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1.
Braz. j. oral sci ; 21: e222812, jan.-dez. 2022. tab
Artigo em Inglês | LILACS, BBO - Odontologia | ID: biblio-1348712

RESUMO

Aim: To evaluate the influence of the parameters L* a* b* on the variation of the color of bovine tooth enamel submitted to artificial darkening, after simulated brushing, with whitening toothpastes containing blue covarine. Methods: To undertake this study in vitro, 60 specimens (SP) were divided into 6 groups (n=10): control group (CGwater) and 5 test groups (GT1-Colgate Total 12, GT2-Oral-B 3D White Perfection, GT3- Colgate Luminous Instant White, GT4-CloseUp White Diamond Attraction, GT5-Sorriso Xtreme White). The specimens were darkened with coffee and submitted to simulated brushing for 6, 12, and 24 months. The alteration in the color was evaluated using CIELAB parameters and the ΔL, Δa, Δb and ΔE were calculated. The data was analyzed through generalized linear models using the R program and considering a level of significance of 5%. Results: The parameters L*, a* and the ΔL, Δa obtained better results in the test group than in the control group. There were no statistical differences between CG and the test groups for the evaluation of the b* parameter. In the evaluation of the Δb, the GT3 differed statistically from the CG. In relation to the ΔE, all the group tests showed a variation in color statistically greater than that of the CG and the GT4 showed the greatest variation, not differing from the GT3 during the periods studied. Conclusion: The mechanical and optical whitening agents positively influenced the values L*a* and b*, as well as in its variations and in the ΔE. It is important to emphasize, however, that to analyze tooth whitening it is necessary to evaluate their parameters together


Assuntos
Dente , Cremes Dentais , Cor , Clareadores
2.
Braz. j. oral sci ; 21: e224265, jan.-dez. 2022. tab
Artigo em Inglês | LILACS, BBO - Odontologia | ID: biblio-1354719

RESUMO

Aim: This study assessed the color and translucency stability of a polymer infiltrated ceramic network (PICN) and compared it with a resin composite (RC) and a feldspathic ceramic (FEL). Methods: Disc-shaped samples of a PICN (Vita Enamic), a feldspathic ceramic (Vitablocks Mark II), and a resin composite (Brava block) were prepared from CAD/CAM blocks. PICN and RC surfaces were finished with a sequence of polishing discs and diamond paste. FEL samples received a glaze layer. The samples were subjected to 30-min immersions in red wine twice a day for 30 days. CIEL*a*b* coordinates were assessed with a spectrophotometer at baseline and after 15 and 30 days of immersion. Color alteration (ΔE00) and translucency parameter (TP00) were calculated with CIEDE2000. Average roughness was measured before the staining procedures. Color difference and translucency data were analyzed with repeated-measures ANOVA and Tukey's tests. Roughness was analyzed with the Kruskal-Wallis test. Results: Roughness was similar among the experimental groups. All materials had their color alteration significantly increased from 15 to 30 days of staining. PICN reached an intermediate ΔE00 between FEL and RC at 15 days. PICN revealed a color alteration as high as the composite after 30 days. No statistical difference was observed regarding translucency. Conclusion: PICN was not as color stable as the feldspathic ceramic at the end of the study. Its color alteration was comparable to the resin composite when exposed to red wine. However, the translucency of the tested materials was stable throughout the 30-day staining


Assuntos
Propriedades de Superfície , Teste de Materiais , Cerâmica , Desenho Assistido por Computador , Cor , Resinas Compostas
3.
Molecules ; 27(15)2022 Aug 03.
Artigo em Inglês | MEDLINE | ID: mdl-35956881

RESUMO

TiO2 films exhibiting structural colors were successfully prepared using one-step electrochemical oxidation. Results of theoretical analyses and digital simulations revealed that the structural color of a TiO2 thin film could be regulated by adjusting oxidation voltage and oxidation time with different oxidation voltages leading to changes in structural color annulus number. At a low oxidation voltage, each thin film exhibited a single structural color, while thin films with different structural colors were obtained by varying the oxidation time. By contrast, at a higher oxidation voltage, each film exhibited iridescent and circular structural color patterns associated with symmetrical decreases in surface oxidation current density along radial lines emanating from the film center to its outer edges. TiO2 films exhibiting iridescent structural colorations have broad application prospects in industrial fields related to photocatalysis and photovoltaic cells.


