ABSTRACT
This study aims to explore the change laws of water absorption in Chinese herbal pieces and establish the prediction model of relative density for Chinese medicine compound decoction. Firstly, fitted equations of water absorption and decocting time was established by observing the change laws of water absorption in 36 kinds of Chinese herbal pieces in 12 groups(according to the drug-parts) with decocting time. The r value of the mineral group and other type group was 0.691 2 and 0.663 3, respectively. The r value of the remaining 10 groups was 0.802 2-0.925 4. All P values were less than 0.05(n=21). The formula of the amount of water added was optimized by combining the fitted equations with determined water absorption, and the liquid yield could be controlled in a range of 100%±10%. Secondly, it was determined that the liquid density tester could be used for the rapid determination of relative density of Chinese medicine decoction after methodological study and comparison with the pycnometer method. The linear regression equation between the corrected relative density(y) and extraction ratio(%, x) was built by measuring and analyzing the related parameters such as liquid yield, relative density and extraction ratio in 46 kinds of Chinese herbal pieces. The established equation was y=0.041 3x+1.003 7, r=0.930 9(P <0.01, n=46), with linear range of 1.94%-65.75%. Based on this, the prototype model for predicting relative density of Chinese medicine decoction was established, and the relative densities of 8 Chinese medicine decoctions were within the prediction interval of this model in verification. This study lays a foundation for database construction of Chinese medicine decoction, implementation of personalized decocting mode and rapid quality control of Chinese medicine decoction.
Subject(s)
Drugs, Chinese Herbal , Medicine, Chinese Traditional , Quality Control , Specific Gravity , WaterABSTRACT
Abstract Sweet orange juice is an important part of diet since it is nutritious beverage offering good taste and play significant part in a healthy diet. High hygroscopicity, thermo-plasticity and presence of low molecular weight components in sweet orange juice offer low glass transition temperature (Tg), likely to form soft particle with sticky surface leading to sticky powder during drying. Maltodextrins are amorphous drying aids that tend to inhibit sugar crystallization and form a high Tg product after drying. In this study, the effect of the different spray drying parameters on the quality of powder derived from control and concentrated juice at three inlet air temperatures 120, 130 and 140 °C and at three levels of juice total soluble solids (TSS): maltodextrin levels at 1:0.5; 1:1 and 1:1.5 were studied. The impact of inlet air temperature and maltodextrin concentration has significantly affected various properties of sweet orange powder. For control juice, process yields increased with increase in inlet air temperature and maltodextrin concentration. However, for reverse osmosis (RO) concentrate, process yield increased with increase in maltodextrin concentration and decreased with increase in inlet air temperature. For control juice, process yields obtained were in the range of 12.59-41.16% and in case of concentrated juice, the process yield obtained was in the range of 21.35-56.95% at different combinations of inlet air temperature and maltodextrin concentrations. Spray-dried powder was considered as "possible" and "fair" in terms of flowability and cohesiveness. Vitamin C retention was high at lower inlet air temperature with lower concentration of maltodextrin.
Subject(s)
Polysaccharides/pharmacology , Temperature , Food Production , Citrus sinensis , Fruit and Vegetable Juices/analysisABSTRACT
ABSTRACT Amaranth flour is of high nutritional value, which makes it a potential food. Grinding of the grains is a necessary operation to obtain products with physical properties that provide the food products with adequate characteristics. To analyze the effect of grinding velocity and time on the particle diameters and physical properties of Amaranth flour by ball mill, a Doehlert design with triplicate at the central point was used. The tests were carried out with the mass ratio (balls/samples) (R1:5). Granulometry curve of each design system was fitted to the Rosin-Ramler-Bennet and Holmes-Hukki equations. A found a very significant effect of the velocity on the particle diameters (D50, D63 and D80). The flour obtained were modeled satisfactorily (r2>0.99) by using the Rosin-Ramler-Bennet equation, where the homogeneity index of (n1) was obtained, which was directly influenced by the milling energy. By using the Holmes-Hukki model, were able to model the characteristic diameters with the grinding energy; a critical region was observed between 100μm and 200μm, where lost efficiency in the size reduction. The excess energy, released in the critical region, caused the decrease in starch crystallinity and structural changes in the protein, which affect the functional properties of the flour. The planetary mill is emerging as an effective mean of modifying the functional properties in the development of new food products.
