Les travaux menés au cours de cette thèse portent sur la microfabrication d'interfaces neuro-électroniques pour des applications en neurosciences. Nous avons choisi de nos focaliser sur la réhabilitation fonctionnelle motrice et sensorielle en développant différentes matrices de micro-électrodes (MEA) respectivement, des sondes neuronales rigides et des implants rétiniens souples. Selon les applications visées, deux types de substrats ont été utilisés pour concevoir ces MEA. Pour des analyses ou expériences in-vitro, les MEA (sondes neuronales) ont plutôt été réalisées sur des substrats rigides tels que le silicium ou le verre, tandis que pour les expériences in-vivo, les MEA (implants rétiniens) ont été réalisées sur des substrats souples tels que des polymères biocompatibles (polyimide ou parylène). Ces MEA ont été fabriquées avec différents matériaux d'électrodes (diamant dopé, platine, platine noir et or) qui ont également été testés afin de déterminer leur capacité en enregistrement et/ou stimulation. De plus, à l'aide de travaux de modélisation numérique, nous avons validé le concept d'une géométrie tridimensionnelle avec grille de masse permettant une stimulation plus focale des cellules. Cette thèse a ainsi contribué à stabiliser différents procédés de fabrication pour obtenir des MEA plus reproductibles ainsi que pour améliorer leur rendement. Elle a également permis d'établir un suivi et un protocole expérimental pour assurer une traçabilité des MEA et contrôler leur performances à toutes les étapes : depuis leur fabrication au moyen de techniques électrochimiques (CV, EIS) jusqu'aux expériences biologiques in-vitro et in-vivo / The work lead during this thesis deals with microfabrication of neuro-electronic interfaces for neuroscience applications. We have chosen to focus on motor and sensory function rehabilitations by developing Micro-Electrode Arrays (MEA) respectively, rigid neural probes and flexible retinal implants. According to the targeted applications, two types of substrates have been used to achieve these MEA. For analysis or in vitro experiments, neural probes MEA have been realized on rigid substrates such as silicon or glass whereas for in-vivo experiments, retinal implants MEA have been realized on flexible substrates such as biocompatible polymers (polyimide or parylene). These MEA were made with different electrode materials (boron doped diamond, platinum, black platinum and gold) which have been tested to determine their capability in recording and/or stimulation. Moreover, with numerical modelling work, we have validated a tridimensional geometry concept with a ground grid which permits a more local stimulation of cells. This thesis has contributed to stabilize different fabrication processes to obtain more repeatable MEA and also to improve their yield. It also allowed the set-up of a follow-up and an experimental protocol to insure MEA traceability and to monitor their performances at each step since their fabrication through means of electrochemical techniques (CV, EIS) to in vitro and in-vivo biological experiments

The objective of this study was to compare effect of surface treatment and fatigue to the retention of zirconia crowns luted to two different heights of titanium abutments. Thirty titanium base 3.5 mm (n = 15) and 5.5 mm in height (n = 15) and thirty zirconia crowns were used. Group A (n = 10), 3.5-mm-height titanium base with no surface treatment; Group B (n = 5), 3.5-mm-height titanium base with surface treatment; Group C (n = 5), 3.5-mm-height titanium base with no surface treatment with fatigue test; Group D (n = 5), 3.5-mm-height titanium base with surface treatment and fatigue test. The identical group allocation was utilized to 5.5-mm-height titanium base groups, Group E, F, G and H respectively. All zirconia crowns and titanium abutments of the groups with surface treatment were particle abraded with 50 μm alumina. All specimens were subjected to a pull-out test. Data were analyzed with ANOVA and the Tukey HSD test. Pull-out retention forces for each group were: Group A: 288 ± 97.5 N, Group B: 198.71 ± 82.94 N, Group C: 537.61 ± 80.13 N, Group D: 600.11 ± 27.23 N, Group E: 240.68 ± 54.33 N, Group F: 270.92 ± 16.43 N, Group G: 707.03 ± 32.30 N, and Group H: 831.19 ± 55.50 N. Particle abrasion of the titanium base significantly increased zirconia crown retention. The height of the titanium base had a significant influence on retention force in particle-abraded groups. The fatigue test did not decrease retention force. / 2018-09-26T00:00:00Z