Assuntos
Titânio , Cor , Oxirredução , Titânio/química
4.
Biomed Res Int ; 2022: 6468281, 2022.
Artigo em Inglês | MEDLINE | ID: mdl-35958820

RESUMO

Background: The aging process can induce a change in the surface microstructure of materials, the chemical compositions of matrices, and the filler particles of resin composites. This study is aimed at evaluating the effects of accelerated artificial aging (AAA) on the color change, translucency parameter (TP), and surface hardness of resin composites. Methods: Five resin composite materials (Tetric N-Ceram, Filtek Z250, Charisma Smart, Herculite Classic, and Escom100) were evaluated. A spectrophotometer was used for color measurements (L∗, a∗, and b∗). TP and color changes (ΔE 00) were calculated using the CIEDE2000 formula. The resin materials were subjected to aging for 300 hours. The hardness and TP values were measured before and after AAA. One- and two-way ANOVA and the Tukey test were used. The significance level was accepted as p < 0.05. Results: Escom100 had significantly higher ΔE 00 values than the other resin composites, and Charisma Smart had significantly lower ΔE 00 values than the other tested materials (p < 0.05). Before and after AAA, Charisma Smart had the lowest TP values, and Filtek Z250 exhibited the highest hardness values (p < 0.05). For TP and surface hardness, the effect size value of the composite material was found to be higher than that of AAA. Conclusions: After AAA, the investigated resin composites had ΔE 00 values that were above clinically acceptable thresholds. After aging, the tested materials generally exhibited decreases in L∗ values and a∗ values, while increases in b∗ values were observed. The ΔTP values of the resin composites were similar. AAA significantly increased the surface hardness of the tested materials.


Assuntos
Resinas Compostas , Cor , Resinas Compostas/química , Dureza , Teste de Materiais , Espectrofotometria , Propriedades de Superfície
5.
Artigo em Inglês | MEDLINE | ID: mdl-35954634

RESUMO

One of the risks that we find after orthodontic treatment is the secondary appearance of white spot lesions (WLS) after the removal of fixed multi-bracket appliances. Today, there are several treatment methods, resin infiltration being the most used in the most serious cases. The objective of this study is to carry out a systematic review and meta-analysis to determine the efficacy and stability in the variables of color and gloss, six months after resin infiltration. A comprehensive search was performed in the following databases: PubMed, Embase, Google Scholar, Scopus, Medline, and Web of Science. Articles published in the last 10 years were selected, including in vivo studies with a six-month follow-up. PRISMA guidelines were followed to carry out this systematic review. All studies where the application of resin was performed on carious lesions were discarded. Once the inclusion and exclusion criteria were applied, a final sample of four articles was obtained, on which the review and meta-analysis were carried out. Once examined, all authors considered that there was an immediate improvement in both variables. However, statistically significant differences were obtained in the color change outcome, but not in the brightness outcome in the subgroup analysis after six months of icon resin infiltration.


Assuntos
Cárie Dentária , Aparelhos Ortodônticos Fixos , Cor , Cárie Dentária/terapia , Diagnóstico Bucal , Humanos , MEDLINE , PubMed
6.
Artigo em Inglês | MEDLINE | ID: mdl-35955015

RESUMO

The Food and Drug Administration (FDA) regulates artificial food colors (AFCs) in the United States. Exposure to AFCs has raised concerns about adverse behavioral effects in children. We quantified AFC exposure in women of childbearing age, pregnant women, and children and compared them to FDA and World Health Organization acceptable daily intakes (ADIs). We estimated the "typical" and "high" single-day and two-day average dietary exposure to each AFC (mg/kg/day) based on laboratory measurements and food consumption data from the 2015-2016 National Health and Nutrition Examination Survey (NHANES). We also examined whether AFC intake differed by income, education, and ethnicity. Exposure tended to be higher in children and the highest AFC exposure was found for Red No. 40. Children's mean and 95th percentile FD&C Red No. 3 estimated intakes exceeded the ADIs in some instances. Juice drinks, soft drinks, icings, and ice cream cones were major foods contributing to children's (<16 years old) AFC exposure. AFC intake was higher in participants with lower incomes and education and of African American ethnicity. The findings indicate widespread AFC exposure including in very young children. Research is needed on the sociodemographic determinants of exposure and AFC toxicokinetics to better describe the absorption and organ-specific exposure.


