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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.
321

Intercambialidade de componentes protéticos em diferentes marcas de implantes / Evaluation of the connecting accuracy of interchanged prosthetic abutments to different dental implants using scanning electron microscopy

Zanardi, Piero Rocha 05 November 2012 (has links)
O presente estudo avaliou a intercambiabilidade dos componentes protéticos de implantes de hexágono externo medindo-se a precisão da interface implante/pilar (I/P) com microscopia eletrônica de varredura. Foram utilizados dez implantes para cada uma de três marcas (SIN, Conexão, Neodent) com seus respectivos pilares (base metálica de CoCr , rotacional e não rotacional) e um de marca alternativa (Microplant) em um arranjo com todas as combinações de I/P possíveis. O valor de referência para a intercambiabilidade das várias marcas de componentes foi definido pela diferença do pilar original para com seu respectivo implante. Dessa maneira, a intercambiabilidade foi considerada válida quando o resultado para um determinado pilar colocado sobre um implante fosse igual ou menor que a diferença medida, quando o pilar da mesma marca do implante foi posicionado. Um grau de desajuste foi observado em todos os espécimes. De uma maneira geral, o pilar antirrotacional foi mais preciso do que o rotacional. Estes variaram de 0,6 16,9m, com mediana 4,6m, enquanto o antirrotacional foi de 0,3 12,9m, com mediana de 3,4m. Os espécimes com o pilar e o implante Conexão tiveram uma diferença maior que o conjunto original para SIN e NEO (p<0,05). Apesar de estes últimos apresentarem resultados semelhantes com seus respectivos pilares, quando trocados, não mantiveram a mesma precisão original. Os resultados sugerem que a marca alternativa seria a única que apresentaria compatibilidade com todos os sistemas, enquanto as outras marcas não seriam completamente intercambiáveis. / The present study evaluated the interchangeability of prosthetic components for external hexagon implants by measuring the precision of the implant/abutment (I/A) interface using scanning electron microscopy. Ten implants for each of three brands (SIN, Conexão, Neodent) were tested with their respective abutments (milled CoCr collar rotational and non-rotational) and that of an alternative manufacturer (Microplant) in randomly arranged I/A combinations. The degree of interchangeability between the various brands of components was defined using the original abutment interface gap with its respective implant as the benchmark dimension. Accordingly, when the result for a given component placed on an implant was equal to or smaller then that gap measured when the component of the same brand as the implant was positioned, interchangeability was considered valid. Some degree of maladjustment was observed on all specimens. Generally, the non-rotational component was more accurate than its rotational counterpart. The latter samples ranged from 0.6 16.9m, with a median of 4.6m; the former from 0.3 12.9m, with a median of 3.4m. Specimens with the abutment and fixture from Conexão had larger microgap than the original set for Sin and Neodent (p<0.05). Even though the latter systems had similar results with their respective components, their interchanged abutments did not reproduce the original accuracy. The results suggest that the alternative brand abutment would have compatibility with all systems while the other brands were not completely interchangeable.
322

Numerical simulations of the micro flow field in the hinge region of bileaflet mechanical heart valves

Simon, Helene Anne 06 July 2009 (has links)
Native heart valves with limited functionality are commonly replaced by a bileaflet mechanical heart valve (BMHV). However, despite their widespread use, BMHVs still cause major complications, including hemolysis, platelet activation, and thromboembolic events. These complications are believed to be due to the non-physiologic hemodynamic stresses imposed on blood elements by the hinge flows. Three-dimensional characterization of the hinge flows is therefore crucial to ultimately design BMHVs with lower complication rates. This study aims at simulating the pulsatile 3D hinge flows of various BMHVs placed and estimating the thromboembolic potential associated with each hinge. The hinge and leaflet geometries of clinical BMHVs are reconstructed from micro-computed tomography scans. Simulations are conducted using a Cartesian sharp-interface immersed-boundary methodology combined with a second-order accurate fractional-step method. Physiologic flow boundary conditions and leaflet motion are extracted from the Fluid-Structure-Interaction simulations of the BMHV bulk flow. The accuracy of the solver is assessed by comparing the results with experimental data. The numerical results are analyzed using a particle tracking approach coupled with existing blood damage models to relate the flow structures to the risk for blood damage. Calculations reveal complex, unsteady, and highly 3D flow fields. Zones of flow stagnation and recirculation, favorable to thrombosis and regions of elevated shear stresses, which may induce platelet activation, are identified throughout the hinge and cardiac cycle. The hinge gap width and, more importantly, the shape of the hinge recess and leaflet are found to impact the flow distribution. Avoiding sharp corners or sudden shape transitions appear as key geometrical design parameters to minimize flow disturbances and thromboembolic potential. The computed flows underscore the need to perform full 3D pulsatile simulations throughout the cardiac cycle to fully capture the complexity and unsteadiness of the hinge flows. Though based only on three different designs, this study provides general guidelines to optimize the hinge design based on hemodynamic performance and thromboembolic potential. The developed framework enables rapid and cost-efficient pre-clinical evaluation of prototype BMHV designs prior to valve manufacturing. Application to a wide range of hinges with varying design parameters will eventually help in determining the optimal hinge design.
323