A research report submitted to the School of Oral Health Sciences, Faculty of Health Sciences, University of the Witwatersrand, in partial fulfillment of the requirements for the degree of Master of Dentistry in the branch of Prosthodontics Johannesburg, 2017 / Purpose: To perform a comparative analysis of the accuracy of intra-oral and extra-oral digital scanners when used for the milling of a long-span implant supported superstructure framework. Method: Three intra-oral and three extra-oral scanners were used to measure a master model containing five implant analogues. The three-dimension positions of the implant analogues were measured with a coordinate measuring machine. The digital data from the scanners were used to mill the implant positions in aluminium blanks from a single milling device. These implant positions were measured at the same points as the master model. The three-dimensional differences were calculated to provide a measure of the most accurate frameworks. Results: For the intra-oral scanners, the further the measurement between points, the greater the standard deviation (the poorer the precision) and the poorer the mean accuracy. However, these were clinically acceptable over short distances. For the extra-oral scanners, there was no correlation between the length of the measured distances and the accuracy of the produced framework. All the extra-oral scanners were clinically acceptable for complete-arch prostheses. Conclusions: Noting the limitations of this study and the use of a milling centre to mill the frameworks, for the intra-oral scanners, the 3Shape Trios® (3Shape, Copenhagen, Denmark) can be used for measurements up to 21,5mm and the Sirona CEREC OmniCam (Sirona Dental Systems, Inc., Bensheim, Germany) can be used for measurements up to 34mm. The extra-oral scanners used in this study can be used for complete-arch implant prosthetics. The accuracy of these is relative to the model or impression created. Steps should therefore be made to ensure the accuracy of the model such as the use of a verification jig / MT2017

Ph.D., Faculty of Health Sciences, University of the Witwatersrand, 2008. / Lumbar disc replacement is a rapidly expanding surgical treatment modality for longstanding back and leg pain due to intervertebral disc degeneration. Compared to fusion surgery, it has the advantage of preserving segmental mobility, but convincing evidence of superiority over fusion surgery is missing. As part of this research project, I participated in the development of a new intervertebral disc prosthesis, with several international patents attached to the design of the prosthesis, the instrumentation and the insertion technique. The Kineflex (Centurion) lumbar disc is a mechanical, un-constrained, re-centering disc prosthesis developed in South Africa. After the development and manufacturing of the disc, prototype test racks were custom-made at the premises of the manufacturer and the disc was extensively tested for mechanical wear and fatigue. The first implantation took place in October 2002. I prospectively captured all cases performed by our centre, with documentation including demographic data, co-morbidities, clinical history, symptoms and signs. The completed consent forms were filed. The outcome was monitored, pre-operatively and in follow-up, with complete radiological documentation of all radiographs on JPEG files. Clinical outcome results were documented using two different internationally validated questionnaires as well as our own questionnaire, which expands further on work and demographic details, previous operative and conservative treatment, and satisfaction with the treatment outcome. The aim of the this project was to develop a disc prosthesis that is suitable and safe for human implantation into the lumbar spine disc space, even in severely advanced disc degeneration and to verify this in the outcome studies presented in this thesis. Existing indications and contra-indications for artificial disc replacement were critically evaluated regarding their validity for this particular implant. Results: Chapter 3 elaborates on the extensive pre-clinical mechanical wear and fatigue testing protocol to which the Centurion (Kineflex) lumbar disc prosthesis was subjected. The results of this testing protocol, together with our early clinical outcome results, formed the basis for the awarding of the European quality recognition (CE-Mark). In these extensive in vitro studies, we were able to show the durability of the Kineflex disc prosthesis in the long term. This, together with our initial clinical outcome results, formed the basis for the acceptance into a “prospective, randomized, multicenter Food and Drug Administration investigational device exemption study of lumbar total disc replacement with the KINEFLEX Lumbar Artificial Disc versus the CHARITÉ™ Artificial Disc”. Chapter 4 is compiled from an invited submission to a new book on motion preservation surgery in the human spine, edited