Thesis (M.S.)--University of Michigan, 2003. / Includes bibliographical references.

Thesis (doctoral)--Umeå University, Sweden, 1996. / Added t.p. with thesis statement inserted. Includes bibliographical references.

Thesis (M.S.)--University of Michigan, Ann Arbor, 1983. / Typescript (photocopy). eContent provider-neutral record in process. Description based on print version record. Includes bibliographical references (leaves 55-61).

Thesis (M.S.)--University of Michigan, 1968.

Thesis (doctoral)--Umeå University, Sweden, 1996. / Added t.p. with thesis statement inserted. Includes bibliographical references.

Thesis (M.D.S.)--University of Hong Kong, 2003. / Also available in print.

Thesis (Ph. D.)--University of Hong Kong, 2005.

Made available in DSpace on 2014-06-11T19:31:33Z (GMT). No. of bitstreams: 0 Previous issue date: 2008-09-23Bitstream added on 2014-06-13T21:02:45Z : No. of bitstreams: 1 camara_as_dr_arafo.pdf: 5289887 bytes, checksum: 3a5ed5f15b899e42e09e2c3b3c5aa9f3 (MD5) / Universidade Estadual Paulista (UNESP) / O presente trabalho se propôs a avaliar as alterações geométricas e dimensionais dos instrumentos de NiTi do sistema ProTaper Universal em relação ao sistema ProTaper, bem como o efeito destas sobre a flexibilidade e a resistência à torção dos instrumentos. Um total de 298 instrumentos foram empregados neste estudo. Inicialmente, 12 instrumentos de cada tipo dos dois sistemas foram submetidos a uma caracterização geométrica e dimensional por microscopia óptica. Foram avaliados os parâmetros ângulo, comprimento e diâmetro de ponta, comprimento de cada pitch ao longo das hastes e diâmetro do instrumento a cada milímetro da ponta. Além disso, a área da secção transversal destes instrumentos a 3mm a partir da ponta foi determinada em imagens obtidas por microscopia eletrônica de varredura, usando 01 instrumento de cada formato. Após isto, todos os instrumentos foram aleatoriamente divididos em 4 grupos distintos: Grupo 1 contendo 60 instrumentos ProTaper S1, S2, F1, F2 e F3, sendo 12 unidades de cada formato para os ensaios de torção; Grupo 2 contendo 60 instrumentos ProTaper S1, S2, F1, F2 e F3, sendo 12 unidades de cada formato para os ensaios de flexibilidade; Grupo 3 contendo 84 instrumentos ProTaper Universal S1, S2, F1, F2, F3, F4 e F5, sendo 12 unidades de cada formato para os ensaios de torção; Grupo 4 contendo 84 instrumentos ProTaper S1, S2, F1, F2, F3, F4 e F5, sendo 12 unidades de cada formato para os ensaios de flexibilidade. Tais ensaios de torção e flexibilidade foram executados de acordo com a especificação ISO 3630-1 em um dispositivo de bancada para testes utilizando um programa para aquisição e processamento dos dados especialmente desenvolvido para este fim. Os valores para torque máximo, deflexão angular até a fratura e momento de dobramento foram analisados estatisticamente pelo teste... / The present study has proposed to evaluate the instruments structural changes from NiTi ProTaper System to NiTi ProTaper Universal System as well this effect over torsional resistance and flexibility. It was used a total amount of 298 instruments. At the beginning, 12 instruments of each size from both systems were analyzed dimensional and geometrically by optical microscopy under parameters of angle, length and tip diameter, pitch’s length along the blade and instrument’s diameter from tip until the end of the active part. Besides, one sample of each size had its 3-mm from the tip’s cross sectional area calculated under SEM images. After that, all the instruments were randomly divided into 4 different groups: Group 1 having 60 ProTaper instruments inside (S1, S2, F1, F2 and F3),12 samples from each size, to be submitted to torsion test; Group 2 having 60 ProTaper instruments inside (S1, S2, F1, F2 and F3),12 samples from each size, to be submitted to bending test; Group 3 having 84 ProTaper Universal instruments inside (S1, S2, F1, F2, F3, F4 and F5),12 samples from each size, to be submitted to torsion test; Group 4 having 84 ProTaper instruments inside (S1, S2, F1, F2, F3, F4 and F5),12 samples from each size, to be submitted to bending test. These torsion and bending tests were performed using a bench test device connected with a software to acquire and process data specially developed to this purpose, according to ISO 3630-1. Maximum torque, angular deflection until fracture and bending moment values were statistically analysed using Student’s t test. The results have shown that ProTaper and ProTaper Universal system’s instruments presented good geometric standardization and acceptable surface features, however differences were detected among the systems. The maximum torque and the bending moment at 45º. were higher for instruments... (Complete abstract click electronic access below)

