387 resultados para Peróxido de Carbamida


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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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Dental tooth bleaching is a conservative option for the treatment of tooth stains. It is based on the use of hydrogen peroxide as an active agent. Despite its effectiveness to lighten tooth colour, there is concern regarding its use due to the effects it could have over enamel surface. There is scarce evidence on the subject and contradictions exist between different authors. The aim of this study was to compare enamel surface micromorphology after bleaching teeth with different concentrations of hydrogen peroxide solutions. Method: 50 healthy bovine incisors sectioned horizontally at the cemento-enamel junction were prepared. Contents of pulp chamber and tooth surfaces were cleaned. The buccal surface of each tooth was divided vertically, assigning one half to the control group (CG) and the other randomly to: Group 1: 25 samples treated with 15% hydrogen peroxide with nitrogen doped titanium dioxide. Group 2: 25 samples treated with 35% hydrogen peroxide. Square samples (2x2 mm.) were obtained and observed by SEM (magnification of 5.000x and 10.000x). Results: All treated groups showed longitudinal depressions on the surface and increased surface roughness. Conclusions: Tooth bleaching with hydrogen peroxide produces subclinical alterations over bovine enamel surface. 15% hydrogen peroxide bleaching agent produced less micromorphology alteration over bovine enamel surface than the 35% hydrogen peroxide agent.

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Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

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Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

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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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Using the sol-gel process, organic-inorganic hybrid coatings were synthesized by incorporation of different concentrations of functionalized carbon nanotubes, to improve their mechanical strength and thermal resistance without changing its passivation character. The siloxane-PMMA hybrids were prepared by radical polymerization of methyl methacrylate (MMA) with 3-methacryloxipropiltrimethoxisilane (MPTS) using the thermal initiator benzoyl peroxide (BPO), followed by acid catalyzed hydrolysis and condensation of tetraethoxysilane (TEOS). The analysis of pristine and functionalized carbon nanotubes was carried out using Scanning Electron Microscopy, X-ray Photoelectron Spectroscopy and Raman Spectroscopy. Structural analysis of hybrids was performed by Nuclear Magnetic Resonance, Atomic Force Microscopy and Raman Spectroscopy. For analysis of mechanical strength and thermal stability were performed mechanical compression tests and thermogravimetric analysis, respectively. Electrochemical Impedance Spectroscopy was used to evaluate the corrosion resistance in saline environment. The results showed an effective functionalization of carbon nanotubes with carboxyl groups and conservation of its structure. The hybrids showed high siloxane network connectivity and roughness of approximately 0.3 nm. The incorporation of carbon nanotubes in the hybrid matrix did not change significantly their thermal stability. Samples containing carbon nanotubes exhibit good corrosion resistance (on the order of MΩ in saline environment), but the lack of complete dispersion of carbon nanotubes in the hybrid, resulted in a loss of mechanical and corrosion resistance compared to hybrid matrix.

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Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

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Risk of mechanical injuries contraindicate brushing and elect chemical agents as appropriate for daily cleaning of dentures relined with resilient materials. It was evaluated the effect of denture cleansers on the wettability of denture relining material (Dentusoft, Dental Medrano). We used 20 discs of acrylic resin thermoactivated VipiCril ® with 30mm diameter and 4mm thick, covered by 2mm Dentusoft ®. Divided into 4grupos were stored in artificial saliva at 37 +1 º C for 30 days, immersed daily for 15minutes in distilled water (GI), Corega ® Tabs (GII), a solution of sodium bicarbonate (GIII) or solution of sodium hypochlorite (GIV) after which, on the soft liner were poured 2 ml of type IV gypsum (Durone IV, Dentsply). Reached the final setting of the gypsum specimens were sectioned vertically and medially, settled water with sandpaper No. 400 and mounted on suitable device for reading (in the right and left) of the contact angle Carl Zeiss microscope (precision, 001). The results were submitted to analysis, showed non-normal distribution, opting for non-parametric test. Kruskal Wallis test performed at 5% significance, there was statistical difference between the groups with lower average contact angle for GII. It was concluded that the chemical cleaning Corega Tabs ® allowed a better adaptation of relining the gypsum studied.

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Esse trabalho teve como objetivo avaliar, clinicamente, a efetividade de dois agentes clareadores aplicados sobre a superfície dentária durante 45 minutos, sem troca do gel. Foram selecionados 10 pacientes de acordo com os critérios de inclusão e exclusão, e a arcada superior dos pacientes foi dividida em duas hemiarcadas (n = 10): na hemiarcada direita (HD), foi aplicado o peróxido de hidrogênio a 35% (PH) Clàriant Office (Angelus); e, na hemiarcada esquerda (HE), o PH 38% Opalescence Boost (Ultradent). Foram realizadas duas sessões clínicas, de 45 minutos cada, com intervalo de uma semana entre as sessões. Inicialmente, ao tratamento clareador, os pacientes receberam profilaxia, moldagem para guia de mensuração de cor com silicone de condensação e avaliação de cor por meio de um aparelho espectrofotômetro Vita Easyshade (Vita Zhanfabrik, Alemanha). Após 14 dias do término do tratamento clareador, foi realizada a mensuração final da cor dos dentes. Os dados foram submetidos ao teste t e de Tukey (p < 0,05). Os resultados demonstraram não haver diferença estatisticamente significativa entre as hemiarcadas quanto à efetividade do clareamento (p = 0,146) e nem quanto à sensibilidade. Pode-se concluir que a aplicação dos materiais avaliados sem troca do gel, por 45 minutos, foi eficaz em promover o clareamento de dentes vitais e com baixa sensibilidade dentária.

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Tooth bleaching is the most common treatment and more conservative to get a smile with white teeth. However, the tooth sensitivity has been a major adverse effects caused by this treatment, which raises questions about the effect of bleaching the pulp. Therefore, we performed a literature review in order to study the relationship between bleaching agents and their possible effects on the dental pulp. We review various articles showing that the peroxide compound used to whiten teeth, penetrates through enamel and dentin until the pulp chamber causing changes of variable intensity or induce pulp necrosis. Moreover, we found that the higher the concentration of peroxide in the bleaching agent, and the greater the contact time with this dental structure, the greater the damage caused in the pulp. Although several studies show that the bleaching agent hydrogen peroxide-based pulp can make changes, there are still many gaps to be filled.

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This study aimed to evaluate the clinical effectiveness of two bleaching agents without changing the whitening gel during the clinic session 1X45minutos. 10 patients were selected according to the criteria of inclusion and exclusion and upper arch of the patients were divided into two quadrants (n: 10), G1: gel clareador Clàriant Office (hidrogênio35 Angellus) peroxide% (PH) in superior right side (LD) and the gel WhitenessHp Blue (FGM) PH 35% on the superior left side (LE. 2 clinical sessions were accomplished, 45 minutes each, with an interval of one week between sessions. At first the bleaching treatment patients received prophylaxis, molding to guide measurement of color with condensation silicon and the color evaluation through the apparel spectrophotometer VITA Easyshade (Vita Zhanfabrik, Alemanhã). 14 days after the end of the bleaching treatment was performed the measurement final color of the teeth. The patients reported sensitivity in scale 0-4. The result showed that through T Test comparing quadrants presented no statistical differences (p>0,05) in relation to coloration and dental sensibility. It can be concluded that the materials evaluated are effective for bleaching vital teeth with low tooth sensibility.

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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)