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1.
Arq. bras. med. vet. zootec. (Online) ; 72(3): 827-835, May-June, 2020. ilus, tab
Article in Portuguese | ID: biblio-1129486

ABSTRACT

O colágeno é sintetizado e segregado no espaço extracelular e organizados em fibrilas estriadas de acordo com o tipo de tecido. Utilizaram-se 24 coelhos brancos da raça Nova Zelândia, com idade de 12 meses e com 3,0kg de peso corporal, para avaliar a porcentagem de colágeno das feridas cutâneas tratadas com plasma rico em plaquetas de equino e pomada contendo gentamicina, sulfanilamida, sulfadiazina, ureia e vitamina A. Os animais foram separados em quatro grupos de igual número e submetidos à remoção de pele na região das linhas médias dorsal torácica (feridas tratadas) e lombar (feridas controle). As feridas torácicas foram tratadas com plasma rico em plaqueta de equino e pomada contendo gentamicina, sulfanilamida, sulfadiazina, ureia e vitamina A, e as do grupo controle somente com a pomada. Dos animais do grupo I, foi coletado tecido cutâneo, para a avaliação histológica e a ultraestrutural, com três dias de pós-operatório; dos animais do grupo II, com sete dias; do grupo III, com 14 dias; e do grupo IV, com 21 dias. Decorrido o período de avaliação de cada grupo, foi coletado fragmento de pele para avaliação da porcentagem de colágeno, bem como do diâmetro e da densidade da fibrila de colágeno por microscopia eletrônica de transmissão. O tratamento com PRP de equino associado à aplicação tópica da pomada mostrou-se eficaz na maturação das fibrilas colágenas e na antecipação do processo cicatricial.(AU)


Collagen is synthesized and secreted into the extracellular space and organized into striated fibrils according to the tissue type. This study evaluated the concentration of collagen in rabbit skin wounds treated with equine platelet-rich plasma (PRP) and ointment containing gentamicin, sulfanilamide, sulfadiazine, urea, and vitamin A. Twenty-four New Zealand white rabbits aged 2 to 12 months and weighing 3.0kg were included. The animals were allocated equally into four groups and the skin was removed from the thoracic dorsal midline (treated wound) and lumbar (control wound) regions. The thoracic wounds were treated with equine PRP and ointment containing gentamicin, sulfanilamide, sulfadiazine, urea, and vitamin A, and the control group was treated with the ointment alone. For histological and ultrastructural assessment, cutaneous tissue was collected on postoperative days 3 (group I), 7 (group II), 14 (group III), and 21 (group IV). After the evaluation period, in each group, a skin fragment was collected for analysis of the collagen concentration, as well as the collagen fibril diameter and density by transmission electron microscopy. The results indicated that treatment with equine PRP combined with topical application of the ointment was effective in facilitating the maturation of collagen fibrils and the wound healing process.(AU)


Subject(s)
Animals , Rabbits , Wound Healing/physiology , Wounds and Injuries/rehabilitation , Wounds and Injuries/veterinary , Collagen/ultrastructure , Platelet-Rich Plasma , Sulfadiazine/administration & dosage , Sulfanilamides/administration & dosage , Urea/administration & dosage , Vitamin A/administration & dosage , Gentamicins/administration & dosage , Horses
2.
J. appl. oral sci ; 26: e20170573, 2018. tab, graf
Article in English | LILACS | ID: biblio-954500

ABSTRACT

Abstract Objectives A single-blinded, randomized, parallel clinical trial evaluated the use of 37% carbamide peroxide (CP) on bleaching effectiveness and tooth sensitivity reported by patients undergoing in-office tooth bleaching, in comparison with the results of using 35% hydrogen peroxide. Material and Methods Forty patients were allocated to receive two sessions of in-office tooth bleaching using either 35% hydrogen peroxide (HP) or 37% CP. Each patient's sensitivity level was evaluated during and up to 24 h after bleaching. The effectiveness of the bleaching procedures was evaluated with a spectrophotometer one week after each session and 30 days after the last session. The impact of tooth bleaching on the patients' perceptions regarding smile changes, in addition to the bleaching procedures and their results, were also recorded. Absolute and relative sensitivity risks were calculated. Data on sensitivity level were analyzed using the Mann-Whitney or T-test, and data from the color evaluation were subjected to 2-way repeated measures ANOVA. Results The use of CP reduced the risk and level of tooth sensitivity to values close to zero, whereas the difference between the bleaching agents disappeared after 24 h. An increased bleaching effect was observed for HP, mainly due to an improved reduction of redness and yellowness. Participants perceived improved tooth bleaching for HP and reduced sensitivity for CP, but no differences regarding the comfort of the techniques were noted. Conclusions In our study, 37% CP resulted in reduced tooth sensitivity but decreased the tooth bleaching effectiveness. However, both bleaching agents resulted in high levels of patient satisfaction.


Subject(s)
Humans , Male , Female , Adult , Young Adult , Peroxides/administration & dosage , Tooth Bleaching/methods , Urea/analogs & derivatives , Dentin/drug effects , Dentin Sensitivity/prevention & control , Tooth Bleaching Agents/administration & dosage , Hydrogen Peroxide/administration & dosage , Peroxides/adverse effects , Time Factors , Tooth Bleaching/adverse effects , Urea/administration & dosage , Urea/adverse effects , Single-Blind Method , Reproducibility of Results , Risk Factors , Analysis of Variance , Treatment Outcome , Statistics, Nonparametric , Risk Assessment , Dentin Sensitivity/chemically induced , Tooth Bleaching Agents/adverse effects , Visual Analog Scale , Carbamide Peroxide , Hydrogen Peroxide/adverse effects
3.
Arq. bras. med. vet. zootec ; 67(2): 564-572, Mar-Apr/2015. tab
Article in Portuguese | ID: lil-747039

ABSTRACT

Avaliou-se o efeito da adição de teores crescentes de ureia (0,0; 0,5 e 1,0%) na matéria natural da cana-de-açúcar sobre a produção e composição do leite, eficiência alimentar e viabilidade econômica. Foram utilizadas 18 vacas em lactação, com produção média inicial de 21,3±0,8kg/dia de leite e com 83±7 dias em lactação, distribuídas em delineamento ensaio de reversão do tipo switch-back, 3x3. As dietas experimentais foram constituídas de cana-de-açúcar como volumoso único e concentrado, na relação de 50:50 (base MS). Não houve efeito da suplementação dos diferentes teores de ureia sobre a produção e composição do leite. Contudo, a eficiência alimentar (produção de leite/consumo de matéria seca) foi melhor nas dietas em que se utilizou ureia, sendo 1,14; 1,17 e 1,17, respectivamente, para as dietas com 0,0; 0,5 e 1,0% de ureia (P<0,05). Considerando-se apenas o custo alimentar, todas as dietas apresentaram saldo positivo, sendo que a dieta com 1,0% de ureia apresentou o melhor saldo.(AU)


