVA detected significant interactions between polishing procedure and composite resin and polishing procedure and storage time (p < 0.05). Significant color changes were detected after 1 day storage in coffee solution (p < 0.05), except Quixfil/Optidisc which was color-stable after 7 days (p > 0.05). Polishing reduced the discoloration resistance of Tetric EvoCeram/SwissFlex, Tetric EvoCeram/Praxis TDV, Quixfil-SwissFlex, and all Herculite XRV Ultra groups after 7 days storage (p < 0.05). Conclusions: Discoloration resistance of bulk-fill resin-based composites can be significantly affected by the polishing procedures.

Objective: In our previous study, glass-fiber-reinforced plastics (GFRPs) made from polycarbonate and glass fibers were prepared for esthetic orthodontic wires using pultrusion. These laboratory GFRP wires are more transparent than the commercially available nickel-titanium wire; however, an investigation of the color stability of GFRP during orthodontic treatment is needed. Accordingly, in the present study, the color stability of GFRP was assessed using colorimetry. Methods: Preparation of GFRP esthetic round wires (diameter: 0.45 mm [0.018 inch]) using pultrusion was described previously. Here, to investigate how the diameter of fiber reinforcement affects color stability, GFRPs were prepared by incorporating either $13-{\mu}m$ (GFRP-13) or $7-{\mu}m$ glass (GFRP-7) fibers. The color changes of GFRPs after 24 h, and following 1, 2, and 4 weeks of coffee immersion at $37^{\circ}C$, were measured by colorimetry. We evaluated the color stability of GFRPs by two evaluating units: the color difference (${\Delta}E^*$) and National Bureau of Standards (NBS). Results: After immersion, both GFRPs showed almost no visible color change. According to the colorimetry measurements, the ${\Delta}E^*$ values of GFRP-13 and GFRP-7 were 0.73-1.16, and 0.62-1.10, respectively. In accordance with NBS units, both GFRPs showed "slight" color changes. As a result, there were no significant differences in the ${\Delta}E^*$ values or NBS units for GFRP-13 or GFRP-7. Moreover, for both GFRPs, no significant differences were observed in any of the immersion periods. Conclusions: Our findings suggest that the GFRPs will maintain high color stability during orthodontic treatment, and are an attractive prospect as esthetic orthodontic wires.

PURPOSE. The aim of this study was to compare the color stability, water sorption and cytotoxicity of thermoplastic acrylic resin for the non-metal clasp dentures to those of thermoplastic polyamide and conventional heat-polymerized denture base resins. MATERIALS AND METHODS. Three types of denture base resin, which are conventional heat-polymerized acrylic resin (Paladent 20), thermoplastic polyamide resin (Bio Tone), thermoplastic acrylic resin (Acrytone) were used as materials for this study. One hundred five specimens were fabricated. For the color stability test, specimens were immersed in the coffee and green tee for 1 and 8 weeks. Color change was measured by spectrometer. Water sorption was tested after 1 and 8 weeks immersion in the water. For the test of cytotoxicity, cell viability assay was measured and cell attachment was analyzed by FE-SEM. RESULTS. All types of denture base resin showed color changes after 1 and 8 weeks immersion. However, there was no significant difference between denture base resins. All specimens showed significant color changes in the coffee than green tee. In water sorption test, thermoplastic acrylic resin showed lower values than conventional heat-polymerized acrylic resin and thermoplastic polyamide resin. Three types of denture base showed low cytotoxicity in cell viability assay. Thermoplastic acrylic resin showed the similar cell attachment but more stable attachment than conventional heat-polymerized acrylic resin. CONCLUSION. Thermoplastic acrylic resin for the non-metal clasp denture showed acceptable color stability, water sorption and cytotoxicity. To verify the long stability in the mouth, additional in vitro studies are needed.

PURPOSE. Maxillofacial silicone elastomer is usually colored intrinsically with color pigments to match skin colors. The purpose of this study was to investigate the color stability of a maxillofacial silicone elastomer, colored with a thermochromic, color changing pigment. MATERIALS AND METHODS. Disc-shaped maxillofacial silicone specimens were prepared and divided into 3 groups: a conventionally colored control group, one group additionally colored with 0.2 wt% thermochromic pigment, and one group with 0.6 wt% thermochromic pigment. Half of the surface of each specimen was covered with an aluminium foil. All of the specimens were exposed to UV radiation in 6 hour cycles over 46 days. In between the UV exposures, half of the specimens were stored in darkness, at room temperature, and the other half was stored in an incubator, at a humidity of 97% and a temperature of $+37^{\circ}C$. Color measurements were made with a spectrophotometer and registered according to the CIELAB $L^*a^*b^*$ color model system. The changes in $L^*$, $a^*$ and $b^*$ values during artificial aging were statistically analyzed by using paired samples t-test and repeated measures ANOVA. P-values <.05 were considered as statistically significant. RESULTS. The UV exposure resulted in visually noticeable and statistically significant color changes in the $L^*$, $a^*$ and $b^*$ values in both of the test groups containing thermochromic pigment. Storage in the incubator lead to statistically significant color changes in the $a^*$ and $b^*$ values of the specimens containing thermochromic pigment, compared to those stored at room temperature. CONCLUSION. The specimens containing thermochromic pigment were very sensitive to UV radiation, and the thermochromic pigment is not suitable, as such, to be used in maxillofacial prostheses.