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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
1

Efeito do tratamento t?rmico do tit?nio sobre a prolifera??o de c?lulas pr?-osteobl?sticas

Macedo, Haroldo Reis Alves de 20 August 2008 (has links)
Made available in DSpace on 2014-12-17T14:06:48Z (GMT). No. of bitstreams: 1 HaroldoRAM.pdf: 1140599 bytes, checksum: 95a046b646a7cfa0d6cf0153f138783f (MD5) Previous issue date: 2008-08-20 / Conselho Nacional de Desenvolvimento Cient?fico e Tecnol?gico / Titanium is a biomaterial widely employed in biomedical applications (implants, prostheses, valves, stents). Several heat treatments are usually used in order to obtain physical properties required to different applications. This work studied the influence of the heat treatment on microstructure of commercial pure titanium, and their consequences in growth and proliferation of MC3T3-E1 cells. Discs of titanium were treated in different temperatures, and characterized by optical microscopy, image analysis, wettabillity, roughness, hardness and X-ray diffraction. After the heat treatment, significant modifications in these properties were observed. Pattern images of titanium, before and after the cell culture, were compared by overlapping to analyze the influence of microstructure in microstructure and preferences guidance cells. However, in general, titanium discs that showed a higher residual strength also presented an increase of cells numbers on surface / O tit?nio como biomaterial ? amplamente utilizado em dispositivos biom?dicos (implantes, pr?teses, v?lvulas, stents entre outros). Diversos tratamentos t?rmicos s?o usualmente utilizados na obten??o das propriedades necess?rias para as diferentes aplica??es. Este trabalho estudou a influ?ncia desses tratamentos na microestrutura do tit?nio comercialmente puro e suas conseq??ncias no crescimento, forma e prolifera??o de c?lulas pr?-osteobl?stica. Para tanto foram utilizados discos de tit?nio submetidos a diferentes tratamentos e caracterizados por microscopia ?tica, an?lise de imagens, molhabilidade, rugosidade, dureza e difra??o de raios-X. Ap?s os tratamentos t?rmicos foram verificado modifica??es significantes nestas propriedades. Padr?es de imagens de superf?cies do tit?nio antes e ap?s a cultura de c?lula foram comparados atrav?s de sobreposi??o para analisar a influ?ncia da microestrutura na resposta biol?gica, n?o sendo verificadas correla??es entre a microestrutura e as prefer?ncias orientacionais das c?lulas. Entretanto de um modo geral verificou-se que os discos que presentaram maior estado de tens?o residual apresentaram tamb?m maior n?mero de c?lulas em sua superf?cie
2

Tratamento t?rmico do tit?nio e suas consequ?ncias sobre as propriedades f?sico-qu?micas e de biocompatibilidade

Macedo, Haroldo Reis Alves de 03 February 2012 (has links)
Made available in DSpace on 2014-12-17T14:07:09Z (GMT). No. of bitstreams: 1 HaroldoRAM_TESE.pdf: 4102900 bytes, checksum: e74f8a9122bb5cd84cbeadae3a476ce1 (MD5) Previous issue date: 2012-02-03 / Conselho Nacional de Desenvolvimento Cient?fico e Tecnol?gico / The titanium and titanium alloys are widely used as biomaterial in biomedical device and so research have been developed aiming to improve and/or better to understand interaction biomaterial/biological environment. The process for manufacturing of this titanium implants usually involves a series of thermal and mechanical processes which have consequence on the final product. The heat treatments are usually used to obtain different properties for each application. In order to understand the influence of these treatments on the biological response of the surface, it was done, in this work, different heat treatments in titanium and analyzed their influence on the morphology, adhesion and proliferation of the pre-osteoblastic cells (MC3T3-E1). For such heat-treated titanium disks were characterized by optical microscopy, contact angle, surface energy, roughness, microhardness, X-ray diffraction and scanning through the techniques (BSE, EDS and EBSD). For the analysis of biological response were tested by MTT proliferation, adhesion by crystal violet and β1 integrin expression by flow cytometry. It was found that the presence of a microstructure very orderly, defined by a chemical attack, cells tend to stretch in the same direction of orientation of the material microstructure. When this order does not happen, the most important factor influencing cell proliferation is the residual stress, indicated by the hardness of the material. This way the disks with the highest level state of residual stress also showed increased cell proliferation / O tit?nio e suas ligas s?o amplamente utilizados como biomaterial em dispositivos biom?dicos e devido a isso pesquisas t?m sido desenvolvidas visando aperfei?oar e/ou compreender melhor a intera??o biomaterial/meio biol?gico. O processo de fabrica??o desses dispositivos de tit?nio geralmente envolve uma s?rie de processos t?rmicos e mec?nicos e que t?m consequ?ncias no produto final. Os tratamentos t?rmicos s?o usualmente utilizados para obten??o de propriedades diferenciadas para cada aplica??o. Com o intuito de entender a influ?ncia desses tratamentos sobre a resposta biol?gica da superf?cie, foram realizados, no presente trabalho, diferentes tratamentos t?rmicos em tit?nio e analisadas suas influ?ncias na morfologia, ades?o e prolifera??o de c?lulas pr?-osteobl?stica (MC3T3-E1). Para tanto os discos de tit?nio tratados termicamente foram caracterizados por microscopia ?tica, ?ngulo de contato, energia de superf?cie, rugosidade, microdureza Vickers, difra??o de raios-X e microscopia eletr?nica de varredura atrav?s das t?cnicas de EBS, EDS e EBSD. Para an?lise da resposta biol?gica foram realizados teste de prolifera??o por MTT, ades?o por cristal violeta e express?o da integrina β1 por citometria de fluxo. Foi verificado que na presen?a de uma microestrutura muito ordenada, definida atrav?s de um ataque qu?mico, as c?lulas tendem a se alongar no mesmo sentido da orienta??o microestrutural do material. Quando essa ordem n?o acontece, o fator mais importante a influenciar na prolifera??o celular ? a tens?o residual, indicada pela dureza do material. Deste modo os discos que apresentaram maior estado de tens?o residual apresentaram tamb?m maior prolifera??o celular

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