We studied the effect of increasing 0.0, 0.5 and 1.0% urea in natural sugar cane on cow milk production and composition, food productivity and economic viability. Eighteen lactating cows were studied, they had avarage milk production of 21.3±0.8kg/day and were 83±7 days in lactation in a switch-back, 3 x 3 design. The experimental diets consisted of a unique concentrated sugar cane portion with the 50:50 relation (MS base). The results showed no effect of different urea concentrations on the milk production or composition. However, food productivity (milk production/dry matter consumption) was 1.14; 1.17, and 1.17 respectively on urea diets of 0.0; 0.5 and 1.0% (P<0.05). Considering only the alimentary cost, all diets had a positive balance, and the 1.0% urea concentration was the best.(AU)


Subject(s)
Animals , Female , Cattle , Lactation , Milk/chemistry , Food Additives , Urea/administration & dosage , Costs and Cost Analysis
4.
Braz. oral res. (Online) ; 29(1): 1-7, 2015. tab, ilus
Article in English | LILACS | ID: lil-777227

ABSTRACT

Dental bleaching has become one of the most frequently requested esthetic treatments in dental offices. Despite the high clinical success observed with this procedure, some adverse effects have been reported, including a potential for developing premalignant lesions, root resorption and tooth sensitivity, especially when misused. The aim of this study was to evaluate the genotoxic response using a micronucleus (MN) assay, after the application of two concentrations of carbamide peroxide. Thirty-seven patients were divided into two groups and randomly received either a 10% carbamide peroxide (CP) (19) or a 16% carbamide peroxide (18) concentration for 21 days in individual dental trays. Gingival margin cells were collected immediately before the first use (baseline), and then 15 and 45 days after baseline. The cells were placed on a histological slide, stained by the Feulgen technique, and evaluated by an experienced blinded examiner. One thousand cells per slide were counted, and the MN rate was determined. The two groups were analyzed by the Wilcoxon rank-sum test and the Kruskal-Wallis equality-of-populations rank test. A slight increase in MN was observed for both groups, in comparison with the baseline, at 15 days. However, no difference was observed between the two groups (10% and 16%), at either 15 or 45 days (p = 0.90). When bleaching is not prolonged or not performed very frequently, bleaching agents containing carbamide peroxide alone will not cause mutagenic stress on gingival epithelial cells.


Subject(s)
Adult , Female , Humans , Male , Young Adult , Gingiva/drug effects , Peroxides/adverse effects , Tooth Bleaching/adverse effects , Urea/analogs & derivatives , Epithelial Cells/drug effects , Micronucleus Tests , Mouth Mucosa/drug effects , Peroxides/administration & dosage , Random Allocation , Statistics, Nonparametric , Time Factors , Treatment Outcome , Tooth Bleaching/methods , Urea/administration & dosage , Urea/adverse effects
5.
Arq. neuropsiquiatr ; 72(2): 91-98, 02/2014. tab, graf
Article in English | LILACS | ID: lil-702554

ABSTRACT

Objective : To assess the efficacy of anti-xerostomic topical medication (urea 10%) in patients with burning mouth syndrome (BMS). Method : Thirty-eight subjects diagnosed with BMS according to the International Association for the Study of Pain guidelines were randomized to either placebo (5% sodium carboxymethylcellulose, 0.15% methyl paraben, and 10% glycerol in distilled water qsp 100 g) or treatment (urea 10%) to be applied to the oral cavity 3-4 times per day for 3 months. The patients were evaluated before and after treatment with the following instruments: the EDOF-HC protocol (Orofacial Pain Clinic – Hospital das Clínicas), a xerostomia questionnaire, and quantitative sensory testing. Results : There were no differences in salivary flow or gustative, olfactory, or sensory thresholds (P>0.05). Fifteen (60%) patients reported improvement with the treatments (P=0.336). Conclusion : In conclusion, there were no differences between groups, and both exhibited an association between reported improvement and salivation. .


Objetivo : Avaliar a eficácia do uso de medicação tópica anti xerostomica (ureia 10%) em pacientes com síndrome de ardência bucal. Método : Trinta e oito sujeitos diagnosticados com síndrome de ardência bucal de acordo com os critérios da Associação Internacional para Estudo da Dor foram randomizados para grupo placebo (5% de carboximetilcelulose de sódio, 0,15% de metilparabeno e 10% de glicerol em água destilada qsp 100g) ou grupo tratamento (ureia 10%) para ser aplicada na cavidade oral 3-4 vezes ao dia, durante três meses. Os pacientes foram avaliados antes e depois do tratamento: protocolo EDOF-HC, questionário de xerostomia, testes sensitivos quantitativos. Resultados : Não houve diferenças no fluxo salivar, limiares gustativos, olfativos e somestésicos (Mann-Whitney P>0,05). Quinze (60%) dos pacientes tiveram melhora com o tratamento (P=0,336, oneway ANOVA ). Conclusão : Em conclusão não houve diferenças entre os grupos, ambos apresentaram uma associação entre melhora e salivação. .


Subject(s)
Adult , Aged , Aged, 80 and over , Female , Humans , Male , Middle Aged , Amitriptyline/therapeutic use , Analgesics, Non-Narcotic/therapeutic use , Burning Mouth Syndrome/drug therapy , Urea/administration & dosage , Xerostomia/complications , Xerostomia/drug therapy , Burning Mouth Syndrome/complications , Burning Mouth Syndrome/physiopathology , Case-Control Studies , Double-Blind Method , Salivation , Sensory Thresholds , Socioeconomic Factors , Xerostomia/physiopathology
6.
Rev. colomb. biotecnol ; 15(2): 38-46, jul.-dic. 2013. graf
Article in Spanish | LILACS | ID: lil-703335