by leading spine surgeons in the field (James J. Yue, Rudolf Bertagnoli, Paul McAfee, and Howard An) and published by Elsevier Publishers: Chapter 42: Kineflex. In this chapter, an overview is given of the ideas behind the Kineflex disc development, as well as of the insertion instrumentation used for disc implantation. It further reports on early clinical outcome results of the first patients implanted with the device in our centre (the first 40 implantations worldwide were all performed by me). Chapter 5, our first peer reviewed international publication, reports on clinical and radiological 2-year outcome results of our first 100 patients. With the Kineflex implant, we could demonstrate equally good radiological placement accuracy in patients with severe and less severe disc degeneration of the index level, rendering the implant suitable even in severe degeneration of a spinal motion segment. Chapter 6 and Chapter 7 of this thesis consist of two further peer-reviewed publications. They both report on so-called “off-label” patient sub-groups in our disc replacement series. In Chapter 6 we present the second published series on a larger group of patients presenting with adjacent segment disease after previous lumbar fusion surgery as well as the first publication, which investigated the radiological changes in alignment parameters secondary to the disc replacement surgery in this patient group. Chapter 7 consists of the first published series on patients with “degenerative spondylolisthesis” treated with disc replacement surgery. A detailed description of the operative reduction technique is provided, which is unique to the Kineflex disc and its insertion instrumentation. In this pilot study, two-year results on a limited patient group are presented. This thesis concludes with the overall discussion in Chapter 8. It outlines the current knowledge on artificial disc replacement and places my results into perspective with recent discoveries published in the literature. It finishes with my assessment of what future research should concentrate on.

Introdução: O sucesso da prótese de palato para correção da insuficiência velofaríngea (IVF) em crianças com fissura palatina depende de muitos fatores que ainda precisam ser investigados. A pouca literatura existente nesta área é baseada, em sua grande maioria, no relato de casos clínicos, sem a investigação de todo o processo envolvido na confecção desse tipo de prótese e de possíveis intercorrências de tratamento. Objetivos: Os objetivos deste estudo foram: 1) caracterizar todas as etapas e o tempo necessário para confecção da prótese de palato em crianças com IVF decorrente de fissura labiopalatina, e 2) identificar a ocorrência de fatores que podem interferir no processo de confecção, adaptação e manutenção da prótese de palato na população estudada. Material e Método: Este estudo retrospectivo envolveu uma análise de prontuários de crianças com fissura labiopalatina unilateral, que foram encaminhadas para uso temporário da prótese de palato para correção da IVF. O grupo estudado incluiu 45 crianças (24 meninas e 21 meninos), cujas idades variaram entre 3 anos e 10 meses e 10 anos e 2 meses (Média = 6 anos e 2 meses) na época em que o tratamento com a prótese de palato foi iniciado. Um protocolo para o levantamento dos dados abordando cada fase da confecção das três partes da prótese de palato (anterior, intermediária e bulbo faríngeo) foi elaborado tratando também do tempo necessário para confecção de cada porção assim como dos dados referentes às intercorrências durante este processo. Resultados: Em geral, o tempo de confecção de todas as etapas das próteses foi, em média, de 8 meses, necessitando, para tanto, uma média de 14 atendimentos. O período entre a conclusão da prótese e o primeiro retorno para a sua manutenção foi de 8 meses, em média, sendo observada a necessidade de substituição das próteses para 56% das crianças. Conclusão: O processo de confecção de uma prótese de palato em crianças pode apresentar grande variação quanto ao número de atendimentos e ao tempo necessário para a conclusão da próteses, principalmente devido a pouca condição de suporte das próteses, à dificuldade de adaptação da criança ao uso de cada parte da prótese e à necessidade de troca da prótese antes da sua conclusão final devido ao crescimento da maxila. / Introduction: The successful use of a palatal prosthesis for correction of velopharyngeal insufficiency (VPI) in children with cleft palate depends on factors that need to be investigated. The existing literature in this area is limited and based mostly in case report, not addressing the process involved in the construction of this type of device neither describing the difficulties nor complications during this