RESUMEN La harina de amaranto es de alto valor nutricional, convirtiéndola en un alimento potencial. La molienda de los granos es una operación necesaria, para brindarle a los productos alimenticios unas adecuadas propiedades físicas. Para analizar el efecto de la velocidad y el tiempo de molienda sobre el diámetro de particular y las propiedades físicas de la harina obtenida por molienda de bolas, se usó un diseño experimental Doehlert, con réplica en el punto central. En las pruebas de molinería se tuvo en cuenta la relación masa de bolas/masa de muestra (R1:5). Las curvas de granulometría de cada punto del diseño experimental fueron modeladas por las ecuaciones de Rosin-Ramler-Bennet y Holmes-Hukki. Se encontró un efecto muy significativo de la velocidad de molienda sobre los diámetros característicos (D50, D63 y D80). El modelo de Rosin-Ramler-Bennet ajustó satisfactoriamente (r2>0.99), además, se obtuvo el índice de homogeneidad (n1), el cual, fue afectado directamente por la energía de molienda. El uso del modelo de Holmes-Hukki permitió relacionar el diámetro de partícula con la energía de molienda y se logró observar una región crítica entre 100μm y 200μm, donde hay una reducción en la eficiencia de la reducción de tamaño de partícula. El exceso de energía liberada en la región crítica causó el descenso en la cristalinidad del almidón y provocó cambios en la estructura de las proteínas, lo cual, modificó las propiedades físicas de la harina. El Molino planetario es una técnica emergente y efectiva para modificar las propiedades funcionales en el desarrollo de nuevo productos alimenticios.
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Objective To determine the water absorption coefficient of single-flavor root and rhizome Chinese herbal medicine pieces at room temperature, and guide the water addition in the decoction process of decocting machine of Chinese herbal.Methods The water absorption coefficient of 222-flavor root and rhizome Chinese herbal medicine pieces were studied, the simulated prescriptions were decocted according to the recommended formula of the decocting machine manufacturer and the water absorption coefficient, and the amount of liquid were obtained by the two methods which were compared with the amount of liquid required.Results The water absorption coefficients of roots and rhizomes with different textures were quite different.The amount of liquid obtained according to the manufacturer′s recommended formula was quite different from the amount of liquid required and there was no rule to follow.The error of the amount of liquid obtained according to the water absorption coefficient and the amount of liquid required was small and regular.Conclusion The experimental determination of the water absorption coefficient of traditional Chinese medicine decoction pieces could guide the amount of water added to the decoction machine.
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Objective@#To evaluate water sorption and hygroscopic dimensional changes of five core buildup composite resins, and to provide references for material modification on water sorption.@*Methods@#Five commercial core buildup materials (group A: Smart Dentin ReplacementTM; group B: NanoFil; group C: ParaCoreTM; group D: LuxaCore Z; group E: EmbraceCoreTM Resin Cement) were fabricated to disk-shaped specimens: (15.0±0.1) mm diameter, (2.0±0.1) mm thickness (n=10). Specimens were thoroughly irradiated with curing lights. The initial mass in air was recorded, and the initial mass in deionized water was recorded. Five specimens of each group were immersed in deionized water for 28 d. They were weighed as a function of different immersion time (1, 2, 3, 4, 5, 6, 7, 14, 28 d). The mass in air was recorded, and the displayed mass in deionized water was recorded. Archimedes' principle was applied to calculate the dimensional changes. The other five specimens of each group were stored in artificial saliva and were tested by the same methods.@*Results@#All specimens gained weight and hygroscopic changes during 28 d immersion. When stored in deionized water, the apparent mass change of group A [(10.6±0.9) μg/mm3] and the dimensional change of group A [(0.39±0.10)%] were the lowest, while the mass change of group E [(48.0±0.2) μg/mm3] and the dimensional change of group E [(3.16±0.13)%] were the highest (P<0.05). In artificial saliva, the lowest apparent mass change was found in group A [(11.8±1.0) μg/mm3] while the highest change was found in group E [(47.4±3.5) μg/mm3] (P<0.05). The lowest dimensional change was found in group C [(0.37±0.09)%] and the highest was found in group E [(3.07±0.19)%] in artificial saliva (P<0.05).@*Conclusions@#Water sorption and dimensional changes vary in immersion fluids with different osmotic pressure. Water sorption and dimensional changes of core buildup composite resins are highly correlated with test materials in both of the deionized water and artificial saliva.