ABSTRACT

Se comparó la eficiencia de sistemas de cultivos discontinuos alimentados versus cultivos discontinuos convencionales, en cuanto a concentración de nitrógeno, adicionando 0,2 mM de urea cada tres días al final de la fase exponencial, durante 21 días. Se realizaron cultivos con un volumen de 1500 mL a 15 y 35 UPS de salinidad, enriquecidos con medio ALGAL 8mM NaNO3, a 238 µmol q m-2 s-1, aireación constante, fotoperiodo 12:12 horas y temperatura de 29 ±3°C. Phormidium sp. posee la capacidad de hidrolizar la urea; mostrando una asimilación de 65±7,07% de la misma, con la mayor producción (p<0,05) de clorofila a, ficocianina y proteínas de 20,26±1,24; 203,47±12,83 y 707,87±28,47 µg mL-1en los cultivos alimentados. La producción de pigmentos vario en el tiempo, independientemente a la salinidad y sistema de cultivo, mientras que la producción de proteínas y carbohidratos totales fue directamente proporcional a la edad del cultivo, con valores máximos de 612,74 ± 5,41 µg mL-1 y 8,96±0,08 mg mL-1 respectivamente a los 31 días. La síntesis de lípidos y EPS fueron influenciadas (p<0,05) por la salinidad, presentando los máximos de lípidos a 15 UPS con 12,22±2,91µg mL-1, y los EPS se incrementaron a 35 UPS con 2,00 ± 0,26 y 2,03 ± 0,15 mg mL-1. Estos resultados determinan que los cultivos de Phormidium sp. alimentados con urea y a salinidades de 15 y 35 UPS, representan una alternativa económica para la producción de clorofila a, ficocianina y proteínas, incrementándose un 31,04; 40,72 y 31,94 % respectivamente en comparación con cultivos no alimentados.


Fed-batch system efficiency versus batch cultures was compared in relation to nitrogen concentration, adding 0,2mM urea at the end of the exponential phase, during 21 days. Cultures were carried out in 1500 mL to 1.5 and 3.5 UPS of salinity, enriched with Algal medium 8mM NaNO3, 238 mol q m-2 s-1, constant aeration, photoperiod 12:12 h. and 29 ±3°C. Phormidium sp. is able to hydrolyze urea; showing a total assimilation of 65±7.07%, with the highest (p< 0.05) chlorophyll a, phycocyanin and protein production of 20.26 ± 1.24, 203.47 ± 12.83 and 707.87 ± 28.47 µg mL-1 in the fed-batch cultures. On the other hand, pigment production varies in time, regardless salinity and culture system. Proteins and total carbohydrate production were directly proportional to the age of cultures, with maximum values of 612.74 ± 5.41 µg mL-1 and 8.96 ± 0.08 mg mL-1, respectively. Lipid and EPS were influenced (p< 0.05) by salinity, showing maximum of lipids at 15 UPS with 12.22±2.91 µg mL-1, and EPS at 15 and 35 UPS with 2.00 ± 0.26 and 2.03 ± 0.15 mg mL-1. These results determine that Phormidium sp. cultures fed with urea, to salinities of 15-35 UPS, represent an economic alternative for chlorophyll a, phycocyanin and protein production, with an increase of 31.04, 40.72 and 31.94% respectively in comparison with non-fed cultures.


Subject(s)
Cyanobacteria/classification , Cyanobacteria/growth & development , Cyanobacteria/chemistry , Salinity , Urea/administration & dosage , Urea/isolation & purification , Urea/analogs & derivatives , Urea/immunology , Urea/chemical synthesis , Urea , Chlorophyll , Phycocyanin , Proteins
7.
Braz. dent. j ; 24(5): 517-521, Sep-Oct/2013. tab, graf
Article in English | LILACS | ID: lil-697629

ABSTRACT

The aim of this study was to compare the effect of a 16% carbamide peroxide (CP) gel and a 10% CP gel on mineralized enamel content and morphology. Enamel blocks from bovine incisors were subjected to a 14-day treatment (8 h/day) with 10% or 16% CP gels. Knoop microhardness was evaluated before bleaching and at 1, 7 or 14 days after this treatment (50 g/15 s). Mineral content (energy-dispersive x-ray spectroscopy), surface roughness and topography (atomic force microscopy) were evaluated at the 14-day period. Data were analyzed statistically by two-way ANOVA and Tukey's test (α=0.05). Significant microhardness reduction was observed at the 7 th and 14 th days for 10% CP gel, and for all bleaching times for 16% CP gel (p<0.05). At the 14-day period, a significant decrease in Ca and P content, increase on surface roughness (p<0.05) as well as on picks and valleys distance were observed when both bleaching gels were used. These enamel alterations were more intense for 16% CP gel. It was concluded that both CP-based gels promoted loss of mineral structure from enamel, resulting in a rough and porous surface. However, 16% CP gel caused the most intense adverse effects on enamel.


O objetivo do presente estudo foi comparar o efeito de um gel com 16% de peróxido de carbamida (PC) sobre a estrutura mineral e morfologia do esmalte dental com os efeitos de um gel com 10% de PC. Blocos de esmalte provenientes de incisivos bovinos foram submetidos a 14 dias de tratamento (8 h/dia) com géis com 10 ou 16% de PC. A microdureza Knoop foi avaliada antes do clareamento e 1, 7 e 14 dias pós-tratamento (50 g/15 s). O conteúdo mineral (EDX), rugosidade de superfície e topografia (MFA) foram avaliados no período de 14 dias (ANOVA a dois critérios e teste de Tukey; α=0,05). Redução significante na microdureza foi observada nos períodos de 7 e 14 dias para o gel com 10% de PC, e em todos os períodos para o gel com 16% de PC (p<0,05). No período de 14 dias, uma diminuição significante no conteúdo de Ca e P, aumento na rugosidade de superfície (p<0,05), bem como na distância entre picos e vales foram observados para ambos os agentes clareadores usados. Estas alterações foram mais intensas para o gel com 16% de PC. Pôde-se concluir que ambos os géis à base de PC promoveram perda de estrutura mineral do esmalte, resultando em superfície mais rugosa e porosa. Porém, o gel com 16% de PC causou efeitos adversos mais intensos no esmalte dental.


Subject(s)
Humans , Dental Enamel/drug effects , Peroxides/adverse effects , Tooth Bleaching/methods , Tooth Demineralization/chemically induced , Urea/analogs & derivatives , Gels , Hardness Tests , Microscopy, Atomic Force , Peroxides/administration & dosage , Spectrometry, X-Ray Emission , Urea/administration & dosage , Urea/adverse effects
8.
Article in English | IMSEAR | ID: sea-140185

ABSTRACT

Objective: Intraoral corrosion of dental alloys has biological, functional, and esthetic consequences. Since it is well known that the salivary urea concentrations undergo changes with various diseases, the present study was undertaken to determine the effect of salivary urea concentrations on the corrosion behavior of commonly used dental casting alloys. Materials and Methods: Three casting alloys were subjected to polarization scans in synthetic saliva with three different urea concentrations. Results: Cyclic polarization clearly showed that urea levels above 20 mg/100 ml decreased corrosion current densities, increased the corrosion potentials and, at much higher urea levels, the breakdown potentials. Conclusion: The data indicate that elevated urea levels reduced the corrosion susceptibility of all alloys, possibly through adsorption of organics onto the metal surface. This study indicates that corrosion testing performed in sterile saline or synthetic saliva without organic components could be misleading.