process. Objectives: The objectives of this study were: 1) to characterize all stages involved in the construction of a palatal prosthesis and the duration of this process in children with VPI associated to cleft lip and palate, and 2) to identify the occurrence of factors that can interfere in the process of construction, fitting and monitoring of the palatal prosthesis in the studied population. Material and Method: This retrospective study involved an analysis of treatment records of children with cleft lip and palate referred to temporary correction of VPI with palatal prosthesis. The group studied included 45 children (24 girls, 21 boys), with age varying between 3y10m and 10y2m (mean of 6y2m) at the time the prosthetic treatment of VPI was initiated. A data collection protocol was elaborated addressing each phase involved in the construction of all 3 parts of the palatal prosthesis (anterior, intermediary, and speech bulb), documenting the time needed to accomplish each part and recording the complications observed throughout the prosthetic treatment. Results: In general the mean duration of the process for construction of all parts of the prosthesis was 8 months with an average of 14 visits needed to finish the device. The period between the conclusion of the device and the first monitoring visit also was 8 months (average). It was observed the need for substitution of the prosthesis for 56% of the children. Conclusion: The process for the construction of a palatal prosthesis for children with VPI may present large variation in the number of visits and the duration of the process needed for the conclusion of the prosthesis, particularly due to the lack of adequate dental support for the device retention, the difficulty of the adaptation of the child to use each part of the prosthesis, and the need to substitute the prosthesis due to growth of the maxilla.

Nas próteses sobre implante, a escolha do sistema de retenção (cimentada ou parafusada) muitas vezes está relacionada com a preferência pessoal de cada profissional. Porém alguns aspectos que diferem esses tipos de prótese devem ser levados em consideração no momento desta seleção. A passividade de assentamento, a reversibilidade, a estética, a oclusão e a presença do orifício de acesso ao parafuso. A ausência de orifícios de acesso ao parafuso é uma grande vantagem quando se utilizam próteses cimentadas principalmente quando se trata de casos onde a estética é uma prioridade. Além disto, a descontinuidade da cerâmica nas próteses parafusadas pode se apresentar como um fator de fragilização para a cerâmica. Isto se torna ainda mais grave quando o orifício de acesso ao parafuso constituído apenas por cerâmica com o objetivo de minimizar sua deficiência estética. É neste sentido que o presente trabalho se propõe a avaliar a resistência à fratura da cerâmica em próteses metalo-cerâmicas implantosuportadas cimentadas e parafusadas com dois diferentes desenhos de infraestruturas. Além disto, observar se a simulação de envelhecimento da cerâmica através da ciclagem mecânica influencia na sua resistência à fratura sob carga compressiva. Para isto, 10 coroas metalo-cerâmicas cimento-retidas (Grupo controle), 10 coroas metalo-cerâmicas parafusadas diretamente sobre o implante e orifício de acesso ao parafuso em metal medindo 2mm de altura (Próteses parafusadas com \"chaminé\") e 10 coroas metalo-cerâmicas parafusadas diretamente sobre o implante com orifício de acesso ao parafuso em porcelana medindo 2mm de altura (Próteses parafusadas sem \"chaminé\") foram confeccionadas de forma padronizadas. Metade dos corpos-de-prova de cada grupo (n=5) foram submetidas ao teste de ciclagem mecânica com auxílio de uma máquina eletro-mecânica de fadiga que continha um dispositivo de aço inoxidável com a ponta da forma esférica (6mm de diâmetro) que promovia uma carga simultânea em 4 vertentes triturantes (2 vestibulares e 2 linguais), simulando um contato com o dente antagonista por 1.200.000 ciclos, com uma freqüência de contato de 2Hz e carregamento de 100N, em água a uma temperatura de 37ºC. Todos os corpos-de-prova foram submetidos ao teste de compressão axial realizado em uma máquina de testes a uma velocidade de 0,5mm/min para que um dispositivo de extremidade arredondada(6mm de diâmetro) entrasse em contato com a coroa. Os valores médios da força requerida para a fratura dos corpos-de-prova foram calculados e comparados pela análise de variância a 2 critérios (1= tipo de infra-estrutura; 2= ciclagem prévia) e teste de Tukey. Pode-se concluir que a ciclagem mecânica não influenciou na resistência final dos corpos-de-prova quando submetidos à carga compressiva. Além disto, verificou-se que as próteses cimentadas apresentaram maior resistência à fratura da cerâmica que