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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.
801

Avaliação de dois diferentes planejamentos de próteses totais fixas implantossuportadas, comparando as técnicas de fabricação das infraestruturas: tecnologia CAD-CAM, fundição convencional e barra articulada / Evaluation of two different designs of full-arch implant-supported fixed dentures, comparing the infrastructure manufacturing techniques: CAD-CAM technology, conventional casting and Articulated Bar

Silva, Rafael Cândido Pedroso e 27 January 2016 (has links)
O objetivo deste estudo foi avaliar dois diferentes planejamentos de próteses totais fixas implantossuportadas, comparando as técnicas de fabricação das infraestruturas: tecnologia CAD-CAM, fundição convencional e Barra Articulada. Após ciclagem termomecânica, foram analisadas a perda de torque dos parafusos protéticos e adaptação marginal vertical e horizontal. Ao final, as próteses foram submetidas a ensaios de fadiga acelerada progressiva e resistência à fratura. Foram confeccionadas 48 próteses totais fixas implantossuportadas, as quais foram divididas inicialmente em dois grupos, G1 protocolo convencional; G2 - &ldquo;All-on-4&rdquo;. De acordo com a técnica de fabricação das infraestruturas, estes grupos foram divididos em três subgrupos, A - tecnologia CAD-CAM; B - fundição convencional; C - Barra Articulada, proporcionando seis amostragens diferentes: G1A, G1B, G1C, G2A, G2B e G2C (n=8). Todas as próteses foram avaliadas em relação à adaptação marginal vertical e horizontal, utilizando MicroCT, antes e após a ciclagem termomecânica (2.000.000 de ciclos). A perda de torque dos parafusos protéticos foi analisada antes (T0), após 1.000.000 (T1) e 2.000.000 de ciclos (T2). Após este ensaio, as próteses foram submetidas ao teste de fadiga acelerada progressiva (n=8) e em sequência, ensaio de resistência à fratura (n=6). A perda de torque teve diferença significante para todos os tempos comparados (p<0,01), exceto em G2B, onde a comparação entre T1 - T2 não mostrou diferença significante (p=0,72). A comparação entre G1 e G2 não foi significante. A comparação entre os subgrupos A, B e C teve diferenças significantes em G1T1, G1T2, G2T1 e G2T2 quando comparados os subgrupos A - B e B - C, todos com (p<0,01). Não houve diferenças significantes para a adaptação marginal vertical e horizontal antes e depois da ciclagem em todos os grupos. Na comparação de G1 e G2, houve diferença significante para a adaptação vertical e horizontal apenas no subgrupo B, nos dois tempos, ambos com (p <0,01). Na comparação dos subgrupos A, B e C, houve diferenças significantes em G1 antes e depois; e G2 antes e depois, quando comparados os subgrupos A - B e B - C, todos com (p<0,01) para a adaptação vertical e horizontal. Já para a adaptação horizontal, esta comparação foi significante apenas em G2 antes e depois, ambos com (p=0,02). Em relação à resistência à fratura, a comparação entre G1 e G2, foi significante em todos os subgrupos, A e C (p<0,01), B (p=0,02). A comparação dos subgrupos A, B e C, também foi significante em relação à resistência à fratura das próteses em todos os grupos (p<0,01). Pode-se concluir que a simulação de ciclos mastigatórios teve influência significante sobre a perda de torque dos parafusos protéticos, porém não influenciou significativamente a adaptação marginal vertical e horizontal das próteses; desadaptações marginais influenciaram significativamente no afrouxamento dos parafusos protéticos; as próteses dos subgrupos A e C obtiveram resultados significantemente melhores para a adaptação marginal vertical e horizontal quando comparadas às do subgrupo B, sendo que na adaptação horizontal, as do subgrupo A tiveram resultados melhores que as do C; a quantidade e distribuição dos implantes não influenciou na perda de torque dos parafusos protéticos em todas as situações, porém teve influência significativa na adaptação marginal vertical e horizontal das próteses do subgrupo B; todas as