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Objective: To study the effects of different pretreatment methods and culture temperatures on Seed Germination and seedling growth of Bupleurum chinense, in order to provide scientific basis for artificial cultivation of B. chinense. Methods: Several physiological indexes such as the weight, pure rate, content of moisture, the rate of water absorption per thousand seeds were measured. Adopting a double-layer filter paper culture method, the pretreated seeds were cultured in the incubator at 20 ℃ in the 40% light. In different culture temperature treatment groups, the seeds were soaked in distilled water 24 h and then cultured in the corresponding temperature incubator. The germination energy, germination percentage, germination index, vigor index of seeds, and the root length and the shoot height of the seedling were recorded. Results: The pure rate of seeds was 91.51%, the weight of one thousand seeds was (2.83 ± 0.03) g and the weight of seed after absorbing water was about 2.24 times more than the weight of naturally dried seed. The content of moisture of seeds was 7.3%. Different hormones had different effects on seeds, among them the effect of 0.6 mg/L 6-BA treatment was the best. Water bath could increase the seedling vigor index, and 40 ℃ of its temperature significantly promoted the seed germination and seedling growth. The germination rate of seeds was the highest under the condition of 15 ℃, but the root length and seedling height were lower. Conclusion: The suitable condition for seed pretreatment and culture temperature of B. chinense established in this research can effectively improve the germination rate and seedling rate, which is of great significance for seed breeding and artificial cultivation of B. chinense.
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ABSTRACT: The current research aimed to evaluate the effects of extrusion parameters on the physical characteristics of extruded blends of cassava leaf flour and starch. A factorial central composite design with four independent variables and the response surface methodology were used to evaluate the results of color parameters (L*, a*, b*), water absorption index, water solubility index and paste properties, according to the variations in the leaf flour percentage (1.5 to 7.5%), extrusion temperature (60 to 100ºC), screw speed (175 to 231rpm) and moisture (20 to 30%). Extrusion conditions affect color, water absorption and water solubility indexes and paste properties of blends. The intermediate tested conditions of variable parameters lead to obtain extruded products with higher cold viscosity and water absorption index and light color, desirable qualities for rapid preparation products.
RESUMO: Este trabalho teve por objetivo avaliar os efeitos dos parâmetros de extrusão sobre as características físicas de misturas extrusadas de farinha de folhas de mandioca e amido. O delineamento central composto rotacional, com quatro variáveis independentes, e a metodologia de superfície de resposta foram utilizados para avaliar os resultados dos parâmetros de cor (L*, a*, b*), índice de absorção de água, índice de solubilidade em água e propriedades de pasta, de acordo com as variações da percentagem de farinha de folha (1,5 a 7,5%), da temperatura de extrusão (60 a 100ºC), da rotação da rosca (175-231rpm) e da umidade (20 a 30%). As condições do processo de extrusão afetaram a cor, os índices de absorção de água e solubilidade em água e as propriedades de pasta das misturas. As intermediárias testadas dos parâmetros variáveis levaram à obtenção de produtos extrusados com maior viscosidade fria e índice de absorção de água e de cor clara, qualidades desejáveis para produtos de preparação rápida.