as duas variações de infra-estrutura para próteses parafusadas com níveis de significância estatística (p\' < OR =\'0,5). Entre as próteses parafusadas não foram observadas diferenças estatisticamente significantes (p\' > OR = \'0,5). / In implant prosthodontics, the choice of retention system (cemented or screwed) is often related to personal preferences of each professional. However, some aspects that differenciate these 2 types of prosthesis must be considered at the time of selection: the passivity of the fit, the reversibility, the aesthetics, the occlusion and the presence of the occlusal opening of the screw-access hole. The absence of access hole is a great advantage when using cemented prosthesis especially when it comes to cases where aesthetic is a priority. In addition, the discontinuing of the ceramic in the screwed prosthesis may be a factor of weakening. This becomes even more serious when the screw-access hole is totally ceramic in order to minimize its aesthetic deficiency. The aim of this study was to evaluate the resistance to fracture of cemented and screw-retained implant-supported metalloceramic crowns with two different frameworks designs. Moreover, the influence of the aging of ceramics by mechanical cycling on the resistance to fracture under compressive load was also observed. Ten cement-retained, ten screw-retained with the screw-access hole in metal measuring 2mm height (\"chimney\") and ten screw-retained with screw-access hole in ceramic measuring 2mm height (without \"chimney\") single crowns were manufactured. All screw-retained crowns were screwed directly over the implant. Half of the specimens from each group (n=5) were subjected to Mechanical cycling. The load (100N, 1.200.000 cycles, 2 Hz) was applied by a spherical stainless steel tip (6mm in diameter) simultaneously on 4 cusps (2 buccal and 2 lingual), simulating the contact with the antagonist tooth, under water at 37oC. All specimens were subjected to axial compression with a spherical tip (6mm in diameter) in a universal testing machine at 0.5mm/min. Mean values of maximum force required to fracture were analyzed using 2-way ANOVA (1=framework, 2=mechanical cycling) and Tukey\'s test for multiple comparisons (p\' < OR =\'0,5). Mechanical cycling did not affect the strength of the specimens when subjected to compressive load. Cemented prosthesis had greater resistance to fracture than the two variations of screwed frameworks with statistically significantdifferences. Between the 2 types of screwed prosthesis no statistically significant differences were observed.

Estudou-se a caracterização de blocos sinterizados à base de Co-Cr-Mo visando a obtenção de próteses odontológicas por fresagem CAD/CAM. O processo de sinterização foi estudado e ocorreu através do transporte difusional de massa e calor no estado sólido, denominado sinterização no estado sólido. Esse fenômeno produz uma forte união entre as partículas devido ao transporte de massa, em escala atômica, sob condições controladas de tempo, temperatura e atmosfera. Foram realizadas sinterizações interrompidas a 800, 1000, 1200 e 1300°C nos tempos de 15 minutos, 1 hora e 4 horas. A liga foi caracterizada nas condições recebida e sinterizadas em termos de composição química, propriedades mecânicas e caracterização microestrutural. Para isto, utilizou-se fluorescência de raios X, dilatometria, ensaios de Arquimedes, ensaios de dureza, ensaios de compressão, microscopia eletrônica de varredura (MEV), microscopia óptica e microanálise eletrônica dispersiva (EDS). Os resultados composicionais indicam que a liga se encontrava dentro da faixa de composição química estabelecida pelo manual do fabricante e pela norma ASTM 1537. As partículas analisadas na condição pré-sinterizada exibiram formato esférico, indicando uma provável utilização de pós atomizados. A estimativa do levantamento da distribuição do tamanho das partículas foi realizado utilizando o programa de computador ImageJ, e a distribuição foi caracterizada como assimétrica positiva. O material no estado recebido se apresentou monofásico. A fase presente encontrada foi ?Co com estrutura cristalina CFC. Em contrapartida, as amostras sinterizadas apresentaram porções de fase ?Co, com estrutura cristalina hexagonal, fase esta formada a partir da transformação ?Co <-> ?Co, na qual, a energia armazenada na forma de defeitos é a força motriz da transformação. E sugere que a transformação ocorreu durante resfriamento. A amostra sinterizada por quatro horas em 1200°C apresentou-se no estágio final de sinterização, dado que os poros encontrados tinham aspecto arredondado e com densificação maior que 90%. Os resultados de compressão indicam tensão média de ruptura de 2523 ± 168 MPa. / This work studied the characterization