Assuntos
Exposição Dietética , Gestantes , Adolescente , Criança , Pré-Escolar , Cor , Dieta , Feminino , Humanos , Inquéritos Nutricionais , Gravidez , Estados Unidos , United States Food and Drug Administration
7.
BMC Oral Health ; 22(1): 321, 2022 08 01.
Artigo em Inglês | MEDLINE | ID: mdl-35915423

RESUMO

The long-term color stability and gloss retention of resin composites are among the crucial factors that affect the clinical longevity of esthetic restorations, especially in anterior teeth. This study evaluated the effect of artificial aging by immersion in different storage media and thermocycling on color and gloss of dental single-shade resin composite (Omnichroma) versus multi-shade one (Filtek Z350XT). One hundred resin-composite disc-shaped specimens were used, 50 from each group, Omnichroma and Filtek Z350XT. Ten specimens from each material acted as control group (incubated in saliva). For each material, 40 specimens were divided according to the artificial-aging protocol (immersion at 37 °C for 12 days or thermocycling for 10,000 cycles) and storage media (tea, red wine). Color and gloss were measured before and after artificial aging. Color difference (∆E00) was compared with perceptibility threshold and acceptability threshold. Data were statistically analyzed; independent t test was used to compare results between two tested materials, while two-way ANOVA was used to compare results among the different immersion media within the same material. Artificial aging (immersion or thermocycling) in tea and red wine led to significant color changes and gloss reduction in both materials (P < 0.05), in contrast to control group. Red wine produced highest color differences. Both dental resin-composites; the single-shade (Omnichroma) and multi-shade (Filtek Z350XT) displayed unacceptable discoloration and gloss reduction after artificial-aging in tea and red-wine by immersion or thermocycling simulating one-year clinical-service.


Assuntos
Resinas Compostas , Chá , Cor , Humanos , Teste de Materiais , Propriedades de Superfície
8.
Nat Mater ; 21(8): 896-902, 2022 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-35835818

RESUMO

The colour centre platform holds promise for quantum technologies, and hexagonal boron nitride has attracted attention due to the high brightness and stability, optically addressable spin states and wide wavelength coverage discovered in its emitters. However, its application is hindered by the typically random defect distribution and complex mesoscopic environment. Here, employing cathodoluminescence, we demonstrate on-demand activation and control of colour centre emission at the twisted interface of two hexagonal boron nitride flakes. Further, we show that colour centre emission brightness can be enhanced by two orders of magnitude by tuning the twist angle. Additionally, by applying an external voltage, nearly 100% brightness modulation is achieved. Our ab initio GW and GW plus Bethe-Salpeter equation calculations suggest that the emission is correlated to nitrogen vacancies and that a twist-induced moiré potential facilitates electron-hole recombination. This mechanism is further exploited to draw nanoscale colour centre patterns using electron beams.


Assuntos
Compostos de Boro , Cor
9.
J Evol Biol ; 35(8): 1110-1125, 2022 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-35830483

RESUMO

Although snails of the genus Cepaea have historically been important in studying colour polymorphism, an ongoing issue is that there is a lack of knowledge of the underlying genetics of the polymorphism, as well as an absence of genomic data to put findings in context. We, therefore, used phylogenomic methods to begin to investigate the post-glacial history of Cepaea nemoralis, with a long-term aim to understand the roles that selection and drift have in determining both European-wide and local patterns of colour polymorphism. By combining prior and new mitochondrial DNA data from over 1500 individuals with ddRAD genomic data from representative individuals across Europe, we show that patterns of differentiation are primarily due to multiple deeply diverged populations of snails. Minimally, there is a widespread Central European population and additional diverged groups in Northern Spain, the Pyrenees, as well as likely Italy and South Eastern Europe. The genomic analysis showed that the present-day snails in Ireland and possibly some other locations are likely descendants of admixture between snails from the Pyrenees and the Central European group, an observation that is consistent with prior inferences from mitochondrial DNA alone. The interpretation is that C. nemoralis may have arrived in Ireland via long-distance migration from the Pyrenean region, subsequently admixing with arrivals from elsewhere. This work, therefore, provides a baseline expectation for future studies on the genetics of the colour polymorphism, as well as providing a comparator for similar species.


