986 resultados para Color changes


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Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

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Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

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Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

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Pós-graduação em Ciências Odontológicas - FOAR

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Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

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Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

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The increasing interest of patients for a better aesthetic appearance of their smile, associated with the development of new materials and techniques, encouraged by media couverage of this concept of beauty, provided an important evolution of cosmetic dentistry. As the darkness of a single anterior tooth or a group of teeth, in most cases, impairs the appearance of the smile and there is growing appreciation of the less invasive procedures, the technique of tooth bleaching is an important option for aesthetic treatment. To have success in the bleaching treatment, it is important to have knowledge of the origin, nature and composition of the stain. Among the causes of color changes acquired post-eruptive, dental trauma, with or without pulp necrosis, is one of the most commonly encountered etiologies, characterized by a reddish-brown color. Current techniques of bleaching for teeth treated endodontically employ oxidative agent hydrogen peroxide. The objective of this paper is to describe the immediate technique of bleaching non-vital tooth by presenting a clinical case.

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The purpose of this study was to evaluate the compressive strength and color changes of one composite resin modified by TiO2 nanoparticles and their distribution by SEM.

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In-office dental bleaching has been subject of several studies. Generally those studies quantify through visual analysis, the shade reduction of the teeth submitted to different bleaching protocols (light sources, bleaching agent concentrations and irradiation time). The objective of this work is the determination of the influence of four irradiation protocols on the obtainment of better aesthetic results using a colorimetric spectrophotometer that quantifies color changes in each situation imposed. Forty bovine incisors were selected in function of similar anatomic characteristics; a concentrated coffee solution was used to stain the teeth. A commercial spectrophotometer was used to measure the color changes during evolution of the experiment (stain and bleaching phases) and the obtained data was analyzed by the ANOVA test. The obtained data showed the evolution of teeth color during the staining period, as well as, the color reduction that each bleaching protocol achieved. Based on our findings it is possible to conclude that bleaching protocols with larger irradiation periods did not showed significant differences when compared with shorter irradiation protocols, in that way the use of protocols with 30 min or more of consecutive irradiation are not clinically justified and also can cause several side effects.

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Introduction: One of the violence types more observed against children is the physical abuse, which produces many types of traumatic injuries. Contusions are common trauma signs and may indicate aggression when frequently present in locations where accidental injuries are rare. Contusions in skin undergo color changes with the passage of time, and such change in color is called “spectrum of bruise colors of Legrand du Saulle”. Thus, it is possible to estimate the age of the lesion based on the evaluation of color. Injuries caused by child abuse often reach regions of head, face and neck, because they are exposed and easily accessible. Therefore, the dentist is responsible with regard to the diagnosis and the actions to be undertaken against the cases of child abuse. Objective: To present and discuss the significance of the spectrum of bruise colors as a considerable visible trace in suspicion of violence against children and adolescents, during dentists’ clinical routine. Literature review: The study of the “spectrum of bruise colors of Legrand du Saulle” refers to the estimation of the age of the injury, in respect to the color change. The application of this study is of great value for identify if a lesion occurred from a single incident or from multiple incidents, especially in cases where it occurs in the same region of the body, indicative of repetitive trauma. Conclusion: The spectrum of bruise colors is very important for health professionals, such as dentists, for the identification or suspicion of cases of abuse against children and adolescents. As great part of the lesions originated of abuse involve the areas of head and neck, it is unacceptable that these professionals are unaware of the basic signs to help in early diagnosis, which is the case of the colors of the lesions. However, concerning the chronology of the spectrum of bruise colors, it is not possible to establish rigorous times.

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Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

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Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

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The objective was to evaluate the effect of thermocycling on the color variation of three different composite resins . We studied was Resin Enamel on 3 levels : ( Esthetic X , Opallis and Venus ) ; Resin Dentin in three levels : ( Esthetic X , Opallis and Venus ) and Thermocycling on level 1 : ( 3,000 cycles ) ; variable was the change of color gauged by spectrophotometry . 60 specimens , subdivided into 6 groups were made : GI - Esthetic X Enamel ; GII - Esthetic X dentin ; GIII - Opallis Enamel ; GIV - Opallis dentin ; GV - Enamel and GVI Venus - Venus dentin . The specimens were prepared with a matrix to standardize samples . The inserts of incrementally resins and polymerized with a halogen light Ultralux unit ( Dabi Atlante , Brazil ) with a power of 450mW / cm ² . After fabrication , underwent color reading with a UV Visible Spectrophotometer reflection , UV -2450 ( Shimadzu , Kyoto , Japan ) , with the changes calculated by the system CIE L * a * b * . Then isolates were stored in artificial saliva at 35 ° C ± 2 ° C during 3 months containers being subjected to the effects of thermal cycling for 3000 cycles over the range of 5C to 55C . Again subjected to chromatic evaluation. For the analysis of the results of color change of the studied resins was applied ANOVA two factors at 5 % . The results showed a statistically equal resins enamel GI and GV ( p = 0.79 ) ; the same was not observed for GI and G III resins , where the color change was higher for resin G III ( p = 0.0000002 ) . The same was observed between G III and GV , where the resin enamel G III showed a statistically superior to the color change ( p = 0.0000005 ) Average . Resins to dentin was there a statistical equality between the materials studied . We conclude that the resins studied change in color and resin enamel G III was the most suffered major color changes after aging by thermocycling .