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Objective: The purpose of this paper is to verify the key role of water absorption in the process of disintegration of Chinese materia medica (CMM) dispersible tablets, so as to provide the solution idea for slow disintegration of CMM dispersible tablets. Methods: In this paper, the influence of water absorption of raw materials and auxiliary materials on disintegration process was verified using oily Jianghuang Qingzhi Tablets (JQT) as research object. The water absorption and disintegrating process of different drugs, JQT with different materials, and modified dispersible tablet were determined. Results: The water absorption of JQT was lower than that of lactose tablets, and the disintegrating process was slower. The water absorption of different materials prescription of JQT was: CMS-Na-PVPP (1∶1) > PVPP > CMS-Na, and disintegrating process is the same as the former order. The water absorption of JQT after modification enhanced, and disintegration time was significantly shortened. It indicated that the water absorption of raw materials and excipients was stronger, the disintegration was faster. Conclusion: The study proves that water absorption is a key role in the disintegration of CMM dispersible tablets. And co-grinding of silica powder and raw materials is important technology to solve the problem of slow disintegration of CMM dispersible tablets.
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OBJECTIVE:To establish mathematical model of liquid volume added of TCM medicinal broth decoction machine to accurately calculate liquid volume added in the process of medicinal herb decocting,so as to guarantee the quality of medicinal herb decocting. METHODS:The water absorption rate of representative TCM decoction piece with high use frequency were deter-mined,and cluster analysis of water absorption rate of TCM decoction piece was conducted according to closely related index as density,size,shape,moisture. TCM decoction piece with similar water absorption rate were bracketed together,so that of single ingredient TCM decoction piece can be estimated by water absorption of representative TCM decoction piece;the quantity of water evaporation and liquid extrusion were determined among different types of decoction machine (powered by electric and gas);ac-cording to the above parameters,mathematical model of liquid volume of TCM medicinal broth prepared by different types of de-coction machine had been established,and validated with TCM formula. RESULTS:Factors that affected the liquid volume added included the water absorption of each ingredient,the quantity of water evaporation and extrusion function. The mathematical model was liquid volume added=water absorption of each ingredient × quality of decoction piece+the quantity of water evaporation+re-quired amount of liquid-parameters of extrusion function×total weight of decoction piece;in validation test,the percentage of the practical amount of liquid to required amount was within ±5%. CONCLUSIONS:Established model can promote the accuracy li-quid volume added and guarantee the quality of TCM decoction when using TCM decoction machine.
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Clinical swab heads are often coated with biopolymers to improve the recovery and survival of organisms. To assess the effect of swab head material coating, water absorption capacity and capture and release characteristics of four pathogenic bacteria from protein coated and uncoated flocked swabs were determined. Demonstration of no uniformly higher recovery of all test bacteria from coated swabs over their corresponding uncoated swabs suggest importance of physicochemical properties of swab tip material compared with biopolymer coating, for swab selection for clinical applications.
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The objective of this work was to investigate the relationship between poultry PSE meat and water loss of frozen chicken carcass in two experiments. The first experiment was carried out in commercial abattoir. Poultry carcass were classified as PSE meat (n=59) (pH <5.8) and control samples (n=55) (pH >5.8). Water absorption and drip test were performed according to the Brazilian legislation methodologies. The second experiment was carried out with commercial whole five brands frozen carcasses purchased from the local supermarkets (n=30) and analyzed for pH, water holding capacity (WHC) and drip test. PSE poultry meats absorbed 3.59% of water during the processing similar to the control samples; however, released 0.38% more water during thawing of the carcasses. From these five brands evaluated, three presented drip values above 6.0%. The highest drip value was showed by the brand sample that had pH and WHC values characteristics of PSE meat. It could be postulated that PSE meat phenomenon promoted more water release during thawing leading to a misinterpretation in relation to the Brazilian legislation for water carcass liberation during thawing.