Assuntos
DNA Mitocondrial , Gastrópodes , Animais , Cor , DNA Mitocondrial/genética , Humanos , Filogenia , Polimorfismo Genético
10.
São Paulo; s.n; 20220720. 105 p.
Tese em Português | LILACS, BBO - Odontologia | ID: biblio-1379535

RESUMO

O intuito do presente estudo foi avaliar o efeito de laminados cerâmicos de dissilicato de lítio e cimentos resinosos com cor para mascarar diferentes substratos e a compatibilidade de cor das pastas try-in. Foram produzidos 120 laminados cerâmicos de dissilicato de lítio na cor B1 com 0,5 mm de espessura em três diferentes níveis de translucidez: HT, MT e LT (Emax CAD Ivoclar); cimentados com cimento resinoso (Allcem Veneer FGM) nas cores Opaque White (OW) e Trans (TRANS), com espessura de cimentação de 100 micrômetros, em substratos de resina composta (Opallis FGM) de 3mm (1mm esmalte e 2mm dentina), com saturações opostas: A1 e A4, totalizando 12 grupos (n=10). Os espécimes foram submetidos à análise de cor por meio de um espectrofotômetro e as leituras feitas em oito diferentes tipos: laminados, substratos, prova seca, prova úmida, try-in, cimento resinoso não polimerizado, polimerizado imediato (T0) e polimerizado após 24 horas (T24). A partir dessas leituras foram obtidos os valores L*, a* e b* de reflectância, calculada a diferença de cor (E00) e o parâmetro de translucidez (PT). Para interpretação foram utilizados limites de perceptibilidade (LP) e aceitabilidade (LA) de diferença de cor sendo E00 = 0.8 o LP e E00 = 1.8 o LA. As diferenças de cores entre a pasta try-in e o cimento polimerizado em T0 e T24; e do cimento resinoso polimerizado imediato (T0) e após 24 horas (T24) mantiveram abaixo do LA e analisadas pelo teste de Kruskal Wallis não foram encontradas diferenças estatisticamente significativas (p>0.05). Os valores de E00 obtidos entre as cores de cimento resinoso nas cerâmicas HT e MT mantiveram acima do LA e nas LT abaixo do LA e acima do LP, e analisados por ANOVA não foram encontradas diferenças entre eles (p>0.05). Na comparação de cor entre os substratos (A1 e A4) os valores de E00 mantiveram acima do LA, com uma menor diferença na cerâmica LT, comprovada pelo teste de Kruskal Wallis (p=0.000) e Dunn. Para os valores de E00 obtidos da diferença entre a prova úmida com a cor final da restauração, foi realizado teste de Kruskall Wallis e Dunn, que identificaram diferenças (p=0.0001) entre HTTRANS e HTOW em T0, HTOW em T0 com todos os grupos de LT e HTOW em T24 e LTTRANS e LTOW em T0 no substrato de cor A1 e diferenças entre os grupos (p=0.000) HTOW em T0 e T24 e LTOW em T0 no substrato de cor A4. No parâmetro de translucidez (PT) foi realizado o teste de Mann-Whitney. Para o substrato A1, existiu diferença entre os grupos (p=0.0028) onde HT-TRANS se apresenta com maior translucidez, e no substrato A4 o teste não apontou diferença entre os grupos (p>0.05). Pode-se concluir que as cores das pastas try-in são fiéis aos seus cimentos polimerizados e que existe estabilidade de cor da restauração nas primeiras 24 horas. A cor do substrato é a principal variável na translucidez da restauração com laminados ultrafinos e a translucidez da cerâmica é o fator chave na capacidade de mascaramento de diferentes cores de substratos.


Assuntos
Substratos para Tratamento Biológico , Cor
11.
São Paulo; s.n; 20220720. 110 p.
Tese em Português | LILACS, BBO - Odontologia | ID: biblio-1379734