Kineziterapijos poveikis tiriamųjų emocinei būklei ir klubo sąnario funkcijai po skirtingų klubo sąnario endoprotezavimo operacijų / Physical therapy influence of the patients emotional condition and hip joint function after different hip joint endoprosthesis operations

Venslovaitis, Linas 10 September 2013 (has links)
Klubo sąnario endoprotezavimo operacija efektyviai sumažina arba visiškai panaikina skausmus, daugeliu atveju atstato funkcinį kojos stabilumą ir atraminę funkciją, iš dalies, bet ne visiškai atstato sąnario mobilumą (Drobniewski et al., 2012). Susidėvėjęs klubo sąnarys keičiamas cementiniu, becemenčiu arba mišriu endoprotezu (Laupacis et al., 2002). Darbo objektas: tiriamųjų emocinė būklė bei klubo sąnario funkcija po klubo endoprotezavimo operacijos. Darbo tikslas: įvertinti kineziterapijos poveikį cementinio ir becemenčio endoprotezų grupių ligoniams po klubo sąnario endoprotezavimo operacijos dėl koksartrozės, ankstyvajame reabilitacijos etape. Hipotezė: manome, kad kineziterapijos taikymas ankstyvajame reabilitacijos etape po klubo endoprotezavimo operacijos turėtų labiau pagerinti klubo sąnario funkciją becemenčio nei cementinio endoprotezo grupėje. Darbo uždaviniai: 1) Įvertinti cementinio endoprotezo grupės tiriamųjų operuoto klubo sąnario funkciją bei emocinę būklę prieš ir po kineziterapijos; 2) Įvertinti becemenčio endoprotezo grupės tiriamųjų operuoto klubo sąnario funkciją bei emocinę būklę prieš ir po kineziterapijos; 3) Palyginti operuoto klubo sąnario funkciją bei emocinę būklę tarp grupių prieš ir po kineziterapijos. Tyrimas atliktas AB „Ortopedijos technika“, kuriame dalyvavo 14 pacientų po klubo sąnario endoprotezavimo operacijos dėl koksartrozės. Jie buvo suskirstyti į dvi grupes: cementinio ir becemenčio endoprotezo grupes. Testavimai atlikti dukart –... [toliau žr. visą tekstą] / Endoprosthesis operation of the hip joint relieves or removes pain, restores functional leg stability and function of the supporting foot (Drobniewski et al., 2012). The obsolete hip joint is changed to cemented, cementless or hybrid hip prosthesis (Laupacis et al., 2002). Object: patients emotional condition and hip joint function after hip joint endoprosthesis operation. The purpose of the study was to evaluate influence of physical therapy between cemented and cementless hip prosthesis groups after hip joint endoprosthesis operation due to coxarthritis at early rehabilitation process. Hypothesis: applying physical therapy after hip joint endoprosthesis operation at early rehabilitation process should more improve hip joint function in cementless than in cemented hip prosthesis group. The tasks: 1) To evaluate operated hip joint function and emotional condition of the cemented hip prosthesis group before and after physical therapy. 2) To evaluate operated hip joint function and emotional condition of the cementless hip prosthesis group before and after physical therapy. 3) To compare hip joint function and emotional condition after operation between groups before and after physical therapy. The research has been done at AB „Ortopedijos technika“. All 14 patients were after hip joint endoprosthesis operations due to coxarthritis. They were divided into two groups: cemented and cementless hip prosthesis groups. Subjects were tested before and after psysical therapy use. It... [to full text]
324

Análise comparativa da interface entre intermediários e estruturas fundidas e CAD/CAM em Co-Cr e zircônia antes e após queima de cerâmica e ciclagem mecânica / Comparative analysis of the interface between different abutments and casted or CAD/CAM prostheses before and after ceramic firing and behavior after mechanical cycling.