Subject(s)
Adsorption , Carbon Compounds, Inorganic/chemistry , Chromium Alloys/chemistry , Corrosion , Dental Alloys/chemistry , Dental Polishing/methods , Gold Alloys/chemistry , Humans , Materials Testing , Platinum/chemistry , Polarography , Saliva, Artificial/chemistry , Silicon Compounds/chemistry , Surface Properties , Urea/administration & dosage , Urea/chemistry
9.
Arq. bras. med. vet. zootec ; 63(4): 895-904, ago. 2011. tab
Article in Portuguese | LILACS | ID: lil-599609

ABSTRACT

Avaliaram-se fontes proteicas em suplementos para novilhos em pastagens de Brachiaria decumbens Stapf., durante a transição seca-águas, sobre as características nutricionais. Utilizaram-se quatro animais Holandês x Zebu, não castrados, com média de peso de 300kg, fistulados no esôfago, rúmen e abomaso, distribuídos em delineamento em quadrado latino 4x4. Avaliaram-se suplementos isoproteicos, balanceados para 38 por cento de proteína bruta (PB), sendo um tratamento controle mistura mineral (MM); e três suplementos à base de grãos de milho moído + ureia (MU); grãos de milho moído + farelo de soja (MFS) e farelo de algodão 38 por cento PB (FA), fornecidos na quantidade de 0,17 por cento do peso vivo (PV). O consumo de fibra em detergente neutro pelos animais do tratamento MU, de 12,1g/kg PV, foi maior em 19,9 por cento do que o observado para os dos tratamentos MM e MFS, 10,2g/kg PV, e semelhante ao observado para os do tratamento FA, 11,0g/kg PV. Foram observados valores mais altos de digestibilidade aparente total da matéria seca (MS) para os tratamentos MU e MFS em relação aos demais. Os valores de pH ruminal, produção de nitrogênio microbiano e eficiência de síntese microbiana não foram influenciados pelos tratamentos. A suplementação com MU proporciona maior consumo e digestibilidade aparente total da MS em relação ao tratamento MM.


This study was conducted to evaluate protein sources in supplements for bulls grazing Brachiaria decumbens Stap., in the dry-rainy transition season, regarding nutritional characteristics. Four Holstein x Zebu bulls (300kg of body weight - BW) fitted with esophageal, ruminal, and abomasal cannulas, allotted in a latin square experimental design 4x4. The treatments were protein supplements with 38 percent of crude protein (CP) based on grounded corn grain + urea (GCU); grounded corn grain + soybean meal (GCSB); and cotton seed meal (38 percent CP) (CSM), supplied at a level of 0.17 percent BW, and a mineral mix control treatment (MM). The animals fed diets of GCU treatment showed neutral detergent fiber (NDF) intake of 12.1g/kg of BW, 19.9 percent greater than the observed on animals fed diets of MM and GCSB, 10.2 g/kg of BW, and similar to the NDF intake found for animals fed CSM treatment, 11.0g/kg of BW. The dry matter (DM) total apparent digestibility (TAD) was higher for GCU and GCSB treatments. The ruminal pH, microbial nitrogen production (MNP), and microbial synthesis efficiency (MSE) were not influenced by the treatments. The supplementation with corn and urea provides greater DM intake and digestibility when compared to the mineral mix.


Subject(s)
Animals , Food Additives/administration & dosage , Cattle/growth & development , Brachiaria/growth & development , Droughts , Gossypium , Proteins/administration & dosage , Soybeans , Urea/administration & dosage , Zea mays
10.
Arq. bras. med. vet. zootec ; 63(4): 905-913, ago. 2011. tab
Article in Portuguese | LILACS | ID: lil-599610

ABSTRACT

Foram avaliados os consumos e as digestibilidades aparentes da matéria seca (MS), matéria orgânica, proteína bruta e os consumos da matéria seca digestível e dos nutrientes digestíveis totais (NDT), em 18 novilhas Holandês x Zebu, distribuídas em blocos ao acaso, alimentadas com cana-de-açúcar acrescida ou não a 1 por cento de óxido de cálcio - na matéria natural - após 24 horas de hidrólise, com diferentes tempos de administração da mistura de ureia e sulfato de amônio - zero e 24 horas antes do fornecimento aos animais. As diferenças entre as médias foram avaliadas por contrastes ortogonais, a 1 por cento de significância. Houve efeito negativo (P<0,01) da adição do óxido de cálcio no consumo de NDT, na digestibilidade aparente da matéria orgânica e na eficiência da utilização do nitrogênio. A administração de ureia no momento da hidrólise causou diminuição no consumo e na digestibilidade aparente da PB. Não houve benefício tanto da inclusão de óxido de cálcio quanto da adição de ureia 24 horas antes do fornecimento aos animais.


We evaluated the intake and apparent digestibility of dry matter, organic matter, crude protein, and intakes of digestible dry matter and total digestible nutrients (TDN) in 18 Holstein-Zebu heifers divided into blocks, fed with diets of sugarcane treated or not with 1 percent in the natural matter of calcium oxide (CaO), after 24 hours of hydrolysis, at different times of administration of the mixture of urea and ammonium sulfate (zero and 24 hours). Differences between means were evaluated by orthogonal contrasts at 1 percent significance. There was a negative effect (P<0.01) to the addition of calcium oxide in TDN intake, apparent digestibility of organic matter and the efficiency of nitrogen utilization. The administration of a mixture of urea and ammonium sulfate at the time of hydrolysis caused a decrease in consumption and apparent digestibility of crude protein. There was no benefit in the inclusion of calcium oxide nor the addition of urea 24 hours before the animal feeding.


Subject(s)
Animals , Female , Cattle/growth & development , Calcium Oxide , Digestion , Saccharum , Infant Nutritional Physiological Phenomena , Organic Matter , Ammonium Sulfate/administration & dosage , Urea/administration & dosage
11.
J. Health Sci. Inst ; 29(2): 139-142, apr.-jun. 2011. tab
Article in Portuguese | LILACS | ID: lil-606313

ABSTRACT

Objetivo - Comparar a substituição parcial de farelo de soja por uréia sobre a produtividade e qualidade do leite. Métodos - Foram utilizadas 24 vacas Girolanda em lactação em um experimento com delineamento inteiramente casualizado. Dois concentrados foram utilizados: (C) controle, sendo a principal fonte de proteína o farelo de soja e (U) uréia, neste tratamento 1/3 da proteína total foi substituída por nitrogênio não protéico (NNP) oriundo da uréia. Foram avaliadas a produção, a composição e as características físico-químicas do leite. As dietas foram formuladas seguindo as recomendações do NRC (2001) e a nutrição protéica foi acompanhada pela concentração de uréia plasmática. A contagem de células somáticas foi utilizada com a finalidade de monitorar a sanidade da glândula mamária. Resultados - A produção leiteira foi diferente (P<0,05) entre os tratamentos 9,41 para o grupo Uréia vs. 7,98 kg/vaca/dia para o grupo Controle. A composição e as características físico-químicas foram semelhantes entre os tratamentos (P>0,05). Houve redução de 11,5% no custo do concentrado com inclusão de uréia. Conclusão - A substituição parcial do farelo de soja por uréia em dietas para vacas Girolanda mostrou-se uma alternativa viável para a produção leiteira, pois além de aumentar a produção, reduziu os custos com alimentação, sem alterar o valor nutricional do leite.