of Co-Cr-Mo sintered blocks in order to obtain dental prosthesis by prototyping CAD/CAM. The sintering process was studied through diffusional mass transport in solid state, termed solid state sintering. This phenomenon produces a strong bond between the particles due to mass transport, at the atomic scale, under controlled conditions of time, temperature and atmosphere. The interrupted sintering was performed at 800, 1000, 1200 and 1300 ° C in times to 15 minutes, 1 hour and 4 hours. The alloy was characterized in conditions as received and sintered in terms of chemical composition, mechanical properties and microstructural characterization. For this, we used X-ray fluorescence, dilatometry, Archimedes tests, hardness tests, compression tests, scanning electron microscopy (SEM), optical microscopy and dispersive electron microanalysis (EDS). The results indicate that the alloy was within the chemical composition range established by the manufacturer and ASTM 1537. The particles analyzed in the pre-sintered condition showed spherical shape, indicating a likely use of atomized powders. The estimate of the particle size distribution was performed using ImageJ software, and the distribution is characterized as positive asymmetric. The samples in the received state were monophasic. This phase was found ?Co with FCC crystal structure. On the order hand, the sintered samples showed ?Co phase portions with hexagonal crystal structure, phase formed from the transformation ?Co <-> ?Co, in which the energy stored in the form of defects is the driving force of transformation and suggests that transformation occurred during the cooling. Sample sintered during four hours at 1200°C was in the final stages of sintering, since the pores were found aspect rounded and densification above 90%. The compression results indicate rupture stress at 2523 ± 168 MPa.

Objetivo: Considerando que a fissura labiopalatina (FLP) é uma anomalia importante em nossa realidade clínica, que os procedimentos cirúrgicos têm como objetivo restaurar a forma e a função normal das estruturas alteradas, o que muitas vezes sujeitos com esse tipo de malformação por motivos variados não podem se beneficiar dessa forma de tratamento, sendo indicados outros procedimentos, como por exemplo, a utilização de prótese de palato, o presente estudo tem como objetivos mensurar a gravidade dos sintomas de ansiedade e verificar a expectativa de sujeitos de ambos os gêneros, com disfunção velofaríngea, indicados à colocação da prótese de palato. Método: Estudo transversal e descritivo. Foram analisados 30 sujeitos, do Hospital de Reabilitação de Anomalias Craniofaciais da USP com disfunção velofaríngea, de ambos os gêneros na faixa etária de 15 a 64 anos, com idade média de 28 anos, indicados para colocação da prótese de palato, no ano de 2005. Como instrumentos foram utilizados um questionário de expectativa formulado pela própria pesquisadora e o inventário de ansiedade de Beck. Resultados/Conclusões: Ocorreu expectativa com relação à modificação da fala em todos os sujeitos; a expectativa de mudança nos aspectos profissional e afetivo foi a mais relatada; a idade e os sujeitos do gênero feminino e do masculino não foram fatores relevantes nos níveis de ansiedade; o nível mínimo de ansiedade foi o de maior ocorrência; a expectativa foi mais freqüente que a ansiedade na população amostrada. / Objective: Cleft lip and palate (CLL) is a very common craniofacial anomaly. The cleft is usually corrected with surgery which may fail resulting in velopharyngeal dysfunction (VPD). The use of palatal prosthesis is an alternative treatment for correcting both, CLP and VPD. This study evaluated anxiety symptoms expectations of subjects of both genders, with velopharyngeal dysfunction, referred to palatal prosthesis program for VPD treatment. Method: In this cross sectional and descriptive study 30 subjects with velopharyngeal dysfunction, aged 15 to 64 years old (mean age of 28) were interviewed at the Hospital for Rehabilitation of Craniofacial Anomalies (HRAC). All subjects referred to the palatal prosthesis program at HRAC in the year of 2005 were considered for participation in the study but only the first 30 candidates were included. A questionnaire addressing expectation elaborated by the researcher and the Beck Scale on anxiety were used. Results/Conclusions: All subjects showed expectation regarding speech modification. Changes in professional and affective aspects of their lives after changes in speech were obtained with palatal prosthesis were the most reported expectations. Subjects\' age and gender influenced anxiety levels significantly which were minimum across subjects. High levels of expectation were more frequent than anxiety in the sample population.