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Una alternativa para resolver el problema del déficit global de proteínas ha sido la utilización de tortas desgrasadas generadas por la extracción de aceite de fuentes vegetales tales como raps, soya, lupino, etc, proceso que al mismo tiempo incrementa el contenido proteico, siendo factible que sea usada para enriquecer algunos tipos de alimentos. Tal es el caso de la avellana chilena (Gevuina avellana, Mol), especie monotípica caracterizada por su elevado porcentaje de aceite (50%) y cuya torta desgrasada podría utilizarse para obtener un aislado proteico. Con este fin se optimizaron las condiciones de extracción de proteína utilizando para ello la metodología superficie de respuesta (MSR) seleccionando el diseño central compuesto, tres variables independientes: tiempo de contacto de la torta con el solvente, relación muestra/solvente y pH, con 5 niveles de trabajo cada uno y tres replicaciones en el punto central. Los datos fueron sometidos a un análisis de regresión y después de ANOVA. El primero para determinar la ecuación polinómica y el segundo para seleccionar los factores de control con efecto significativo sobre el rendimiento de la proteína. La mejor combinación de los factores resultó ser tiempo entre 30 y 40 minutos, pH entre 9 y 9,5 y la relación muestra/ solvente entre 1/15 a 1/16, con un rendimiento final de 76%. En cuanto a las características físicas esta fueron: densidad aparente 0,504 g/cm3, compactación 43,34% y color amarillo claro. El análisis proximal mostró una concentración de proteínas de 76%, hidratos de carbono 13%, fibra cruda 0,68% y aceite 1,29%. En cuanto a las propiedades funcionales destacó absorción de agua (320 g/100 g), absorción de aceite (410 g/100g) y capacidad espumante (221, 05 %).
Establishment of optimun conditions in order to obtain a protein isolate from Chilean Hazelnut. An alternative to solve the problem of the overall deficit of proteins has been the use of defatted cakes generated by the extraction of oil from vegetable sources such as rapeseed, soybean, lupin, etc. This process at the same time increases the protein content, making this feasible to be used to enrich some types of food. This is the case of the chilean hazelnut (Gevuina avellana, Mol), monotypic species characterized by their high percentage of oil (50%) and whose defatted cake isolated protein could be used to obtain an isolated protein. For this purpose optimized conditions of extraction of protein were carried out using the surface response methodology (SRM) and a central composite design with three independent variables: time of contact of the cake with the solvent, sample /solvent ratio and pH was used. All variables were controlled at five different levels. The data were subjected to an analysis of regression and ANOVA, the first to determine the polynomial equation and the second to select the control factors with significant effect on the extraction of the protein. The best combination of factors turned out to be: time between 30 and 40 minutes, pH between 9 and 9.5 and a relationship sample / solvent between 1/15 to 1/16 with a final yield of 76%. The physical characteristics were: density 0,504 g/cm3, compaction 43, 34 % apparent and pale yellow. Proximal analysis showed a concentration of protein of 76%, 13%, raw fiber carbohydrate 0.68% and oil 1.29%. With regard to the functional properties emphasized water absorption (320 g / 100 g), absorption of oil (410 g / 100 g) and foaming capacity (221 %).
Subject(s)
Corylus/chemistry , Food Handling/methods , Plant Proteins/isolation & purification , Chile , Nutritive Value , Plant Proteins/chemistryABSTRACT
The different denture base materials and their processing techniques are developing in the field of removable and fixed prosthodontics. The polymers, especially acrylic resins are entered in this field more than 70 years ago and it is most widely used and material of choice around 80% world wide. Initially acrylic resins were polymerized by heat, later they developed using chemical accelerators for polymerization and termed as selfcure resins. The use of microwave energy to polymerize acrylic denture base in a 400 watt microwave oven for 2.5 minutes was reported in 1968 and properties ware discussed. The present study is designed to compare the residual monomer content in 24,48,72,96 and 120 hours periods of time and water absorption after 10 days in acrylic resin samples processed with conventional heat cure polymerization method and microwave polymerization method.
