ABSTRACT
Objective: The objective of the present in-vitro study was to verify the efficacy of two spectrophotometer-based shade matching systems for color matching of ceramics after artificial accelerated aging (AAA). Material and Methods: The ceramics used were porcelain laminated veneers. Seventy standard-shaped discs (thickness x diameter: 0.5 mm x 10 mm) of B1 shades were used. Based upon the type of resin cement used, the specimens were divided into seven groups (10/group). The following light-cured cements were used: RelyX-Veneer (L-RV), Variolink-Veneer (L-VV), and Variolink-Esthetic (L-VE). The dual-cured cements were: RelyX Ultimate (D-RU), RelyX-Unicem (D-RC), and Variolink-Esthetics DC (D-VE). The control group consisted of ceramic only. All specimens were thermocycled in water for 3,500 cycles between 5 oC -55 oC, with dwell times of 30 s in each bath and a transfer time of 10 s between baths. All specimens were thermocycled in water for 3,500 cycles between 5 oC and 55 oC, and color measurement was done using the VITA Easyshade and ColorEye spectrophotometers. Baseline color reading was performed 24-hours after cementation. Differences in color (DE) of EasyShade and ColorEye before and after AAA were determined and compared statistically. Group comparisons were done using the paired t-tests. Level of significance was set at P< 0.05. Results: The mean differences in color (ΔE) values obtained from EasyShade spectrophotometer for light- and dual-cured cements, were 0.843±0.89 (L-RV ), 4.11±0.69 (L-VV) and 0.833±0.47 (L-VE); and 2.22±0.64 (D-RU), 3.37±0.83 (D-RC) and 0.38±0.92 (D-VE), respectively. The mean differences in color (ΔE) values obtained from ColorEye spectrophotometer for light- and dual-cured cements, were 0.68±0.86 (L-RV ), 4.55±0.83 (L-VV) and 2.68±0.26 (L-VE); and 2.06±0.84 (D-RU), 1.8±1.08 (D-RC) and 0.96±0.71 (D-VE), respectively. There was no significant difference in the mean DE values among the groups. Conclusion: The VITA Easyshade and ColorEye shade matching systems are comparable in terms of their efficacy for color matching of cerammics after AAA.(AU)
Objetivos: O objetivo do presente estudo in vitro foi verificar a eficácia de dois espectrofotômetros baseados em escalas de cor para avaliação de cor de cerâmicas após envelhecimento artificial acelerado (EAA). Material e Métodos: As cerâmicas utilizadas foram laminados cerâmicos. Foram usados setenta discos de formato padrão (0,5mm de espessura x 10 mm de diâmetro) de tonalidades B1. Com base no tipo de cimento resinoso utilizado, os corpos-de-prova foram divididos em sete grupos (10 / grupo). Foram utilizados os seguintes cimentos fotopolimerizáveis: RelyX-Veneer (L-RV), Variolink-Veneer (L-VV) e Variolink-Esthetic (L-VE). Os cimentos de cura dual foram: RelyX Ultimate (D-RU), RelyX-Unicem (D-RC) e Variolink-Esthetics DC (D-VE). O grupo controle consistia apenas de cerâmica. Todos os corpos-de-prova foram termociclados em água por 3.500 ciclos entre 5oC-55oC, com tempos de permanência de 30s em cada banho e um tempo de transferência de 10s entre os banhos. A medição da cor foi feita usando os espectrofotômetros VITA Easyshade e ColorEye. A leitura da cor inicial foi realizada 24 horas após a cimentação. As diferenças na cor (ΔE) do EasyShade e ColorEye antes e depois do EAA foram determinadas e comparadas estatisticamente. As comparações dos grupos foram feitas usando o teste t pareados. O nível de significância foi estabelecido em p <0,05. Resultados: os valores médios de diferenças na cor (ΔE) obtidos no espectrofotômetro EasyShade para cimentos fotopolimerizáveis e duais foram de 0,843 ± 0,89 (L-RV), 4,11 ± 0,69 (L-VV) e 0,833 ± 0,47 (L-VE ); e 2,22 ± 0,64 (D-RU), 3,37 ± 0,83 (D-RC) e 0,38 ± 0,92 (D-VE), respectivamente. os valores médios de diferenças na cor (ΔE) obtidos no espectrofotômetro ColorEye para cimentos fotopolimerizáveis e duais foram de 0,68 ± 0,86 (L-RV), 4,55 ± 0,83 (L-VV) e 2,68 ± 0,26 (L-VE); e 2,06 ± 0,84 (D-RU), 1,8 ± 1,08 (D-RC) e 0,96 ± 0,71 (D-VE), respectivamente. Não houve diferença significativa nos valores médios de ΔE entre os grupos. Conclusão: Os sistemas de combinação de cores VITA Easyshade e ColorEye são comparáveis em termos de eficácia para avaliação de cores de cerâmicas após EAA. (AU)
Subject(s)
In Vitro Techniques , Spectrophotometers , Dental Materials , Dental VeneersABSTRACT