próteses sobreviveram ao ensaio de fadiga acelerada progressiva; em relação ao ensaio de resistência à fratura, as próteses do G2, tiveram resultados significantemente melhores que as do G1, o subgrupo B obteve valores significantemente maiores de resistência na região do cantilever, quando comparadas ao subgrupos A e C; o subgrupo A obteve os menores valores de resistência. / The objective of this study was evaluate two different designs of full-arch implant-supported fixed dentures, comparing the infrastructure manufacturing techniques: CAD-CAM technology, conventional casting and Articulated Bar. After thermomechanical cycling, were analyzed prosthetic screws loosening and vertical and horizontal marginal adaptation. In the end, the prostheses were submitted to tests of progressive accelerated fatigue and fracture resistance. Were made 48 implant-supported fixed dentures, which initially were divided into two groups, G1 - conventional protocol; G2 - \"All-on-4\". According to the technique of manufacturing infrastructure, these groups were divided into three subgroups: A - CAD-CAM technology; B - conventional casting; C - Articulated bar, providing six different samples: G1A, G1B, G1C, G2A, G2B e G2C (n=8). All samples were evaluated in the vertical and horizontal marginal adaptation using MicroCT before and after the thermomechanical cycling (2,000,000 cycles). The loosening of the prosthetic screws was analyzed before (T0), 1,000,000 (T1) and 2,000,000 cycles (T2). After this test, the prostheses were submitted to progressive accelerated fatigue test (n = 8) and sequentially fracture resistance test (n = 6). The prosthetic screw loosening has significant difference for all time compared (p <0.01), except in G2B where the comparison between T1 - T2 showed no significant difference (p = 0.72). The comparison between G1 and G2 was not significant. The comparison between subgroups A, B and C had significant differences in G1T1, G1T2, G2T1 and G2T2 compared subgroups A - B, B - C, all of (p <0.01). There were no significant differences for vertical and horizontal marginal adaptation before and after cycling in all groups. Compared to G1 and G2, there was a significant difference for vertical and horizontal adjustment only in the subgroup B in two stages, both (p <0.01). In the comparison of subgroups A, B and C, there were significant differences G1 before and after; and G2 before and after, when compared subgroups A - B, B - C, all of (p <0.01) for vertical and horizontal adaptation. As for the horizontal adaptation, this comparison was significant only in G2 before and after, with both (p = 0.02). With regard to fracture resistance, the comparison between G1 and G2 was significant in all subgroups, A and C (p <0.01), B (p = 0.02). The comparison of subgroups A, B and C was also significant compared to the fracture resistance of the prosthesis in all groups (p <0.01). It can be concluded that the simulation of mechanical cycling had significant influence on the loosening of prosthetic screws, but did not significantly influence the vertical and horizontal marginal fit of the prosthesis; marginal adaptation significantly influenced the loosening of prosthetic screws; the prostheses of the subgroups A and C had significantly better results for the vertical and horizontal marginal adaptation when compared to the subgroup B, and in the horizontal adaptation, the sub-group A had better results than those of C; the amount and distribution of the implants did not affect the prosthetic screws loosening in all situations, but had significantly influence in vertical and horizontal marginal adaptation of subgroup B prostheses; all samples survived in progressive accelerated fatigue test; in relation to the fracture resistance test, the prosthesis G2, had significantly better results than the G1, the B subgroup achieved significantly higher values of resistance in the cantilever region, when compared to subgroups A and C; the subgroup C obtained the smallest resistance.
802