Visando melhorar a qualidade de vida dos pacientes com perdas de estrutura maxilar faz-se necessária sua reabilitação, seja ela cirúrgica ou protética por meio de próteses obturadoras, esta última, um recurso terapêutico que minimiza os distúrbios funcionais, estéticos e psicológicos. Este estudo avaliou o comportamento biomecânico de prótese obturadora maxilar Classe II de Okay retida por implantes e sistema de retenção ERA®, observando as tensões geradas no tecido gengivo-mucoso e ósseo maxilar. A Análise de Elementos Finitos foi realizada empregando-se um modelo digital desenvolvido a partir da tomografia computadorizada de um indivíduo adulto. Quatro implantes foram posicionados na maxila, em região de incisivo lateral, canino, segundo pré-molar e primeiro molar esquerdos, onde as estruturas do sistema de retenção ERA® foram posicionadas nas extremidades de uma barra metálica e convertidas para serem representadas por superfícies. Utilizou-se o programa Rhinoceros® versão 5.0 para gerar o modelo maxilar BioCAD 3D, incorporando-se os modelos CAD dos implantes, UCLAS e o CAD do sistema de retenção ERA®. O CAD do sistema ERA®, fundido em metal, foi desenvolvido a partir de imagens geradas pelo microCT SkyScan 1176 Bruke no formato BMP e TIFF. Essas imagens no formato TIFF foram exportadas para o software img2dcm, convertidas para o formato DICOM e então exportadas para o software Invesalius que reconstruiu tridimensionalmente gerando uma malha no formato STL. As estruturas finalizadas foram exportadas para software Hyperworks 13.0 e pós-processadas com a visualização de resultados pelo Hyperview, tendo sido aplicada uma força de 80N na plataforma oclusal e de 35N na plataforma incisal. Foi realizada uma análise qualitativa, correspondente à escala de máxima tensão principal e os valores quantitativos expressos em MPa. Ocorreu um deslocamento máximo da prótese obturadora na região sem suporte ósseo, tendo como fulcro a linha de ressecção óssea. Observou-se menos forças de tração do que de compressão. As forças analisadas se mostraram bastante favoráveis à estabilidade da prótese obturadora implanto-retida por se apresentarem bem distribuídas pelo tecido gengivo-mucoso e ósseo da maxila remanescente, indicando que o sistema ERA® de retenção é adequado para reabilitação maxilar das perdas ósseas Classe II de Okay. / Searching to improve quality of life of the patients that had sustained structural maxillary loss with the necessity of rehabilitation, either through surgery or obturator prosthesis, which is a therapeutic resource to minimize functional, esthetic and psychological impairments. This study evaluated the biomechanical behavior of an Okay Class II obturator prosthesis implant retained and ERA® system, analyzing the resultant stress on the soft and bone tissue. The finite element analysis was made with a digital model constructed from a computed tomography. Four implants were positioned on the left maxillae, on the following regions: lateral incisor, canine, second premolar and first molar, with the ERA® system positioned on the extremities of a metallic bar. The software used to create the BioCAD 3D model was Rhinoceros v. 5.0, including the CAD models from the implants, UCLAS and ERA® system. The ERA® CAD model was obtained from a microCT SkyScan 1176 Bruke images, on the BMP and TIFF format. The TIFF images were exported to the img2dcm software, converted in DICOM format and finally exported to the software Invesalius, were the STL mesh was created. All mesh were imported into the software Hyperworks v. 13.0 and the post-processing was visualized on Hyperview. The force applied was of 80N over the occlusal platform and of 35N over the incisal platform. A quantitative analysis was performed, corresponding to the maximum main stress, expressed in MPa. The obturator prosthesis suffered its maximum dislocation on the region with no bone support, with the bone resection line as fulcrum. Less tension forces were observed, when comparing to compression. The forces observed were favorable to maintain the implant retained prosthesis stabilization, with good distribution over the soft and bone tissues, suggesting that the ERA® retention system is suitable to Okay Class II maxillary bone loss.