Objective - To compare the partially replacement of soybean meal by urea on lactation performance in experiment completely randomized. Methods - Twenty four Girolanda dairy cows were used. Two treatments were used: (C) control, being the main source of protein soybean meal and (U) urea, in this treatment 1/3 of total protein was replaced by non-protein nitrogen (NPN) derived from the urea. Milk production, composition and physico-chemical characteristic were measured. Diets were formulated following the recommendations of NRC (2001) and protein diet was accompanied by the concentration of blood urea nitrogen. Somatic cell count was used to monitor udder health. Results - There were differences (P>0.05) among treatments only for milk production 9.41 for urea treatment vs. 7.98 kg/cow/day for control treatment. Milk composition and physico-quimical characteristics were similar among treatments (P>0.05). There was a decrease of 11,5% in the cost of the concentrate with addition of urea. Conclusion - This study indicated that using urea for lactating Girolanda dairy cows had no detrimental effect on lactation performance or on milk nutritional value.


Subject(s)
Animals , Breast-Milk Substitutes , Nitrogen/administration & dosage , Urea/administration & dosage
12.
Arq. gastroenterol ; 48(2): 104-108, Apr.-June 2011. graf, tab
Article in English | LILACS | ID: lil-591158

ABSTRACT

CONTEXT: The standard doses of 13C-urea in 13C-urea breath test is 75 mg. OBJECTIVE: To assess the diagnostic accuracy of 13C-urea breath test containing 25 mg of 13C-urea comparing with the standard doses of 75 mg in the diagnosis of Helicobacter pylori infection. METHODS: Two hundred seventy adult patients (96 males, 174 females, median age 41 years) performed the standard 13C-urea breath test (75 mg 13C-urea) and repeated the 13C-urea breath test using only 25 mg of 13C-urea within a 2 week interval. The test was performed using an infrared isotope analyzer. Patients were considered positive if delta over baseline was >4.0‰ at the gold standard test. RESULTS: One hundred sixty-one (59.6 percent) patients were H. pylori negative and 109 (40.4 percent) were positive by the gold standard test. Using receiver operating characteristic analysis we established a cut-off value of 3.4 percent as the best value of 25 mg 13C-urea breath test to discriminate positive and negative patients, considering the H. pylori prevalence (95 percent CI: 23.9-37.3) at our setting. Therefore, we obtained to 25 mg 13C-urea breath test a diagnostic accuracy of 92.9 percent (95 percent CI: 88.1-97.9), sensitivity 83.5 percent (95 percent CI: 75.4-89.3), specificity 99.4 percent (95 percent CI: 96.6-99.9), positive predictive value 98.3 percent (95 percent CI: 92.4-99.4), and negative predictive value 93.0 percent (95 percent CI: 88.6-96.1). CONCLUSIONS: Low-dose 13C-urea breath test (25 mg 13C-urea) does not reach accuracy sufficient to be recommended in clinical setting where a 30 percent prevalence of H. pylori infection is observed. Further studies should be done to determine the diagnostic accuracy of low doses of 13C-urea in the urea breath test.


CONTEXTO: A dose convencional de 13C-ureia para a realização do teste respiratório com 13C-ureia é 75 mg. OBJETIVO: Determinar a precisão diagnóstica do teste respiratório contendo 25 mg de 13C-ureia comparada com a dose convencional de 75 mg para o diagnóstico de infecção por H. pylori. MÉTODOS: Duzentos e setenta pacientes adultos (96 homens, 174 mulheres, idade mediana de 41 anos) realizaram o teste respiratório convencional (75 mg 13C-ureia) e repetiram o teste respiratório usando apenas 25 mg de 13C-ureia dentro de 2 semanas de intervalo. O teste respiratório foi realizado empregando-se analisador de isótopos por infravermelho. Os pacientes foram considerados positivos quando apresentavam valor delta acima da linha de base >4.0 no teste respiratório convencional (padrão-ouro). RESULTADOS: Cento e sessenta e um pacientes (59,6 por cento) eram H. pylori negativos e 109 (40,4 por cento) eram positivos aos testes respiratórios convencionais. Para definição do melhor ponto de corte discriminatório entre positivos e negativos pelo teste respiratório com 25 mg, foi utilizado a curva ROC, obtendo-se o valor de 3,4 por cento, considerando-se a prevalência de 30,2 por cento (IC 95 por cento: 23.9-37.3) da infecção por H. pylori no laboratório, onde se realizou este estudo. Desta forma, para o teste respiratório com 25 mg foi obtida uma precisão diagnóstica de 92,9 por cento (IC 95 por cento: 88,1-97,9), sensibilidade de 83,5 por cento (IC 95 por cento: 75,4-89,3) e especificidade de 99,4 por cento (IC 95 por cento: 96,6-99,9). CONCLUSÕES: Teste respiratório com dose baixa (25 mg) de 13C-ureia não proporciona precisão suficiente para ser recomendado em ambientes clínicos, onde a prevalência de H. pylori está situada em torno de 30 por cento.