Vitor Coró 05 July 2013 (has links)
As próteses sobre implantes apresentam alto índice de sucesso, mas ainda existem relatos de complicações técnicas e mecânicas, principalmente em relação à adaptação e desaperto de parafusos. Técnicas CAD/CAM foram desenvolvidas tentando melhorar adaptação e passividade, e hoje existem vários materiais e sistemas como opção de trabalho. A proposta deste estudo foi avaliar, por meio de leitura em microscópio, a adaptação de próteses de três elementos sobre dois implantes confeccionadas em diferentes materiais, por diferentes técnicas, antes e após a queima de cerâmica. Também foi verificado se o método/material utilizado, assim como o grau de adaptação influenciariam no comportamento das peças frente a um ensaio de fadiga mecânica. Foram formados 5 grupos de 10 amostras (n=10). Após leituras, prensagem de cerâmica e ensaio de fadiga, os dados foram submetidos aos testes ANOVA e Tuckey-Kramers. As médias de desajuste vertical pré e pós aplicação da cerâmica (&mu;m), quando ambos parafusos apertados foram para G1: Estruturas fundidas em Co-Cr com cilindros calcináveis (26,03 ± 18,4) e (36,5 ± 9) G2: Estruturas sobrefundidas em liga de Co-Cr, utilizando cilindros com base de Co-Cr (4,86 ± 5) e (10,5 ± 6); G3: Estruturas fundidas em liga de Co-Cr, associadas à técnica do cilindro cimentado (0 ± 0)e (0 ± 0); G4: Estruturas usinadas em Co-Cr CAD/CAM (0 ± 0) e (2,7 ± 2);G5: Estruturas usinadas em Zircônia CAD/CAM (14,87 ± 9) e (15,2 ± 8). Para a condição de medida com apenas um dos lados apertado, pré e pós cerâmica, do lado parafusado, os resultados foram para G1: 9,63 ± 1 e 34,8 ± 8; G2: 2,37 ± 5 e 11,9 ± 9; G3: 0 ± 0 e 0 ± 0; G4: 0 ± 0 e 3,4 ± 3; G5: 17,69 ± 1 e 20,8 ± 9. Para a condição de medida com apenas um dos lados apertado, pré e pós cerâmica, do lado desparafusado, os resultados foram para G1: 124,22 ± 37 e 129,8 ± 37; G2: 64,79 ± 47 e 80,6 ± 46; G3: 12,34 ± 17 e 2,1 ± 3; G4: 3,54 ± 5 e 17,6 ± 8; G5: 37,77 ± 25 e 42,4 ± 19. O torque de desaperto (Ncm) dos parafusos protéticos foi verificado antes e após ensaio de fadiga com 300.000 ciclos. Os valores médios encontrados foram respectivamente: G1: 5,80 ± 1,23 e 4,11 ± 1,16; G2: 6,30 ± 1,00 e 3,32 ± 0,87; G3: 5,63 ± 1,05 e 3,30 ± 1,46; G4: 7,24 ± 1,05 e 3,44 ± 1,62; G5: 7,75 ± 1,25 e 6,78 ± 1,18. Os grupos CC, Co-Cr CAD/CAM e Zi, apresentaram os melhores resultados quanto ao ajuste vertical, seguidos pelo grupo Co-Cr e calcinável. Os grupos CC, Co-Cr e Co-Cr CAD/CAM apresentaram perda de torque dos parafusos protéticos após oensaio de fadiga mecânica. O grupo Zi teve menor perda de torque entretodos grupos, comparando antes e após o teste