RESUMO

Este estudo tem como objetivo avaliar a influência de um gel clareador de peróxido de carbamida à 16% (Whiteness Perfect, FGM, Joinville, SC, Brasil) associados a biomateriais (Biosilicato® ou biovidro F18®), na alteração de cor e microdureza do esmalte e dentina de dentes bovinos. Um espectrofotômetro odontológico (VITA Easyshade Compact, Vident, Brea, CA, USA) foi utilizado para obter as coordenadas de cor (L*, a*, b*), e diferença de cor foi avaliada através do sistema CIELAB (Eab), CIEDE2000 (E00) e índice de clareamento (WID). Foram selecionados123 dentes bovinos, cor A2 e seccionados usando uma máquina de corte (Isomet 1000, Buehler Ltd, Lake Bluff, IL, EUA). foram seccionados transversalmente 63 desses dentes, com uma porção de esmalte e dentina, para o teste de microdureza (microdureza Knoop), com espessura de 4mm, e divididos, por sorteio, em 3 grupos (n=21); 60 dentes foram preparados para a avaliação da mudança de cor (métodos CIELAB, CIEDE2000 e WID), cortados em fragmentos de 7mm X 7mm X 4mm, e divididos, por sorteio, em 3 grupos (n=20). Todos os fragmentos foram embutidos em tubos de PVC (policloreto de vinila) com auxílio de resina acrílica quimicamente ativada (Jet, Artigos Odontológicos Clássico Ltda, Brasil) resultando em corpos de prova de 15mm de altura e 20mm de diâmetro. Tanto o teste de microdureza quanto as medições de cor foram realizados incialmente. Para o grupo controle, os espécimes receberam tratamento clareador com gel clareador de peróxido de carbamida 16%; para o grupo Biosilicato, os espécimes receberam o tratamento clareador associado ao Biosilicato® a 2%; e para o grupo F18®, os espécimes receberam tratamento clareador associado ao biovidro F18 a 2%. O gel foi aplicado na superfície na quantidade de 0,06 gramas no grupo controle e 0,06 gramas mais 2% de material bioativo para os outros dois grupos, pesados com balança analítica de precisão (Adventurer Pro Analytical Balance 260g, Ohaus Corporation, New Jersey, EUA). O gel foi aplicado diariamente, por 8 horas, durante 14 dias consecutivos, conforme orientação do fabricante. Diariamente, ao final do tempo de aplicação, o gel era removido e os espécimes eram imersos em saliva artificial e armazenados a 37°C. Após o tratamento clareador, foram realizadas novas medidas de microdureza e cor. Os resultados de microdureza Knoop em esmalte e dentina, coordenadas de cor (L*, a*, b*) e o índice de clareamento inicial e final (WID inicial e final) foram submetidos à ANOVA de medidas repetidas de dois fatores, seguida do teste de Tukey para contraste de média (= 0,05). As medidas de diferença de cor de Eab, E00 e variação do índice de clareamento (WID) foram submetidas a ANOVA de medidas repetidas de um fator. Para o grupo controle houve redução estatisticamente significativa nos valores de microdureza do esmalte após o tratamento clareador (p<0,05). Os grupos Biosilicato® e F18® tiveram aumento estatisticamente significativo na microdureza Knoop (p<0,05), quando comparados aos seus valores antes do tratamento. Em relação à dentina, houve, no grupo controle, redução estatisticamente significativa da microdureza após o tratamento clareador (p<0,05), o que também foi observado para os grupos associados ao Biosilicato® e F18®. O grupo de tratamento associado ao Biosilicato® obteve a menor diminuição no valor de microdureza Knoop em dentina, seguido do tratamento associado ao F18®. O grupo controle, por outro lado, teve a maior diminuição da microdureza, sendo estatisticamente diferente dos demais (p<0,05). Em relação aos parâmetros de luminosidade (L*), a* e b*, todos os grupos tiveram aumento estatisticamente significante no valor quando comparados aos valores iniciais (p<0,05). Quanto à diferença de cor, os três grupos apresentaram Eab sem diferença estatisticamente significante entre eles (p>0,05). Em relação ao índice de clareamento, após o tratamento clareador, os três grupos tiveram aumento significativo do WID, que foi estatisticamente diferente dos valores iniciais (p<0,05). Ao comparar o fator grupo, os três tipos de tratamento não apresentaram diferença estatisticamente significante no WID final (p>0,05). Diante disso, o uso de materiais bioativos associados a um agente clareador reduz os efeitos negativos do tratamento, sem diminuir sua eficácia clareadora


Assuntos
Clareamento Dental , Cor
12.
Am J Dent ; 35(2): 133-136, 2022 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-35798707

RESUMO

PURPOSE: To evaluate the whitening efficacy of charcoal powder compared to a whitening toothpaste and the surface loss using scanning electron microscopy (SEM) and confocal laser scanning microscope (CLSM). METHODS: 60 human extracted teeth were randomly assigned to two groups: Treatment (T, charcoal group: Premium Nature) and Control (C, whitening toothpaste group: Colgate Optic White). Teeth in the treatment group were brushed with a charcoal paste. Teeth shade was evaluated before and after the intervention. Lightness was assessed using both VITA classical shade guide and VITA Easyshade V. Changes within and between the group were evaluated by the paired-sample t-test and independent sample t-test. Surface roughness (Ra) of samples was performed using SEM, and to assess surface loss a CLSM was used. RESULTS: At baseline, there were no significant differences in teeth lightness, chroma, or hue between both the charcoal and the whitening toothpaste groups (P> 0.05). After 21 days of brushing, teeth brushed with the whitening toothpaste were significantly lighter (VITA Easyshade mean score: 78.34, SD: 8.397; VITA classical A1-D4 shade mean: 8.90, SD: 4.475) than the charcoal group (VITA Easyshade mean: 69.70, SD: 6.364; VITA classical A1-D4 shade mean: 11.77; SD: 3.421) (P< 0.001). In addition, there was a significant reduction in lightness (i.e., increase in darkness) within the charcoal group after the intervention (P< 0.001). There was no significant difference in chroma and hue between the charcoal and the whitening toothpaste groups (P> 0.05). There was no significant tooth loss nor roughness change (P= 0.867) for both groups when compared with natural tooth structure. Brushing teeth with the charcoal paste tested for 21 days had no effect on tooth lightness, chroma, or hue. Charcoal powder had no significant effect on tooth surface roughness. CLINICAL SIGNIFICANCE: The Premium Nature charcoal toothpaste tested had no tooth whitening effect.