Subject(s)
Adult , Female , Humans , Male , Middle Aged , Young Adult , Breath Tests/methods , Helicobacter pylori , Helicobacter Infections/diagnosis , Urea , Carbon Isotopes , Reproducibility of Results , ROC Curve , Sensitivity and Specificity , Urea/administration & dosage
13.
Braz. dent. j ; 22(1): 32-36, 2011. tab
Article in English | LILACS | ID: lil-582398

ABSTRACT

This study evaluated the influence of bleaching protocols on intrapulpal temperature and fracture strength of the bleached teeth. Ninety maxillary incisors were assigned to 9 groups (n=10): G1: 35 percent carbamide peroxide (35 percent CP), G2: 38 percent hydrogen peroxide (38 percent HP), G3: halogen light, G4: LED-laser, G5: 35 percent CP + halogen light, G6: 38 percent HP + halogen light, G7: 35 percent CP + LED-laser, G8: 38 percent HP + LED-laser, and G9: no treatment (control). Pulp space was widened, a thermocouple was introduced through the apex up to the pulp chamber and the temperature was recorded (°C). The fracture strength (kN) was determined using an Instron machine. Data were analyzed by ANOVA and Tukey's test (p<0.05). The halogen light alone (1.10 ± 0.24) (G3) and associated with 38 percent HP (1.15 ± 0.30) (G6) produced the highest temperature increase, statistically different (p<0.05) from the other groups. G1 (0.15 ± 0.06) and G6 (0.19 ± 0.07) produced the lowest values, statistically different (p<0.05) from G5 (0.65 ± 0.49). The bleaching protocols increased the temperature, but no increment exceeded the critical value of 5.6°C. Neither 35 percent CP nor 38 percent HP or the light sources alone altered the fracture strength of the teeth.


Este estudo avaliou a influência de protocolos de clareamento na temperatura intrapulpar e resistência à fratura de dentes clareados. Noventa incisivos superiores foram divididos em 9 grupos (n=10): G1: peróxido de carbamida a 35 por cento (PC 35 por cento), G2: peróxido de hidrogênio a 38 por cento (PH 38 por cento), G3: luz halógena, G4: LED-laser, G5: PC 35 por cento + luz halógena, G6: PH 38 por cento + luz halógena, G7: PC 35 por cento + LED-laser, G8: PH 38 por cento + LED-laser e G9: sem tratamento (controle). O canal radicular foi alargado, um termopar foi introduzido no ápice até a câmara pulpar e a temperatura foi calculada (°C). A resistência à fratura (kN) foi determinada em máquina Instron. Os dados foram analisados por análise de variância e teste de Tukey (p>0,05). A luz halógena utilizada isoladamente (1,10 ± 0,24) (G3) e associada ao PH 38 por cento (1,15 ± 0,30) (G6) proporcionaram os maiores valores de temperatura, sendo estatisticamente diferentes dos demais grupos (p<0,05). O G1 (0,15 ± 0,06) e o G6 (0,19 ± 0,07) produziram os menores valores de resistência à fratura, sendo estatisticamente diferentes (p<0,05) do G5 (0,65 ± 0,49). Os protocolos de clareamento aumentaram a temperatura, mas nenhum incremento excedeu o valor crítico de 5,6oC. O PC 35 por cento, PH 38 por cento e as fontes de luz utilizadas isoladamente não alteraram a resistência à fratura dos dentes.


Subject(s)
Humans , Body Temperature/drug effects , Dental Pulp/drug effects , Tooth Bleaching Agents/administration & dosage , Tooth Bleaching/methods , Tooth Fractures/prevention & control , Curing Lights, Dental , Dental Stress Analysis , Dental Pulp/physiology , Hydrogen Peroxide/administration & dosage , Incisor/drug effects , Lasers, Semiconductor , Maxilla , Peroxides/administration & dosage , Tooth Bleaching Agents/adverse effects , Tooth Bleaching/adverse effects , Tooth Fractures/etiology , Urea/administration & dosage , Urea/analogs & derivatives
14.
Arq. bras. med. vet. zootec ; 61(3): 662-667, jun. 2009. tab
Article in Portuguese | LILACS | ID: lil-519460

ABSTRACT

Avaliou-se o efeito da inclusão de níveis crescentes de ureia sobre o consumo e a digestibilidade aparente dos nutrientes de dietas contendo coproduto de vitivinícolas desidratado (CVD) e palma forrageira in natura. Foram utilizados 16 ovinos da raça Santa Inês machos, não castrados, com peso médio de 37kg e média de idade de 11 meses. As dietas continham 60 por cento de CVD e 40 por cento de palma forrageira, e níveis crescentes de ureia, 0, 1, 2 e 3 por cento, na matéria seca (MS). O delineamento experimental foi o inteiramente ao acaso, e o experimento foi desenvolvido em dois períodos, com 15 dias de adaptação e cinco dias de coleta cada. Os consumos da MS, fibra em detergente neutro (FDN), carboidratos não fibrosos (CNF) e nutrientes digestíveis totais (NDT) apresentaram comportamento quadrático com valores máximos de 2,04; 0,66; 0,74; 1,50kg/dia, respectivamente. No consumo de proteína bruta (PB), a cada acréscimo de uma unidade percentual de ureia ocorreu aumento de 20 gramas no consumo de PB. Os coeficientes de digestibilidade da MS, PB, FDN e CNF apresentaram comportamento quadrático com valores máximos de 62,5; 85,0; 81,0; e 97,8 por cento, respectivamente. A inclusão de ureia até 2 por cento nas dietas contendo coproduto de vitivinícolas desidratado e palma forrageira in natura possibilitou incrementos no consumo e no coeficiente de digestibilidade dos nutrientes.


The effect of urea levels on intake and apparent digestibility of nutrients in diets containing dried wine grape byproduct and fresh forage cactus was evaluated. Sixteen male, non-castrated, Santa Inês sheep, averaging 37kg and 11-month-old were used. The diets had 60 percent of dried grape byproduct (DGB) and 40 percent of forage cactus, and increasing levels of urea - 0, 1, 2, and 3 percent in dry matter. Completely randomized designs with two periods with 15 adjust days and five days for samples collection was carried out. Dry matter (DM), neuter detergent fiber (NDF), non-fibrous carbohydrates (NFC), and total digestive nutrients (TDN) intakes presented quadratic behavior with maximum values of 2.04; 0.66; 0.74; and 1.50kg/day, respectively. For each increase of an unit percentage of urea an increase of 20 grams in the CP intake occurred. The digestibility coefficients of DM, CP, NDF, and NFC presented quadratic behavior with maximum values of 62.5, 85.0, 81.0, and 97.8 percent, respectively. The inclusion of urea up to 2 percent in the diets containing dried grape byproduct and fresh forage cactus made possible increases in nutrient intake and coefficient of digestibility of nutrients.