ABSTRACT
O feijão (Phaseolus vulgaris L.) apresenta alto valor nutricional, entretanto, quando armazenado em condições não apropriadas torna-se endurecido e resistente ao cozimento. O objetivo deste trabalho foi avaliar a qualidade para o cozimento e a qualidade nutricional de grãos de genótipos de feijão dos grupos preto (Macanudo, Guapo Brilhante e BRS Campeiro) e de cor (Carioca, Pérola e LH 5) armazenados sob refrigeração. Os seis genótipos de feijão foram avaliados imediatamente após a colheita e os grãos que foram avaliados após seis meses de armazenamento passaram por prévia secagem em estufa (65 a 70°C), até umidade média de 13 por cento, foram acondicionados em sacos de polietilieno e armazenados em câmara fria a 0°C e a 50 por cento de umidade relativa. Avaliou-se a qualidade para o cozimento (absorção de água, grãos normais, grãos hardshell e tempo de cozimento), a coloração do tegumento dos grãos e a qualidade nutricional (proteína, potássio, ferro e zinco). Os genótipos do grupo preto (Macanudo e BRS Campeiro) mantêm a qualidade para o cozimento, a claridade do tegumento dos grãos e a qualidade nutricional por seis meses de armazenamento refrigerado. Os genótipos do grupo de cor (Carioca, Pérola e LH 5) apresentam escurecimento do tegumento dos grãos, mas a qualidade nutricional não é alterada no armazenamento refrigerado por seis meses.
The common bean (Phaseolus vulgaris L.) presents higher nutritional quality, however when stored in undesirable conditions, become hardened and resistant to cooking. The aim of this research was to evaluate the effect of refrigeration storage on the cooking and nutritional quality of common bean genotypes of the black (Macanudo, Guapo Brilhante and BRS Campeiro) and color (Carioca, Pérola and LH 5) group. The six genotypes were evaluated immediately after harvest time and the grains that were evaluated after six months of storage, were dried in hot-house until 13 percent moisture content. The grains were reserved in plastic bag and storaged in refrigeration under 0°C and at 50 percent of relative humidity. It was evaluated cooking quality (water absorption, normal grains, hardshell grains and cooking time), the color of grains tegument and the nutritional quality (protein, potassium, iron and zinc) were evaluated as well. The genotypes of black group (Macanudo and BRS Campeiro) keep the quality for cooking, the clarity of grains tegument and nutritional quality after six months of storage. The genotypes of the color group (Carioca, Pérola and LH 5) present darkening on the grains tegument, but the nutritional quality is not modified after six months of storage.
ABSTRACT
Conduziu-se este trabalho,com o objetivo de estudar as propriedades funcionais tecnológicas de extrusados de terceira geração obtidos de misturas de farinhas de pupunha (Bactris gasipaes Kunth.) e mandioca (Manihot esculenta Crantz), por meio das análises de densidade aparente, índice de absorção de água, índice de solubilidade em água e viscosidade de pasta (RVA). Os extrusados foram formulados, adicionando-se 15, 20 e 25 por cento de farinha de pupunha à farinha de mandioca, sendo processados em extrusora monorosca, escala piloto. Os parâmetros de extrusão foram fixos, utilizando-se cinco zonas de extrusão com temperaturas de 30ºC, 40ºC, 60ºC, 65ºC e 70ºC; velocidade do parafuso 177rpm; taxa de alimentação 292g/min e matriz laminar de 1mm. Os extrusados de terceira geração obtidos apresentaram valores relativamente baixos ou intermediários de IAA e ISA, variando de 5,01 a 6,48g/g e 5,37 a 7,34 por cento para IAA e ISA, respectivamente. Após o processo de fritura dos extrusados, observou-se expansão e, consequentemente, redução na densidade aparente dos mesmos. O desenvolvimento ou aplicação de tecnologias como a extrusão, que permitam o aproveitamento de matérias-primas regionais, entre elas a mandioca e a pupunha, é uma forma de agregação de valor às riquezas existentes e, ao mesmo tempo, possibilita a diversificação de novos produtos alimentícios prontos para o consumo.
The objective of this work was to study the technological functional properties of third generation extruded products obtained from cassava (Manihot esculenta Crantz) and pupunha (Bactris gasipaes Kunth.) flour mixtures, in terms of apparent density, water absorption index (WAI), water solubility index (WSI) and paste viscosity. The extruded products were formulated by adding 15 percent, 20 percent or 25 percent pupunha flour to cassava flour, and processing the mixtures in a pilot scale single screw extruder. The extrusion parameters were fixed by using five extrusion zones (at 30ºC, 40ºC, 60ºC, 65ºC, and 70ºC); screw speed, 177 rpm; feed rate, 292g/min; laminar matrix with 1 mm. The formed third generation extruded presented relatively low or intermediate values of WAI and WSI. After being fried, the extruded elements were expanded and thus their apparent density were reduced. Development or application of technologies such as extrusion, which allow utilization of regional raw food materials such as cassava and pupunha, is a way of aggregating value to the natural resources, at the same time allowing development of new food products ready for consumption.