Objective: To investigate the color matching of the composite resin used for repaired with initial composite resin restoration after the aging process. Material and Methods: After preparation of 30 composite resin samples, their color were determined using the spectrophotometer four times and the average was recorded. After the initial aging, the color of the samples was measured again. Then, the repair process was performed with an appropriate composite resin color for each sample and the aging process was performed again. After the second aging, the color of the initial and the repaired composite resins were measured. Then, the data were analyzed by paired T-test. The level of significance was set at 5%. Results: The color difference of the initial composite resin between before and after initial aging, as well as the color difference of repaired composite resins between before and after second aging, were significant (p<0.001). Also, after the second aging, the color difference between initial and repaired composite resin restoration were significant (p<0.001). Conclusion: The color matching of the repaired composite resin with the initial one is not acceptable. In this way, replacement of initial composite suggested instead of repaired.
Subject(s)
Tooth Bleaching/methods , Color , Composite Resins , Light-Curing of Dental Adhesives , Spectrophotometers/methods , Statistics, Nonparametric , IranABSTRACT
Objective To study the color of Ruyi Jinhuang Powder (RJP) placebo by using computer color matching technology and achieve fast preparation of RJP placebo. This work provided a new method to simulate the color of Chinese medicine compound placebo. Methods Using the RJP placebo as an example, computer color matching technology was used to establish a mathematical model to correlate the placebo color parameter L, a*, b* value and the colorant concentration. For a measured medicine compound color, the placebo colorant concentration can then be calculated from the model through data fitting and Newton iterative method. The model accuracy was validated using the color comprehensive evaluation index (ΔE). Results The color parameter L, a*, b* of RJP placebo was 68.302 5, 4.079 5, and 34.484 0. The mass fraction of lemon yellow, amaranth, and blue was 0.837 3%, 0.045 8%, and 0.008 5%. The ΔE value between RJP and its placebo was 2.750 0 ± 0.353 6, and there was no obvious visual difference between the medicine compound and its placebo. Conclusion Computer color matching technology can be used to simulate the color of RJP placebo, and can be widely used in the preparation of Chinese medicine placebo.
ABSTRACT
This study was conducted in order to assess whether the form of the shade guide affects in deciding the color of the teeth using the shade guide. Eight shade light cured composite resins (Esthet-X, Dentsply, Milford, USA) were used in this study. Shade guides including the model of maxillary central incisors, teeth-form shade guide, doughnut form shade guide, and shade guide with perforated gray shield were prepared with eight shade composite resins and provided the codes randomly. After arranging the models of teeth, 19 dentists working at the clinic of the Dentistry of Chonnam University Hospital and 65 students of college of dentistry, Chonnnam University selected the shade guides corresponding to the color of each tooth on the gray board under the D65 standard illuminant. B1 shade showed highest accuracy of about 95% among all shade guides of 3 forms applied to the test and regardless of observer, tooth form shade guide showed the highest accuracy (p < 0.05), and the doughnut form showed the lowest accuracy (p < 0.05). At the time of deciding on the color of the teeth using the shade guides as a result of above, the forms of the shade guides can affect the accuracy, and it suggests that the development of the diversified forms of shade guides, which may obtain more accurate results, is required.
Subject(s)
Humans , Composite Resins , Dentistry , Dentists , Incisor , ToothABSTRACT
Objective:To investigate the reliability of tooth color-measuring by using digital cameras.Methods: 3D-Master shade guide system was measured by Canon EOS D60,CRAIC QDI2000 micropectrophotometer and ShadeEye-NCC directly.The data collected from the three methods were analyzed statistically to evaluate the reliability of the data measured by digital cameras.Results:There was no significant difference between the data measured by digital cameras and ShadeEye-NCC statistically;while that existed between the parameters of L* collected by digital cameras and microspectrophotometer were obviously co-related(P