Subject(s)
Animals , Male , Animal Nutritional Physiological Phenomena , Digestive System Physiological Phenomena , Feeding Behavior , Opuntia , Sheep , Urea/administration & dosage , Wine Industry
15.
J. appl. oral sci ; 17(3): 254-261, May-June 2009. ilus, tab
Article in English | LILACS | ID: lil-514044

ABSTRACT

Objective: To evaluate the efficacy of 16% carbamide peroxide gel (CP16%), tetrahydrate sodium perborate (SP) and mixture (CP16% + SP), in walking bleaching of non-vital discolored teeth. Materials and methods: Sixty single-rooted human premolars with intact crowns were used and initial color was assessed using Vita shade guide and standardized photos. The teeth were stained using rabbit fresh blood for 18 days and photos of discolored teeth and color evaluation were performed. The teeth were divided into 4 groups (n= 15), according to bleaching agent used: G1) CP16% gel; G2) CP16% gel + SP; G3) SP + distilled water; G4: control.The bleaching agents were replaced twice at 7-day intervals for 21 days. All teeth were evaluated by two endodontists at days 0, 7, 14 and 21 and the color changes were assessed using Vita shade guide and standardized photos. The results were analyzed byKruskal-Wallis and Dunn’s tests (p=0.05). Results: The experimental groups presented statistically similar bleaching results (p>0.05) at the end of 7, 14 and 21 days. These groups presented significantly higher bleaching efficacy than control group (G4) (p<0.05). The mixture CP16% + SP promoted return of original color in 100% of teeth at the end of 21 days. Conclusion: It was concluded that three bleaching agents were effective in bleaching of stained teeth with blood products, especially at the end of 21 days.


Subject(s)
Animals , Humans , Rabbits , Borates/administration & dosage , Oxidants/administration & dosage , Peroxides/administration & dosage , Tooth, Nonvital , Tooth Bleaching/methods , Tooth Discoloration/therapy , Urea/analogs & derivatives , Bicuspid , Blood Stains , Drug Combinations , Urea/administration & dosage
16.
Braz. j. vet. res. anim. sci ; 46(1): 69-76, 2009. tab
Article in Portuguese | LILACS | ID: lil-536958

ABSTRACT

Doze garrotes Girolando nunca alimentados com uréia foram distribuídos em dois grupos de seis animais cada, e induzidos a desenvolver um quadro de intoxicação por amônia através da administração de uréia extrusada ou granulada em dose única (0,5 g/kg PV). Foram determinados no plasma ou soro os teores de amônia, glicose, L-lactato, uréia e creatinina, além do volume globular em sangue total nos seguintes momentos: antes da administração de uréia, no surgimento dos tremores, após o primeiro episódio convulsivo, e após 240 minutos do início do experimento. A hiperamoniemia ocorreu a partir dos primeiro tremores. Maiores glicemia e lactemia-L foram constatadas no momento do ápice da intoxicação (episódio convulsivo), os quais foram superiores ao tempo basal. A produção endógena de uréia aumentou no decorrer do experimento devido à hiperamoniemia (r = 0,57), atingindo seus valores mais altos ao término do experimento. Quanto maior foi o teor de amônia, maiores foram as concentrações de lactato-L, glicose, uréia, creatinina e volume globular. Estes resultados permitem concluir que o grau de hiperamoniemia aumentou a gliconeogênese, a glicólise anaeróbica, a síntese de uréia endógena e o grau de desidratação. Entre as variáveis estudadas os teores de glicose e de lactato-L foram os melhores indicadores para monitorar alterações bioquímicas na intoxicação pela amônia


Twelve yearling Girolando steers never fed urea before were assigned randomly in two groups of six animals each. In both groups were administered intraruminally a single dose (0.5 g/kg BW) of extruded or prilled urea in order to induce ammonia poisoning. Plasma or serum levels of ammonia, urea, creatinine, glucose, L-lactate were determined. Hematocrit values were also recorded. Blood samples were taken before the administration of urea, at the onset of muscle tremors, at the first convulsive episode, and 240 minutes after the beginning of the urea feeding. Hyperammonemia already occured at the time of the first muscle tremors. Glucose and L-lactate levels were higher at the peak of the intoxication (convulsive episode), which were higher compared to the beginning of the experiment.Endogenous production of urea increased during the experiment due to hyperammonemia (r = 0.57), reaching peak levels at the end of the trials. Higher ammonia values lead to increased concentrations ofL-lactate, glucose, urea, creatinine and hematocrit values. These results showed that high levels of ammonia increased glyconeogenesis, anaerobic glycolysis, the endogenous synthesis of urea and the level of dehydration. L-lactate and glucose were the best variables to monitor biochemical changes in cases of ammonia poisoning


Subject(s)
Animals , Ammonia/toxicity , Cattle , Biomarkers/analysis , Urea/administration & dosage
17.
Braz. oral res ; 23(supl.1): 64-70, 2009.
Article in English | LILACS | ID: lil-528431

ABSTRACT

Tooth discoloration is commonly found in the dental clinic and tooth bleaching has been considered the preferred esthetic alternative, being more conservative, safe and with predictable results. Supervised home-use of 10 percent Carbamide Peroxide (CP) bleaching with custom-trays is the most common bleaching procedure dispensed by dentists to their patients. The good results obtained with this technique stimulated the flourishing of new products and techniques. Over-the-counter (OTC) bleaching products appeared as a low-cost alternative to bleach discolored teeth without dentist supervision. Different OTC products are available in supermarkets, drug stores or on the Internet, including rinses, paint-on brushes, toothpastes, chewing guns, dental floss, and whitening strips. There is lack of clinical evidence regarding the safety and effectiveness of these products, being most of the studies supported by the manufacturers'. Basically, toothpastes, chewing gums, and dental floss are removal agents of superficial stains. Rinses and paint-on brushes with low levels of hydrogen peroxide have some whitening effect, but without clinical relevance. Strips present similar esthetic results and side-effects, compared to bleaching with 10 percent CP using trays; however, the studies have financial support from the manufacturers and were based on short term evaluations. Legislation varies widely in different countries regarding OTC dental bleaching. Concerns have appeared due to the potential abusive use of these self-medication agents, especially in young patients, with potential harmful results. Dentists should be acquainted with this kind of products to be able to inform their patients. In conclusion, there is a need for independent clinical trials to provide sufficient evidence regarding the use of OTC bleaching products.


Subject(s)
Humans , Dental Devices, Home Care/standards , Nonprescription Drugs/administration & dosage , Oxidants/administration & dosage , Peroxides/administration & dosage , Tooth Bleaching/standards , Urea/analogs & derivatives , Chewing Gum , Clinical Trials as Topic , Dental Devices, Home Care/economics , Dentifrices/administration & dosage , Hydrogen Peroxide/administration & dosage , Mouthwashes/administration & dosage , Nonprescription Drugs/adverse effects , Nonprescription Drugs/economics , Oxidants/adverse effects , Peroxides/adverse effects , Self Medication , Treatment Outcome , Toothpastes/administration & dosage , Urea/administration & dosage , Urea/adverse effects
18.
Ciênc. rural ; 38(4): 1172-1175, jul.-ago. 2008. ilus, tab
Article in Portuguese | LILACS | ID: lil-483458

ABSTRACT

Foram testadas 120 amostras séricas de cães com títulos (³100) perante Icterohaemorrhagiae para a determinação dos níveis séricos de uréia e de creatinina. Os animais com títulos ³800 apresentaram dosagens de uréia bastante superiores aos valores de referência e os com títulos ³200 e £400 apresentaram valores de uréia significativamente menores (P<0,05) do que os anteriores, porém ainda acima dos valores de referência. As amostras com títulos menores que 200 apresentaram dosagens de uréia significativamente menores (P<0,05) do que os observados nos outros grupos e dentro dos valores de referência. No que se refere à dosagem de creatinina sérica, verificou-se que apenas os animais com títulos ³800 apresentaram dosagens acima do padrão normal. Observou-se uma clara correlação entre dano renal e a sororreatividade específica para leptospirose.