Assuntos
Clareamento Dental , Cremes Dentais , Carvão Vegetal/uso terapêutico , Cor , Esmalte Dentário , Humanos , Pós , Cremes Dentais/química , Cremes Dentais/farmacologia , Cremes Dentais/uso terapêutico
13.
Am J Dent ; 35(2): 141-145, 2022 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-35798709

RESUMO

PURPOSE: To evaluate the degree of stain absorption of resin composite following different finishing and polishing protocols and to evaluate the efficacy of prophylaxis paste with or without addition of carbamide peroxide to remove composite surface stain. METHODS: 50 resin composite blocks were prepared using nano-hybrid composite (Filtek Z250XT) and giomer (Beautifil II LS). Specimens were either polished with a disk or coated with 5th/7th generation bonding or glycerin gel. The color parameters (lightness, chroma and hue) of the specimens were measured prior to staining, and after 1 and 2 weeks of staining using a color chromometer. The composite surface stain removal capability of prophylaxis pastes with or without the addition of carbamide peroxide was evaluated before and after polishing. RESULTS: The repeated measures ANOVA showed that composite polished with a polishing disk or coated with glycerin gel have better color stability compared to composite without any polishing or coated with 5th or 7th generation bonding materials. The prophylaxis paste was able to remove composite surface stain; however, the addition of carbamide peroxide did not show any additional benefit. The results suggested that polishing with polishing disks or coating with glycerin gel is useful for the color stability of resin composite. CLINICAL SIGNIFICANCE: Selection of finishing and polishing protocols varies among individual practitioners. Each of these protocols has some pros and cons concerning the esthetic and color stability of composite. The present results suggested that the use of polishing disk or glycerin gel during polymerization would be a useful protocol to achieve and maintain esthetically stable composite restorations.


Assuntos
Corantes , Polimento Dentário , Peróxido de Carbamida , Cor , Resinas Compostas , Materiais Dentários , Polimento Dentário/métodos , Glicerol , Teste de Materiais , Propriedades de Superfície
14.
Sensors (Basel) ; 22(14)2022 Jul 20.
Artigo em Inglês | MEDLINE | ID: mdl-35891097

RESUMO

The appearance characteristics of ceramic color are an important factor in determining the user's aesthetic perception of the product. Given the problem that ceramic color varies and the user's visual sensory evaluation of color is highly subjective and uncertain, a method of quantifying ceramic color characteristics based on the Back Propagation (BP) neural network algorithm is proposed. The semantic difference method and statistical method were used to obtain quantified data from ceramic color perceptual semantic features and were combined with a neural network to study the association between ceramic color features and user perceptual-cognitive evaluation. A BP neural network was used to build a ceramic color perceptual semantic mapping model, using color semantic quantified values as the input layer, color L, A, and B component values as the output layer, and model training to predict the sample. The output color L, A, and B components are used as the input layer and the color scheme was designed. The above method can effectively solve the mapping problem between the appearance characteristics of ceramic color and perceptual semantics and provide a decision basis for ceramic product color design. The case application of color design of daily-use ceramic products was conducted to verify the effectiveness and feasibility of the quantitative research method of ceramic color imagery.