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STATEMENT OF PROBLEM: The increasing demand for esthetic restorations has been required developing new materials for tooth colored restoration. Ceromer (Ceramic Optimized Polymer) has some advantages over porcelain, and has gained increasing popularity in restorative dentistry. However, there is little information on the dimensional changes in a clinical restoration in moist conditions. PURPOSE: This study examined the dimensional changes in Ceromer restorations with a clinical crown shape that were fabricated in a clinical manner. MATERIAL AND METHODS: The crowns for the maxillary central incisor were fabricated with two Ceromers (BelleGlass(R) and Targis(R)) using a similar clinical restoration manufacturing technique. A total of twenty specimens were prepared and immersed in distilled water at room temperature to allow for water absorption. The weight, height and width were measured at 24, 72 and 168 hours. The accumulated ratios of the changes were calculated and evaluated using a paired t-test and an independent independent t-test. RESULTS: The dimensions and weight increased with increasing soaking time. Targis(R) showed significant differences in height and weight between 24 hours and the other times (P < .05). BelleGlass(R) showed significant differences in width and weight between 24 hours and the other times. The two materials showed different changing patterns of the dimensions but there were no statistically significant differences between them. CONCLUSION: The dimensions and weight of the Ceromer restorations were changed by water absorption. The clinical crown shaped specimen showed more complicated dimensional changes than the simplified specimens.
Subject(s)
Absorption , Ceramics , Composite Resins , Crowns , Dental Porcelain , Dentistry , Incisor , Tooth , WaterABSTRACT
Fiber reinforced composite (FRC) has been widely used in operative and prosthetic fields of dentistry and its use is expanding into the orthodontic field. The purpose of this study was to examine the changes of flexural properties of FRC reinforced with silica glass fiber (FibreKor(R), Jeneric/Pentron Inc., Wallingford, U.S.A.) according to the duration of water absorption. Specimens were grouped according to their shape as round and rectangular cross sections, and were immersed in distilled water at room temperature (23 degrees C) for 0 hour, 1 hour, 1 week, 15 days, 1 month and 3 months. The number of specimens was 5 for each duration and bending test was done using a torque tester. The flexural stiffness after 24 hour water immersion was reduced to 59% for round specimens and 25% for rectangular specimens and after 3 months of water immersion it was reduced to 29% and 19% stiffness of the 0 hour-specimen respectively. Yield flexural moment after 24 hour water immersion was reduced to 45% for round specimens and 76% for rectangular specimens and after 3 months of water immersion it was reduced to 29% and 60% stiffness of the 0 hour-specimen respectively. Ultimate flexural moment after 24 hour water immersion was reduced to 36% for round specimens and 76% for rectangular specimens and after 3 months of water immersion it was reduced to 25% and 37% stiffness of 0 hour-specimen respectively. Those results suggested that the flexural stiffness of FibreKor(R) decreased greatly after initial water immersion. Consequently, further research for the maintenance of strength against water will be necessary.
Subject(s)
Absorption , Dentistry , Glass , Immersion , Silicon Dioxide , Torque , WaterABSTRACT
@#A new kind of medical sponges,ionic polyvinyl alcohol sponges(i-PVA sponges)were prepared by surface-grafting of acrylic acid onto acetal-PVA sponges.i-PVA sponges obtained show excellent hydrophilicity and water-absorption.The i-PVA sponges are three dimentional porous network.Because there are great amount of carboxyl and sodium carboxylate groups on PVA molecule chains,the speed of water absorption and water-absorptivity is >2.9mm/s and >15 times respectively.That is,in the case of the cataract-extraction,the polyion-modified sponges much more advantageous than any traditional nonionic polymer sponges.