371 resultados para die surface treatment


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Objectives. To compare three different designs for measuring the bond strength between Y-TZP ceramic and a composite material, before and after ceramic surface treatment, evaluating the influence of the size of the adhesive interface for each design.Methods. 'Macro'tensile, microtensile, 'macro'shear, microshear, 'macro'push-out, and micropush-out tests were carried out. Two Y-TZP surface treatments were evaluated: silanization (sil) and tribochemical silica coating (30 mu m silica-modified Al2O3 particles + silanization) (TBS). Failure mode analysis of tested samples was also performed. Results. Both the surface treatment and the size of the bonded interface significantly affected the results (p = 0.00). Regardless of the type of surface treatment, the microtensile and microshear tests had higher values than their equivalent "macro" tests. However, the push-out test showed the highest values for the "macro" test. The tensile tests showed the greatest variability in results. The tribochemical silica coating method significantly increased bond strength for all tests.Significance. Different test designs can change the outcome for Y-TZP/cement interfaces, in terms of mean values and reliability (variability). The 'micro'tests expressed higher bond strengths than their equivalent 'macro'tests, with the exception of the push-out test (macro > micro). (C) 2015 Academy of Dental Materials. Published by Elsevier Ltd. All rights reserved.

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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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The short dental implants represent an option of previsible treatment, its main indication lives in the possibility of avoiding techniques surgical invasive. The literature in the display that the geometry of the implants is of vital importance, combined with wide diameters and surface treatment, mainly when the bone quality is unfavorable. The mechanical resistance can be enlarged, increasing the number of implants and being used the spliting among them. A rigorous protocol prosthodontist should be following with intention of to avoid oblique loads and to control habits parafuncionais. We aimed at to discuss, through a wide bibliographical revision the short dental implants, their characteristics and indications, giving emphasis to the aspects biomechanic of the same ones. Material and Method: The bases given: Pubmed, ISI and Dentistry Oral Science from 1990 to 2009, were consulted to identify researches related to the length of the dental implants, with emphasis to the considered short and the biomechanics related to the same ones. They were located 568 articles, being selected 69 that gathered the inclusion criteria. Result: Among these 69 selected, 26 articles agreed the evidence level. Conclusion: Inside of the limits of appraised data, it can be concluded that the short implants represent a good treatment alternative, especially for cases with reduced bone bed. However a rigorous indication protocol and use should be followed for warranty of the success of the treatment.

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Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

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Pós-graduação em Odontologia Restauradora - ICT

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Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

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

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Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

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Surface treatments have been used to modify the surface of titanium alloys. The purpose of this study is to evaluate the surface of Ti-30Ta alloy after biomimetic approach associated to antibiotic incorporation. The ingots were obtained in arc melting furnace, treated and cold-worked by swaging. The surface treatment was performed in two steps: biomimetic treatment and antibiotic incorporation. For biomimetic treatment, first an alkaline treatment (NaOH 1M at 60ºC) was performed, followed by heat treatment and immersion in SBFx5 (Simulated Body Fluid) for a period of 24 hours. In order to incorporate the antibiotic, samples were immersed in a solution formed by drugs plus SBFx5 for 48 hours. The sample surfaces were analyzed by scanning electron microscopy (SEM), X-Ray diffraction (XRD), atomic force microscopy (AFM) and contact angle measurements. The release of antibiotic from coated implants was measured in phosphate buffer saline at pH 7.4 by using UV/VIS spectrometry. Results have shown changes on the surface after incorporating the drug, which is gradually co-precipitated with the Ca-P crystals, forming a uniform and rough layer on the metal surface

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The time elapsed between a trauma and tooth replantation usually ranges from 1 to 4 h. The chances of root surface damage are higher when tooth replantation is not performed immediately or if the avulsed tooth is not stored in an adequate medium. This invariably leads to necrosis of pulp tissue, periodontal ligament cells and cementum, thus increasing the possibility of root resorption, which is the main cause of loss of replanted teeth. This paper presents a comprehensive review of literature on root surface treatments performed in cases of delayed tooth replantation with necrotic cemental periodontal ligament. Journal articles retrieved from PubMed/MedLine, Bireme and Scielo databases were reviewed. It was observed that, when there are no periodontal ligament remnants and contamination is under control, replacement resorption and ankylosis are the best results and that, although these events will end up leading to tooth loss, this will happen slowly with no loss of the alveolar ridge height, which is important for future prosthesis planning.

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The surface properties of boron-doped nanocrystalline diamond films treated with H(2) plasma was investigated in regard to their electrochemical response for phenol oxidation. The surface of these films is relatively flat formed by crystallites with sizes of about 40 nm. X-ray photoelectron spectroscopy analyses showed that electrode surface has a high amount of C-H bonds. This behavior is in agreement with Mott-Schottky plot measurements concerning the flat band potential that presented a value as expected for hydrogenated diamond surface. This electrode presented the phenol detection limit of 0.08 mg L(-1) for low phenol concentrations from 40 to 250 mu mol L(-1).

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Restorative dentistry has been increasingly concerned with preservation of the dental structure. For that reason, ultraconservative cavity preparations have been performed with air abrasion systems. The aim of this study was to present treatment options for the occlusal surface of first permanent molars with employment of the conventional method and the air abrasion system for accomplishment of the cavity preparation and a composite occlusal matrix for an accurate reproduction of the tooth surface.

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The purpose of this study was to evaluate the surface roughness of four conventional chemically cured glass ionomer cements (Fuji IX, Ketac Molar, Vidrion R and Vitromolar) commonly used in atraumatic restorative treatment (ART) immediately after material preparation. Twenty specimens of each glass ionomer cement were fabricated and surface roughness was measured after material setting. The specimens were further examined under scanning electron microscopy. Data were analyzed statistically by Kruskal-Wallis test and Mann-Whitney test at 5% significance level. Two-by-two comparisons showed statistically significant difference (p<0.05) between all materials, except for Ketac Molar and Vidrion R, which had statically similar results (p>0.05). Regarding their results of surface roughness, the materials can be presented in a crescent order, as follows: Ketac Molar < Vidrion R < Fuji IX < Vitromolar. In conclusion, from the tested glass ionomer cements, Fuji IX, Ketac Molar and Vidrion R presented acceptable surface roughness after setting reaction while Vitromolar showed remarkably higher surface roughness.