Assuntos
Redes Neurais de Computação , Semântica , Cerâmica , Cor
15.
Nat Commun ; 13(1): 4044, 2022 Jul 13.
Artigo em Inglês | MEDLINE | ID: mdl-35831308

RESUMO

Structural colors have a demonstrated value in constructing various functional materials. Efforts in this area are devoted to developing stratagem for generating heterogeneous structurally colored materials with new architectures and functions. Here, inspired by icing process in nature and ice-templating technologies, we present freeze-derived heterogeneous structural color hydrogels with multiscale structural and functional features. We find that the space-occupying effect of ice crystals is helpful for tuning the distance of non-close-packed colloidal crystal nanoparticles, resulting in corresponding reflection wavelength shifts in the icing area. Thus, by effectively controlling the growth of ice crystals and photo-polymerizing them, structural color hydrogels with the desired structures and morphologies can be customized. Other than traditional monochromatic structure color hydrogels, the resultant hydrogels can be imparted with heterogeneous structured multi-compartment body and multi-color with designed patterns through varying the freezing area design. Based on these features, we have also explored the potential value of these heterotypic structural color hydrogels for information encryptions and decryptions by creating spatiotemporally controlled icing areas. We believe that these inverse ice-template structural color hydrogels will offer new routes for the construction and modulation of next generation smart materials with desired complex architectures.


Assuntos
Gelo , Nanopartículas , Cor , Excipientes , Congelamento , Hidrogéis/química
16.
Molecules ; 27(13)2022 Jun 21.
Artigo em Inglês | MEDLINE | ID: mdl-35807218

RESUMO

In this study, beef mince (approximately 4% fat longissmus costarum muscle of approximately 2-year-old Holstein cattle) was used as a material. High-pressure processing (HPP) was applied to frozen and unfrozen, vacuum-packed minced meat samples. The pH and thiobarbituric acid (TBA) values of the samples were examined during 45 days of storage. Color values (L*, a* and b*) and texture properties were examined during 30 days of storage. After freezing and HPP (350 MPa, 10 min, 10 °C), the pH value of minced meat increased (p > 0.05) and its TBA value decreased (p < 0.05). The increase in pH may be due to increased ionization during HPP. Some meat peptides, which are considered antioxidant compounds, increased the oxidative stability of meat, so a decrease in TBA may have been observed after freezing and HPP. While the color change in unpressurized samples was a maximum of 3.28 units during storage, in the pressurized sample, it exceeded the limit of 10 units on the first day of storage and exceeded the limit of 10 units on the third day of storage in the frozen and pressurized sample. Freezing and HPP caused the color of beef mince to be retained longer. The hardness, gumminess, chewability, adherence, elasticity, flexibility values of the pressurized and pressurized after freezing samples were higher than those of the unpressurized samples during storage. On the other hand, the opposite was the case for the adhesiveness values. In industrial applications, meat must be pressurized after being vacuum packed. If HPP is applied to frozen beef mince, some of its properties such as TBA, color, and texture can be preserved for a longer period of time without extreme change.


Assuntos
Carne , Animais , Bovinos , Cor , Congelamento , Concentração de Íons de Hidrogênio , Carne/análise , Tiobarbitúricos , Vácuo
17.
Sci Rep ; 12(1): 12194, 2022 Jul 16.
Artigo em Inglês | MEDLINE | ID: mdl-35842462

RESUMO

Facial colour characteristics convey vital personal information and influence social interactions and mate choices as contributing factors to perceived beauty, health, and age. How various colour characteristics affect facial preference and whether there are cultural differences are not fully understood. Here, we provide a useful and repeatable methodology for skin colour research based on a realistic skin model to investigate the effect of various facial colour characteristics on facial preference and compare the role of colour predictors in Caucasian (CA) and Chinese (CN) samples. Our results show that, although the average skin colour of facial areas plays a limited role, together with colour variation and contrast, there are stronger links between colour and facial preference than previously revealed. We also find large cultural differences in facial colour perceptions; Chinese observers tend to rely more heavily on colour and lightness cues to judge facial preference than Caucasian observers.


Assuntos
Beleza , Face , China , Cor , Humanos , Brancos
18.
J Environ Public Health ; 2022: 8303496, 2022.
Artigo em Inglês | MEDLINE | ID: mdl-35774189

RESUMO

This work was conducted to study the Chinese painting color teaching analysis of intelligent image color processing technology under the network environment. First, the paper preprocesses the obtained color mural images, realizes the automatic recognition and marking of the images with different defect degrees and color fading, and uses denoising and texture background elimination to remove unnecessary background information. Then, according to the characteristic that the repair order of boundary points in the Criminisi algorithm is determined by the size of priority weight, the data items and confidence items are added. Finally, the design uses image processing technology and the loss formula to identify the connecting edge of the color area to be taught, establish the color extraction area, calculate the bit weight of the best color, find out the color extraction position, and synthesize different colors according to the original painting color superposition method. The partial differential equation is used to set the teaching code of color teaching system to realize the teaching of Chinese painting color. The experimental results show that compared with the original teaching system, the designed color teaching system has a stronger ability to recognize the edge of Chinese painting color teaching, and the quality of Chinese painting after teaching is higher. It can be seen that the color teaching system can be applied to the color teaching of Chinese painting.