One hundred and twenty serum samples from dogs with specific titres (³100) against Leptospira sp. serovar Icterohaemorrhagiae for the dosage of blood urea nitrogen (BUN) and creatinine levels were tested. Animals presenting titres ³800 showed BUN levels higher than reference values while samples with titres ³200 and £400 presented BUN levels significantly lower (P<0.05) than the others, but still higher than the reference values. Samples presenting titres lower than 200 showed BUN dosages according to the reference values. In relation to creatinine dosage, only samples presenting titres ³800 showed dosages higher than the reference values. A correlation between renal damage and specific seroreactivity for leptospirosis was demonstrated.


Subject(s)
Dogs , Creatinine/administration & dosage , Leptospirosis/veterinary , Urea/administration & dosage
19.
P. R. health sci. j ; 26(4): 367-372, Dec. 2007.
Article in English | LILACS | ID: lil-491641

ABSTRACT

OBJECTIVE: The purpose of this 14-day parallel, double blind clinical trial was to evaluate the tooth whitening efficacy of a 9% hydrogen peroxide gel (Colgate Visible White) relative to a 20% carbamide peroxide gel (Opalescence) positive control. METHODS: Forty-six consenting adults were randomly assigned to use one of the two products. All participants had 6 unrestored maxillary anterior teeth averaging a shade ranking score of 9 (A3) in the Vitapan Classical Shade Guide scale of 1 through 16 (lightest to darkest). Tooth whitening consisted of at-home 30-minute daily self-applications of the assigned product after brushing with a non-bleaching dentifrice. One of two calibrated examiners performed the baseline, 5-day, 7-day, and 14-day tooth shade evaluations for a given participant, utilizing the same Vita guide under unmodified color-corrected lighting conditions. Thirty-seven participants made all visits. Bleaching efficacy was measured with respect to mean shift (reduction from baseline) in rank scores of the maxillary anterior teeth, in which baseline rank scores functioned as covariables. RESULTS: Both treatment groups exhibited statistically significant mean shade rank score improvements from baseline after 5, 7, and 14 days at 3.14, 3.70 and 4.68 for Colgate Visible White and 1.60, 2.52 and 3.85 for Opalescence. CONCLUSIONS: Between-group comparison shows that while Colgate Visible White (9% hydrogen peroxide) provides a statistically significant tooth whitening improvement over Opalescence (20% carbamide peroxide) after 5 days of self-application, both products have a similar whitening effect after 7 and 14 days.


Subject(s)
Adult , Female , Humans , Male , Middle Aged , Tooth Bleaching/methods , Hydrogen Peroxide/administration & dosage , Peroxides/administration & dosage , Urea/analogs & derivatives , Double-Blind Method , Drug Combinations , Time Factors , Urea/administration & dosage
20.
Braz. oral res ; 21(2): 170-175, 2007. tab, graf
Article in English | LILACS | ID: lil-453198

ABSTRACT

Dental bleaching occurs due to an oxidation reaction between the bleaching agents and the macromolecules of pigments in the teeth. This reaction is unspecific and the peroxides can also affect the dental matrix causing mineral loss. On the other hand, recent studies have suggested that the thickener agent carbopol can also cause mineral loss. Thus, the objective of this study was to evaluate in vitro the effect of at-home dental bleaching on dental enamel microhardness after the use of bleaching agents with and without carbopol as a thickener agent. Bovine dental slabs with 3 x 3 x 3 mm were obtained, sequentially polished, and randomly divided into 4 groups according to the experimental treatment: G1: 2 percent carbopol; G2: 10 percent carbamide peroxide with carbopol; G3: carbowax; G4: 10 percent carbamide peroxide with poloxamer. Bleaching was performed daily for 4 weeks, immersed in artificial saliva. Enamel microhardness values were obtained before the treatment (T0) and 7 (T1), 14 (T2), 21 (T3), 28 (T4), and 42 (T5) days after the beginning of the treatment. ANOVA and Tukey's test revealed statistically significant differences only for the factor Time (F = 5.48; p < 0.01). All bleaching and thickener agents caused no alterations on the enamel microhardness.


O clareamento dental ocorre devido a uma reação de oxidação entre o agente clareador e as macromoléculas de pigmentos presentes nos dentes. Esta reação é inespecífica e o peróxido pode agir na matriz dental causando perdas de mineral. Por outro lado, estudos recentes sugerem que o agente espessante carbopol também pode causar perda mineral. Assim, o objetivo deste trabalho foi avaliar in vitro o efeito do clareamento caseiro sobre a microdureza do esmalte após o uso de agentes clareadores com e sem carbopol como espessante. Fragmentos de esmalte bovino de 3 x 3 x 3 mm foram obtidos, polidos seqüencialmente e aleatoriamente divididos em 4 grupos de acordo com o tratamento experimental: G1: carbopol a 2 por cento; G2: peróxido de carbamida a 10 por cento com carbopol; G3: carbowax; G4: peróxido de carbamida a 10 por cento com poloxamer. O clareamento foi realizado diariamente por 4 semanas em saliva artificial. A microdureza do esmalte foi avaliada antes (T0) e após 7 (T1), 14 (T2), 21 (T3), 28 (T4), e 42 (T5) dias do início do tratamento. A ANOVA e o teste de Tukey revelaram diferenças estatísticas significantes somente para o fator Tempo (F = 5,48; p < 0,01). Os agentes clareadores e espessantes não causaram alterações na microdureza do esmalte.


Subject(s)
Animals , Cattle , Dental Enamel/drug effects , Oxidants/administration & dosage , Peroxides/administration & dosage , Polyvinyls/administration & dosage , Tooth Bleaching/methods , Urea/analogs & derivatives , Dental Devices, Home Care , Drug Combinations , Drug Evaluation, Preclinical , Hardness Tests , Hardness/drug effects , Random Allocation , Tooth Bleaching/adverse effects , Urea/administration & dosage
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