Do planejamento à execução da prótese mucosa-dento-suportada, a literatura apresenta trabalhos que aponta m as dificuldades do desempenho de uma prótese que se relaciona com tecidos de comportamentos distintos, dente e fibromucosa. Estes trabalhos abordam os problemas biomecânicos e os prejuízos que sofrem o osso e os dentes, sob pressão, durante a mastigação, bem como as dificuldades de distribuição das cargas sobre os tecidos bucais no movimento ocluso-gengival. Porém, essa prótese também sofre forças de tração, por diversas situações clínicas, as quais levam a sela a se deslocar da fibromucosa num movimento gêngivo-oclusal. O objeto desta pesquisa foi desenvolver e testar, em laboratório, um método que possibilitasse à prótese mucosa-dento-suportada dispor de maior retenção na região da fibromucosa, reduzindo o movimento gêngivo-oclusal, e conferindo maior estabilidade à prótese e conforto ao paciente. Para realizar o experimento , foi construída uma base acrílica modificada, correspondente à sela da prótese, com uma canaleta na região que contata a fibromucosa. Esta canaleta foi preenchida com reembasador macio para prótese, à base de silicone. Em seguida, a base foi reembasada no modelo resiliente, especialmente construído para simular a fibromucosa. Uma haste metálica foi fixada em suas extremidades, sendo uma à base acrílica, e a outra extremidade fixada ao mandril do equipamento utilizado para o tracionamento (Versa-Test). Estando a base posicionada sobre o modelo, foram realizados os movimentos de pressão e de tração. A avaliação dos testes foi realizada na base acrílica convencional (sem canaleta) e na base acrílica modificada, cujos valores foram registrados em newton. As bases acrílicas sobre os modelos eram imersas em óleo vegetal, devido ao necessário meio viscoso, com tensão superficial, possibilitando os fenômenos de adesão. Os resultados demonstraram que, na presença de silicone, foi necessária força de tração maior e estatisticamente significante para remover a base do modelo, em relação à base sem silicone. / From the planning to the execution of the tissue-dento-supported prosthesis, the literature presents a range of works standing out the difficulties related to the prosthesis performance when facing distinctive tissues, tooth and fibromucous. These works approach the biomechanical problems and the damages suffered by osseous tissues and teeth under pressure, during the mastication, as well as the difficulties of distribution of the loads on oral tissues in the oclusal-gengival movements. However, this prosthesis also suffers traction forces, in several clinical situations, leading the saddle to move of the fibromucous in a gengival-occlusal movement. The aim of this research was to develop and to test, in a laboratory, a method to improve the tissue-dento-supported prosthesis retention in the fibromucous area reducing the gengival-occlusal movement and allowing a larger stability to the prosthesis and comfort to the patient. In order to accomplish the experiment, a modified acrylic base was confectioned, corresponding to the saddle of the prosthesis and constituted by a small channel in the fibromucous contact area. This channel was filled out with soft reliner for prosthesis, silicon composed. Afterwards, the base was rebased in the resilient model, especially confectioned to simulate the fibromucous. A metallic stem was fixed in two extremities, being one to the acrylic base, and other extremity fixed to the equipment arbor used for the traction (Versa-Test). With the base positioned on the model, the pressure movements and traction were accomplished. The evaluation of the tests was accomplished in the conventional acrylic base (without channel) and in the modified acrylic base, whose values were registered in Newton. The acrylic bases on the models were immersed in the vegetable oil, due to the necessary viscous condition, with superficial tension, making possible the adhesion phenomena. The results demonstrated that in the presence of silicon was necessary a larger and statistically significant traction force to remove the base of the model in relation to the base without silicon.