de fadiga. Nenhum dos grupos apresentou perda de torque suficiente para que a prótese perdesse estabilidade da junção. / The implant-supported prostheses present a high success rate, but there are still reports of technical and mechanical complications, mainly regarding adaptation and loosening of screws. CAD/CAM techniques have been developed trying to improve adaptation and passivity, and today there are many options of materials and systems to work with. The purpose of this study was to evaluate, by microscope, fitting of three elements prostheses retained by two implants, made of different materials, different techniques, before and after ceramic firing. It was also verified if the method/material used, as well as the degree of adjustment would influence on the behavior of the prostheses after a fatigue test. Five groups of ten specimens were formed (n = 10). After reading, ceramic pressing and fatigue test data were submitted to ANOVA and Tukey-Kramer\'s tests. The mean vertical misfit pre and post application of ceramic (&mu;m), whit both screws tightened to G1: Structures casted in Co-Cr with castable cylinders (26.03 ± 18.4) and (36.5 ± 9) G2: Structures casted in Co-Cr, with Co-Cr basis cylinder (4.86 ± 5) (10.5 ± 6); G3: Structures casted in Co-Cr associated with the cemented cylinder technique (0 ± 0) and (0 ± 0); G4: Machined structures in Co-Cr CAD/CAM (0 ± 0) and (2.7 ± 2), G5: Structures machined in zirconia CAD/CAM (14.87 ± 9) and (15.2 ± 8). To the measurement condition of only one side tighted, pre and post ceramic, on the tightned side, the results were G1: 9.63 ± 1 and 34.8 ± 8; G2: 2.37 ± 5 and 11.9 ± 9; G3: 0 ± 0 and 0 ± 0; G4: 0 ± 0 and 3.4 ± 3; G5: 17.69 ± 1 and 20.8 ± 9. To the measurement condition of only one side tightened, pre and post ceramic, on the untightened side, the results were in G1: 124.22 ± 37 and 129.8 ± 37; G2: 64.79 ± 47 and 80.6 ± 46; G3: 12.34 ± 2.1 and 17 ± 3; G4: 5 ± 3.54 and 17.6 ± 8; G5: 37.77 ± 25 and 42.4 ± 19. The loosening torque of the prosthetic screws (Ncm) was checked before and after fatigue test to 300,000 cycles. The mean values were: G1: 5,80 ± 1,23 e 4,11 ± 1,16; G2: 6,30 ± 1,00 e 3,32 ± 0,87; G3: 5,63 ± 1,05 e 3,30 ± 1,46; G4: 7,24 ± 1,05 e 3,44 ± 1,62; G5: 7,75 ± 1,25 e 6,78 ± 1,18. CC groups, Co-Cr CAD/CAM and Zi, showed the best results regarding vertical adjustment, followed by the Co-Cr group and castable. CC groups, Co-Cr and Co-Cr CAD/CAM presented loss of torque after fatigue test. The Zi group showed less loss of torque among all groups, comparing before and after fatigue test. None of the groups showed enough loosening to loose joint stability.
325