Made available in DSpace on 2015-03-03T11:52:28Z (GMT). No. of bitstreams: 0 Previous issue date: 2014-03-18Bitstream added on 2015-03-03T12:06:42Z : No. of bitstreams: 1 000806171_20170318.pdf: 373565 bytes, checksum: 5ce6c6c668fd43fb2dedbc628f0df470 (MD5) Bitstreams deleted on 2017-03-24T12:04:48Z: 000806171_20170318.pdf,. Added 1 bitstream(s) on 2017-03-24T12:05:39Z : No. of bitstreams: 1 000806171.pdf: 683941 bytes, checksum: 81746304f12352e2fe58184ac5b1059e (MD5) / Avaliar os efeitos da incorporação do iodofórmio ou do hidróxido de cál-cio (HC) respectivamente no cimento Sealer 26 ou MTA Fillapex (MF). Na ava-liação com o Sealer 26, as proporções de 1.1g, 0,55g or 0.275g foram incorpo-radas ao cimento e o de tempo de presa, escoamento, solubilidade, pH e libe-ração de cálcio foram avaliados. Na análise do MF puro, acrescido de 5% (MF5) ou 10%(MF10) em massa de HC, o escoamento, pH e liberação de cál-cio foram comparados com AH Plus. A adição do iodofórmio ao Sealer26 au-mentou o tempo de presa do cimento (p<0,05), mas os demais resultados fo-ram similares (p>0,05). Em 24hs, a mistura com 1.1g: 0.55g de iodofórmio de-monstrou menor pH que o cimento puro (p<0,05). O MF teve maior escoamento que os demais cimentos (p<0,05). O MF10 apresentou menor escoamento que MF (P<0,05). O MF10 apresentou maior pH que o AH Plus (p<0,05).A liberação de cálcio foi similar ao MF e o MF10 (p>0,05). O MF5 demonstrou menor esco-amento que o MF e maior que MF10 (p<0,05), tendo maior valor de pH que o MF (p<0,05) e similar liberação de cácio ao MF10. A adição do iodofórmio inter-fere no tempo de presa e solubilidade do Sealer 26 e a adição de 5%HC no MF apresentou-se como alternativa para reduzir o escoamento, sem interferir no potencial de alcalinização do MF. / To evaluate the effects of incorporation of iodoform or calcium hydroxide (CH) respectively in cement Sealer 26 or MTA Fillapex (MF) . In review with the Sealer26, the proportions of 1.1g, 0.55g or 0.275g were incorporated into the cement and the setting time, flow, solubility, pH and calcium release were evaluated. The analysis of pure MTA Fillapex (MF) or containing 5% (MF5) or 10% (MF 10) calcium hydroxide (CH), in weight, in comparison with AH Plus sealer .The addition of iodoform to Sealer26 cement increased setting time(p < 0.05), but the other results were similar (p> 0.05). In 24 hours, the mixture with 1.1g : 0.55g iodoform showed lower pH than the pure cement ( p < 0.05 ) . The MF had greater flow than the other cements ( p < 0.05 ) . The MF10 showed lower flow that MF ( P < 0.05 ) . The MF10 showed pH greater than AH Plus (p < 0.05). Calcium realise was similar to MF and MF10 (p> 0.05). The MF5 showed less than the flow MF , and greater than MF10 (p <0.05 ), and higher pH value than the MF (p <0.05) and calcium release similar to MF10 . The addi-tion of iodoform interferes with the setting time and solubility of Sealer 26 and the addition of 5% CH in the MF presented as an alternative to reduce the flow without interfering with potential alkalization.