Assuntos
Processamento de Imagem Assistida por Computador , Pinturas , China , Cor , Processamento de Imagem Assistida por Computador/métodos , Tecnologia
19.
Sci Rep ; 12(1): 11140, 2022 Jul 01.
Artigo em Inglês | MEDLINE | ID: mdl-35778454

RESUMO

Red-green colour vision deficiency (CVD) affects ~ 4% of Caucasians. Notch filters exist to simulate CVD when worn by colour vision normal (CVN) observers (simulation tools), or to improve colour discrimination when worn by CVD observers (compensation tools). The current study assesses effects of simulation (Variantor) and compensation (EnChroma) filters on performance in a variety of tasks. Experiments were conducted on 20 CVN and 16 CVD participants under no-filter and filter conditions (5 CVN used Variantor; 15 CVN and 16 CVD used EnChroma). Participants were tested on Ishihara and Farnsworth-Munsell 100 hue tests, CVA-UMinho colour discrimination and colour naming tasks and a board-game colour-sorting task. Repeated-measures ANOVAs found Variantor filters to significantly worsen CVN performance, mimicking protanopia. Mixed-model and repeated-measures ANOVAs demonstrate that EnChroma filters do not significantly enhance performance in CVD observers. Key EnChroma results were replicated in 8 CVD children (Ishihara test) and a sub-sample of 6 CVD adults (CVA-UMinho colour discrimination and colour naming tasks) for a smaller stimulus size. Pattern similarity exists across hue for discrimination thresholds and naming errors. Variantor filters are effective at mimicking congenital colour vision defects in CVN observers for all tasks, however EnChroma filters do not significantly compensate for CVD in any.


Assuntos
Doenças Cardiovasculares , Defeitos da Visão Cromática , Visão de Cores , Adulto , Criança , Cor , Testes de Percepção de Cores/métodos , Defeitos da Visão Cromática/diagnóstico , Humanos
20.
J Indian Soc Pedod Prev Dent ; 40(2): 159-164, 2022.
Artigo em Inglês | MEDLINE | ID: mdl-35859408

RESUMO

Background: Strip crowns are the first treatment of choice for restoring anterior teeth affected with early childhood caries. However, shade matching of resin composites is still an issue. The broad color matching ability of a recently introduced single shade composite, Omnichroma eliminates the need for shade-matching procedure, reduces composite inventory, and minimizes chair-side time. Aim: The aim is to evaluate the color match, color stability, and retention of one shade universal composite resin, Omnichroma and nanohybrid resin composite, Tetric-N-Ceram. Design: The study design involves split-mouth randomized controlled trial. Methods: The study was conducted on 25 children aged 3-5 years with multi-surface caries lesions in primary maxillary anterior teeth. Teeth were allocated to two groups randomly: Group 1 - One shade universal composite, Omnichroma (n = 25), Group 2 - Nanohybrid composite, Tetric-N-Ceram (n = 25). After caries excavation and tooth preparation, teeth were restored with corresponding materials using strip crowns. Color match at baseline, color stability, and retention after 6- and 12-month follow-up were evaluated using the Modified United States Public Health Services criteria. Analysis: The Mann-Whitney U test and Wilcoxon signed-rank test were used to analyze the data. Results: On comparison of Omnichroma and Tetric-N-Ceram groups, no statistically significant difference was observed in the color match at baseline (P = 0.716) as well as color stability (P = 0.575 at 6 months and 0.990 at 12 months) and retention (P = 0.153 at 6 months and 0.226 at 12 months) at both 6- and 12-month intervals. On intragroup comparison, the difference in the color stability at 6 and 12-month interval was statistically significant (P = 0.001) for both the groups, indicating that the color stability of restorations was better at 6-month interval compared to 12-month interval. In both Omnichroma and Tetric-N-Ceram groups, retention of restorations was better at 6-month interval compared to 12-month interval and this difference was statistically significant (P = 0.025 and 0.014, respectively). Conclusion: The clinical performance of Omnichroma in terms of color match, color stability, and retention was comparable to nanohybrid composite, Tetric-N-Ceram.


Assuntos
Cárie Dentária , Incisivo , Criança , Pré-Escolar , Cor , Resinas Compostas/uso terapêutico , Cárie Dentária/terapia , Restauração Dentária Permanente/métodos , Estética Dentária , Humanos , Estados Unidos
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