Influência de pigmentos e opacificadores na estabilidade de cor, dureza, absorção e solubilidade de um silicone facial submetido ao envelhecimento acelerado

Santos, Daniela Micheline dos [UNESP] 27 May 2009 (has links) (PDF)
Made available in DSpace on 2014-06-11T19:35:03Z (GMT). No. of bitstreams: 0 Previous issue date: 2009-05-27Bitstream added on 2014-06-13T19:44:51Z : No. of bitstreams: 1 santos_dm_dr_araca.pdf: 1533021 bytes, checksum: 248d1fb3f8ac9369529ebf0ea03f0654 (MD5) / Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP) / O presente estudo teve por objetivo avaliar a influência de dois pigmentos (pó de cerâmica e tinta a óleo) e um opacificador (sulfato de barium) sobre as propriedades físicas de estabilidade de cor, dureza, absorção e solubilidade do silicone facial MDX4-4210, submetido ao envelhecimento acelerado. Para a confecção das amostras, foram utilizadas 2 matrizes metálicas em alumínio, contendo em seu interior 10 compartimentos circulares com 45mm de diâmetro apresentando estes, em uma matriz, uma espessura de 2mm para os testes de estabilidade de cor e dureza e, na outra, 1mm para os ensaios de absorção e solubilidade. Foram confeccionadas 120 amostras, metade para os ensaios de análise cromática e dureza e, a outra metade, para o teste de absorção e solubilidade. As amostras destinadas para cada teste foram distribuídas em seis grupos, incolor (G1), incolor com opacificador (G2), cerâmica (G3), cerâmica com opacificador (G4), óleo (G5), óleo com opacificador (G6). Após a obtenção das amostras, a análise cromática inicial foi verificada por meio da análise visual e da espectrofotometria de reflexão. Os ensaios de dureza foram realizados com auxílio de um durômetro Shore A. Os testes de absorção e solubilidade foram realizados por meio de um dessecador no qual as amostras permaneceram neste ambiente em estufa à temperatura de 37±2°C, sendo pesadas diariamente até obtenção de massa constante (W1); posteriormente as amostras foram submetidas ao envelhecimento seguido de nova pesagem (W2), e nova dessecação com pesagem final (W3). As amostras foram submetidas ao envelhecimento acelerado por 1008 horas, sendo os ensaios realizados nos períodos correspondentes a 252, 504 e 1008 horas. Os dados obtidos foram submetidos à ANOVA e Tukey, com significância de 5%. Pode-se observar pela análise espectrofotométrica que os grupos com opacificador apresentaram melhor... / The aim of this study was to evaluate the influence of two pigments (ceramic powder and oil paint) and one opacifier (barium sulfate) on physical properties of color stability, hardness, absorption and solubility of the facial silicone MDX4-4210 submitted to artificial aging. The replicas were fabricated in two metallic matrixes in aluminum containing 10 circular compartments with 45mm in diameter. One matrix generated specimens with 2mm in thickness for color stability and hardness evaluations while the other matrix, specimens with 1mm in thickness for absorption and solubility tests. The replicas were divided into six groups: colorless (G1), colorless with opacifier (G2), ceramic (G3), ceramic with opacifier (G4), oil (G5) and oil with opacifier (G6). Initial chromatic evaluation was performed by visual analysis and reflection spectrophotometry. The hardness tests were carried out by a Shore A durometer. The evaluations of absorption and solubility were performed through a desiccator to maintain the replicas in a stove at 37±2°C. The specimens were weighed daily until obtaining a constant mass, (W1). Then, the replicas were submitted to aging followed by a new weighing (W2) and drying with final weighing (W3). The replicas were submitted to accelerated aging during 1008 hours with evaluation after 252, 504 and 1008 hours. Data were submitted to statistical analysis by ANOVA and Tukey’s test at 5% level of significance. According to spectrophotometry, the groups with opacifier presented statistically significant better chromatic stability than the other groups. The accelerated aging generated significant chromatic alterations in all groups, except for colorless and oil groups both with opacifier. There was no statistically significant difference among the groups after aging regarding hardness, absorption and solubility. According to the results, it may be concluded that... (Complete abstract, click electronic access below)
326

"Estudo experimental da transmissão da pulsatilidade da endoprótese à parede do aneurisma da aorta após correção endoluminal" / Pulsatility transmission from endograft to aortic aneurysm wall after endovascular repair : an experimental study

Hussein Amin Orra 26 September 2005 (has links)
Objetivo: Medir a pulsatilidade da parede do aneurisma de aorta humano antes e depois de sua correção endoluminal. Método: Cinco aneurismas foram submetidos à perfusão pulsátil antes e depois do implante de uma endoprótese. Resultado: o nível da coluna de água oscilou durante a pulsação com variações de 17, 16, 13, 7 e 25 cm antes da colocação da endoprótese. Depois da prótese, a oscilação diminuiu em todos os casos para 13, 12, 9, 3,5 e 23 cm, respectivamente. Conclusão: A pulsação da endoprótese é transmitida à parede do aneurisma / Objective: To measure the pulsatility of human aortic aneurysms before and after exclusion with endograft. Method: Five aneurysms were submitted to pulsatile perfusion before and after implantation of a bifurcated endograft. Result: The level of the water column oscillated during pulsation, in each case, with an amplitude of 17, 16, 13, 7 and 25 cm before the endograft insertion. After that, the amplitudes dropped to, respectively 13, 12, 9, 3.5 and 23 cm.Conclusion: Pulsation of an endograft is transmitted to the aneurysm wall even in the absence of endoleak
327

Analise fotoelastica da distribuição de tensões em dois sistemas de proteses mandibulares sobre implantes : barra distal e solda a laser / Photoelastic analysis of the distribution of the tensions in two systems of mandibular prosthesis over implants : distal bar and laser welding