Made available in DSpace on 2014-06-11T19:24:37Z (GMT). No. of bitstreams: 0 Previous issue date: 2011-03-31Bitstream added on 2014-06-13T19:52:06Z : No. of bitstreams: 1 cornelio_alg_me_arafo.pdf: 397515 bytes, checksum: b29bef30bd070aadb818ff553343600a (MD5) / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES) / A proposta deste estudo foi investigar a citotoxicidade, ação antimicrobiana e pH do cimento Portland puro (CP) e associações com agentes radiopacificadores: óxido de bismuto (CPBi), óxido de zircônio (CPZir), tungstato de cálcio (CPCa). Para avaliar o potencial citotóxico, foram empregadas linhagens celulares de fibroblastos do ligamento periodontal de camundongos (mPDL) e osteosarcoma de ratos (ROS 17/2.8). Ambas foram expostas por 24 horas a diferentes concentrações do CP fresco, CP associado com radiopacificadores e cimento de óxido de zinco eugenol. Peróxido de hidrogênio foi aplicado como controle positivo para apoptose. A viabilidade após incubação com os cimentos foi avaliada pela atividade da enzima desidrogenase mitocondrial. A morfologia celular foi analisada microscopicamente pelo corante violeta de cresilo, e o mecanismo de morte celular foi determinado pela metodologia de laranja de acridina/brometo de etídio. Os dados foram analisados estatisticamente por ANOVA e Tukey post-test (p<0.01). A correlação entre os dois tipos de morte celular e valores de pH foi estabelecido pela correlação linear de Pearson. O ensaio da enzima desidrogenase mitocondrial revelou um padrão significante de morte celular apenas nas altas concentrações dos eluídos de cimento. CP puro não foi citotóxico, mesmo na alta concentração de 100mg/ml. As imagens microscópicas mostraram que nenhuma das formulações de CP causaram danos as linhagens celulares. Análises estatísticas dos dados de apoptose/necrose demonstram que CP e CP mais agentes radiopacificadores promoveram morte por necrose estatisticamente significativa apenas em 100mg/ml. Os resultados mostraram que CP associado com óxido de bismuto, óxido de zircônio ou tungstato de cálcio não foram citotóxicos para mPDL ou ROS 17/2.8, e podem ser boas... / The purpose of this study was to investigate the cytotoxicity, antimicrobial and pH of pure Portland cement (PC), and associations with radiopacifier agents: bismuth oxide (CPBi), zirconium oxide (CPZir), calcium tungstate (CPCA). To assess the potential cytotoxicity, fibroblast cell lines from the periodontal ligament of mice (mPDL) and rat osteosarcoma (ROS 17/2.8) were used. Both were exposed for 24 hours with different concentrations of fresh PC, PC associated with radiopacifiers and eugenol zinc oxide cement. Hydrogen peroxide was used as a positive control for apoptosis. The viability after incubation with the cements was evaluated by mitochondrial dehydrogenase enzyme activity. Cell morphology was examined microscopically by cresyl violet stain, and the mechanism of cell death was determined by the method of acridine orange / ethidium bromide. The data were statistically analyzed by ANOVA and Tukey post-test (p <0.01). The correlation between the two types of cell death and pH values was established by Pearson linear correlation. The mitochondrial dehydrogenase enzyme assay revealed a significant pattern of cell death only at high concentrations of the eluted cement. Pure PC was not cytotoxic, even at high concentration of 100mg/ml. Microscopic images showed that none of the formulations of PC caused damage cell lines. Statistical analysis of apoptosis/necrosis data showed that PC and PC plus radiopacifiers agents promoted death by necrosis statistically significant only at 100mg/ml. The results showed that PC associated with bismuth oxide, zirconium oxide or calcium tungstate were not toxic to ROS 17/2.8 or mPDL, and may be good alternatives as radiopacifier agents. The antimicrobial and pH of Portland cement and radiopacifier agents were evaluated. For antimicrobial activity agar diffusion was... (Complete abstract click electronic access below)