Salles, Angelo Emilio Barroso de 12 August 2018 (has links)
Orientador: Mauro Antonio de Arruda Nobilo / Dissertação (mestrado) - Universidade Estadual de Campinas, Faculdade de Odontologia de Piracicaba / Made available in DSpace on 2018-08-12T16:14:35Z (GMT). No. of bitstreams: 1 Salles_AngeloEmilioBarrosode_M.pdf: 10746117 bytes, checksum: 7a6d08147fb33c8d235cc7df5f8be032 (MD5) Previous issue date: 2008 / Resumo: Este estudo avaliou por meio de análise fotoelástica, a distribuição in vitro das tensões geradas na interface "osso/implante" em próteses mandibulares, tipo protocolo, comparando duas técnicas de confecção: Solda a laser e Barra Distal (Neodent, Curitiba - PR) onde não se utiliza infra-estrutura metálica. Foram confeccionadas duas próteses com design similares (uma para cada técnica), sobre uma matriz metálica simulando um arco mandibular edêntulo, onde foram instaladas cinco réplicas de implantes de corpo único (GT- Neodent, Curitiba - PR). A partir de um molde de silicone de duplicação (Silibor - Clássico Artigos Odontológicos Ltda.) foi confeccionado um modelo em resina fotoelástica (Araldite GY279BR - Araltec Produtos Químicos Ltda. Guarulhos - SP) com cinco implantes GT (Neodent, Curitiba - PR) incorporados. Após a instalação de cada prótese sobre o modelo fotoelástico, utilizando 10 N/cm para aperto dos parafusos, foi realizada análise fotoelástica. Em seguida, foi aplicada carga oclusal de 100 N em toda extensão de cada prótese, com auxílio de uma placa metálica posicionada sobre a face oclusal dos dentes, e então realizada nova análise das tensões. Estas análises foram executadas com o auxílio de um polariscópio circular acoplado a uma máquina fotográfica digital (H1 - Sony, Japão), que permitiu a visualização das franjas e registrou através de fotografias digitais o comportamento das mesmas ao redor dos implantes no modelo fotoelástico. De acordo com os resultados, concluiu-se que a técnica utilizando Barra Distal distribuiu melhor, e transmitiu com menos intensidade, após o aperto dos parafusos, as tensões geradas na interface "osso/implantes" do que a técnica utilizando solda a laser. No entanto, ocorreu o inverso após o carregamento oclusal. / Abstract: The aim of this study was to evaluate through photoelastic analysis, the in vitro distribution of the generated tensions in the "bone/ implant" interface in mandibular prostheses, protocol type, comparing two different working techniques: the idealized by Branemark and Distal Bar (Neodent, Curitiba - PR) where framework is not used. Two similar prostheses were made (one for each technique), on a metal matrix simulating an edentulous mandible, where five replications of single body implant were installed (GT-Neodent, Curitiba - PR). From a silicone mold for duplication (Silibor - Classico Artigos Odontológicos Ltda.), a model in photoelastic resin was created (Araldite GY279BR - Araltec Produtos Quimicos Ltda., Guarulhos - SP) with five GT implants (Neodent, Curitiba - PR) embedded. After the installation of each prosthesis on the photoelastic model, using 10 N/cm for tightening the screws, a photoelastic analysis was performed. Then a 100 N occlusion load was applied throughout each prosthesis extension with the help of a metal plate positioned on the occlusal face of the teeth, and then a new analysis of the tensions was conducted. These analyses were performed with the help of a circular polariscope attached to a digital camera (H1 - Sony, Japan), which allowed the visualization of the fringes and recorded by digital photos the behaviour of the implants. According to the results, it was concluded that the Distal Bar technique distributed better, and transmitted with less intensity, after the tightening of the screws, the generated tensions to the system "bone/implants" than the laser welding. However, it happened the opposite after the occlusal load. / Mestrado / Protese Dental / Mestre em Clínica Odontológica
328

Intercambialidade de componentes protéticos em diferentes marcas de implantes / Evaluation of the connecting accuracy of interchanged prosthetic abutments to different dental implants using scanning electron microscopy

Piero Rocha Zanardi 05 November 2012 (has links)
O presente estudo avaliou a intercambiabilidade dos componentes protéticos de implantes de hexágono externo medindo-se a precisão da interface implante/pilar (I/P) com microscopia eletrônica de varredura. Foram utilizados dez implantes para cada uma de três marcas (SIN, Conexão, Neodent) com seus respectivos pilares (base metálica de CoCr , rotacional e não rotacional) e um de marca alternativa (Microplant) em um arranjo com todas as combinações de I/P possíveis. O valor de referência para a intercambiabilidade das várias marcas de componentes foi definido pela diferença do pilar original para com seu respectivo implante. Dessa maneira, a intercambiabilidade foi considerada válida quando o resultado para um determinado pilar colocado sobre um implante fosse igual ou menor que a diferença medida, quando o pilar da mesma marca do implante foi posicionado. Um grau de desajuste foi observado em todos os espécimes. De uma maneira geral, o pilar antirrotacional foi mais preciso do que o rotacional. Estes variaram de 0,6 16,9m, com mediana 4,6m, enquanto o antirrotacional foi de 0,3 12,9m, com mediana de 3,4m. Os espécimes com o pilar e o implante Conexão tiveram uma diferença maior que o conjunto original para SIN e NEO (p<0,05). Apesar de estes últimos apresentarem resultados semelhantes com seus respectivos pilares, quando trocados, não mantiveram a mesma precisão original. Os resultados sugerem que a marca alternativa seria a única que apresentaria compatibilidade com todos os sistemas, enquanto as outras marcas não seriam completamente intercambiáveis. / The present study evaluated the interchangeability of prosthetic components for external hexagon implants by measuring the precision of the implant/abutment (I/A) interface using scanning electron microscopy. Ten implants for each of three brands (SIN, Conexão, Neodent) were tested with their respective abutments (milled CoCr collar rotational and non-rotational) and that of an alternative manufacturer (Microplant) in randomly arranged I/A combinations. The degree of interchangeability between the various brands of components was defined using the original abutment interface gap with its respective implant as the benchmark dimension. Accordingly, when the result for a given component placed on an implant was equal to or smaller then that gap measured when the component of the same brand as the implant was positioned, interchangeability was considered valid. Some degree of maladjustment was observed on all specimens. Generally, the non-rotational component was more accurate than its rotational counterpart. The latter samples ranged from 0.6 16.9m, with a median of 4.6m; the former from 0.3 12.9m, with a median of 3.4m. Specimens with the abutment and fixture from Conexão had larger microgap than the original set for Sin and Neodent (p<0.05). Even though the latter systems had similar results with their respective components, their interchanged abutments did not reproduce the original accuracy. The results suggest that the alternative brand abutment would have compatibility with all systems while the other brands were not completely interchangeable.
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Diagnosis of orthopaedic prosthesis infections with radionuclide techniques; clinical application of various imaging methods

Larikka, M. (Martti) 23 January 2004 (has links)
Abstract A variety of radiopharmaceuticals and imaging techniques are currently available for scintigraphic imaging of infections. However, comparisons on the clinical value of such techniques have been limited, especially in prosthesis infections. This series included 138 cases with suspected prosthesis infections – 94 in hip and 44 in knee prostheses of patients whose final diagnoses were based on clinical, operative and microbiological findings, and who underwent three-phase bone, 99mTc -leukocyte and 99mTc-ciprofloxacin imaging in the Department of Clinical Chemistry, Oulu University Hospital and in the Laboratory, L?nsi-Pohja Central Hospital, during the years from 1993 to 2001. The normal arterial and soft-tissue phase images of three-phase bone imaging practically excluded infection in hip prostheses, whereas these techniques frequently yielded false positive findings in patients with knee prostheses, resulting in specificity of 23% or less. In combined 99mTc-leukocyte/bone imaging, diagnostic accuracy was 80–86% at two- to four-hour images and 87–98% at 24-hour images. The 99mTc-ciprofloxacin images showed unspecific accumulation of tracer in the one-hour and four-hour images, which disappeared in the 24-hour images in most hip and knee prostheses. 99mTc-ciprofloxacin imaging yielded almost as good diagnostic accuracy as combined 99mTc-leukocyte/bone imaging. In conclusion, in suspected hip prosthesis infections, normal findings in three-phase bone imaging exclude infection, whereas abnormal results in the arterial and soft-tissue phases should be confirmed with 99mTc-leukocyte imaging using 24-hour images. Contrary-wise, in suspected knee prosthesis infections, 99mTc-leukocyte imaging with 24-hour images is the first-line examination, and abnormal results in 24-hour images should be confirmed by using 99mTc-bone-metabolic imaging. 99mTc-ciprofloxacin yielded almost equally good results as 99mTc-leukocyte/bone-metabolic imaging, but unfortunately, the tracer is not commercially available, although it has been patented.
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Machine d'essai de prothèse pour Transtibial et Transfemoral / Testing Machine for Transtibial and Transfemoral Prosthesis

Fouda, Khaled 21 December 2017 (has links)
L'objectif de ce travail est de construire une machine d'essai pour la prothèse. La machine doit être capable de reproduire les mêmes conditions dynamiques et cinématiques appliquées sur la prothèse pendant l'utilisation normale.Le nombre d'amputation et les causes d'amputation ont été recueillis. Différents types de prothèses ont été classés selon la prothèse de jambe par hauteur d'amputation, prothèse passive et active, différenciées par la nature de leur actionneur. La plupart des machines d'essai pour la prothèse ont été étudiées à partir de la prospective technologique et capacitaire. Déterminer toutes les limitations de la plupart des machines d'essai existantes, et les besoins de développer une nouvelle machine pour remplir complètement ces besoins ont été développés.Ensuite, nous avons étudié et analysé la dynamique de la marche et de la course humaines. Les équations du mouvement en prenant en considération les masses et les moments d'inertie des segments squelettiques. La plupart des paramètres de la démarche ont été extraits. En conclusion, nous avons les exigences cinématiques du centre de gravité humain pour générer 6 DOF que la machine d'essai devrait effectuer pour imiter la démarche humaine normale et courir.Trois conceptions ont été proposées pour implanter la machine d'essai; Bras de robot articulé, manipulateur cartésien et Stewart Platform (SP). Après la mise en œuvre des trois solutions, nous avons trouvé la solution la plus appropriée est le SP attaché avec une hanche active artificielle. Nous avons choisi la puissance hydraulique car c'est la technique d'actionnement la plus appropriée pour notre solution, connaissant les forces d'actionnement requises.Pour aider à contrôler le mouvement de SP, une nouvelle solution de modèle géométrique direct pour la planeuse et la plate-forme Stewart 6-6 a été développée en utilisant les capteurs rotatifs au lieu de capteurs de revêtement comme voulu pour les actionneurs hydrauliques. L'analyse de sensibilité a été étudiée pour cette solution, et un calcul analytique pour le calcul de l'espace de travail a également été développé.La conclusion de cette machine d'essai est que nous pouvons créer toute la dynamique du corps humain, c'est-à-dire marcher ou courir ou monter et descendre des escaliers. La solution développée peut porter des procédures d'essai pour la prothèse passive ou active. / The objective of this work is to build a testing machine for prosthesis. The machine should be able to reproduce the same dynamic and kinematics conditions applied on the prosthesis during the normal use.Numbers of amputation, and causes of amputation were collected. Different types of prosthesis were classified according to the leg prosthesis per amputation height, passive and active prosthesis, differentiated by the nature of their actuator. Most of the testing machine for the prosthesis were studied form the technological and capability prospective. Determining all the limitations of most of existing testing machines, and the needs to develop a new machine to full fill these needs were developed.Then we studied and analyzed the dynamics of the human gait and run. The equations of motion by taking into consideration the masses and moments of inertia of skeletal segments. Most of the parameters of gait were extracted. In conclusion, we have the kinematic requirements of the human center of gravity to generate 6 DOF that the testing machine should carry out to emulate the normal human gait and run.Three designs were proposed to implement the testing machine; Articulated robot arm, Cartesian manipulator, and Stewart Platform (SP). After implementing the three solutions we found the most suitable solution is the SP attached with it an artificial active hip. We have chosen the hydraulic power as it is the most suitable actuation technique for our solution knowing the required actuation forces.To help in controlling the SP motion, a novel Closed-form solution of direct Geometric model for planer and 6-6 Stewart Platform using the rotary sensors instead of liner sensors as wanted to the hydraulic actuators was developed. Sensitivity analysis was studied for that solution, and analytical calculation for computing the workspace was also developed.The conclusion from this testing machine is that we can create all the dynamics of the human body, i.e. walking or running or going up and down stairs. The developed solution can carry testing procedures for either passive or active prothesis.

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