Printed circuit board computer-aided design in Hong Kong.

January 1987 (has links)
by Mok Chun-Hung. / Thesis (M.B.A.)--Chinese University of Hong Kong, 1987. / Bibliography: leaves 72-75.
803

Marketing of technology-based products: a case study of CAD/CAM software companies in Hong Kong.

January 1995 (has links)
by Tsang Tze-kon. / Thesis (M.B.A.)--Chinese University of Hong Kong, 1995. / Includes bibliographical references (leaves 50-51). / ABSTRACT --- p.iii / TABLE OF CONTENTS --- p.v / ACKNOWLEDGEMENT --- p.vii / CHAPTER / Chapter 1. --- INTRODUCTION / Chapter 1.1 --- Technology-based Products --- p.1 / Chapter 1.2 --- Computer-Aided Design & Computer-Aided Manufacturing (CAD/CAM) --- p.2 / Chapter 1.3 --- Research Objectives --- p.3 / Chapter 2. --- LITERATURE REVIEW / Chapter 2.1 --- Characteristics of High-Technology Market --- p.4 / Chapter 2.2 --- Non-technical Approach to Marketing High-Tech --- p.5 / Chapter 2.3 --- Importance of Pre-Sale & Post-Sale Services --- p.7 / Chapter 2.4 --- Technical Life Cycle --- p.7 / Chapter 2.5 --- Innovation-Driven versus Market-Driven --- p.9 / Chapter 2.6 --- Product Positioning of Technology-based Products --- p.10 / Chapter 2.7 --- Country -of- Origin Issue --- p.12 / Chapter 3. --- RESEARCH METHODOLOGY / Chapter 3.1 --- Exploratory Research --- p.14 / Chapter 3.2 --- Descriptive Research --- p.14 / Chapter 4. --- FINDINGS / Chapter 4.1 --- Case Studies --- p.16 / Chapter 4.1.1 --- Company C / Chapter 4.1.2 --- Prima Design System Ltd. / Chapter 4.1.3 --- Splineware Graphics Systems Co. Ltd. / Chapter 4.2 --- Findings of Survey & Data Analysis --- p.29 / Chapter 4.2.1 --- Sample Characteristics / Chapter 4.2.2 --- Factors Affecting Buying Decision / Chapter 4.2.3 --- Country -of- Origin Issue / Chapter 5. --- DISCUSSION / Chapter 5.1 --- Marketing Strategy of Company C --- p.31 / Chapter 5.2 --- Marketing Strategy of Prima Design Systems Ltd. --- p.33 / Chapter 5.3 --- Marketing Strategy of Splineware Graphics Systems Co. Ltd. --- p.35 / Chapter 5.4 --- Role of the Hong Kong Industrial Technology Centre Corporation --- p.36 / Chapter 5.5 --- Limitations of Case Studies --- p.37 / Chapter 5.6 --- Limitations of Questionnaire Survey --- p.38 / Chapter 5.7 --- Country-of-Origin Issue --- p.39 / Chapter 5.8 --- Future of Technology-based Companies in Hong Kong --- p.40 / Chapter 6. --- RECOMMENDATIONS & CONCLUSIONS / Chapter 6.1 --- Recommendations --- p.42 / Chapter 6.2 --- Conclusions --- p.43 / APPENDICES / Appendix A: Questionnaire for Case Study --- p.44 / Appendix B: Questionnaire for Descriptive Research --- p.46 / Appendix C: Survey Findings --- p.48 / BIBLIOGRAPHY --- p.50
804

Study of Fixturing Accessibilities in Computer-Aided Fixture Design

Ghatpande, Puja Sudhakar 08 August 2008 (has links)
"Fixtures form an important factor in traditional and modern flexible manufacturing systems, since fixture design directly affects manufacturing quality and productivity. Hence, it is necessary to evaluate quality of fixture design. The fixturing accessibility refers to machining feature accessibility and loading /unloading accessibility. The development of Computer Aided Fixture Design (CAFD) has simplified this task. Fixture design activities include setup planning, fixture planning and fixture configuration design. Fixture design verification comes next. Fixturing accessibility using Computer Aided Fixture Design is part of the verification process and has not received much attention till date. Machining feature accessibility analysis involves the evaluation of possible interference between fixture components and the cutting tool, which moves with pre-programmed tool path, while the loading and unloading accessibility relates to the ease with which the operator attaches/detaches the workpiece from the surrounding manufacturing environment. This research has three main focuses. The first focus is to evaluate machining feature accessibility, by integrating fixture designs in SolidWorks and the NC programming in Esprit. The main goals are evaluation of fixture design for any kind of interference between tool/workpiece/fixtures and enable Esprit to indicate interference, if any. The next step is to modify the fixture design accordingly and thus, finally obtain an interference free fixture design by reiteration. The second and third focuses deal with analysis of loading and unloading accessibility. A simulation based approach is applied to evaluate loading/unloading paths for different workpiece-fixture setups and checking interference in a dynamic mode. Then the third focus is to develop analysis method and criteria of comparisons of fixturing accessibility in different fixture designs. Thus, this research establishes methods of analysis for accessibilities in fixture design. Also, the guidelines for good fixture design will prove to be of great use to both, the beginners as well as the experienced fixture designers in this field. "
805

Desenvolvimento de novas técnicas para redução de falso-positivo e definição automática de parâmetros em esquemas de diagnóstico auxiliado por computador em mamografia / Development of news technique for reduction of false-positive and automatic definition of parameters of mammograms for CAD schemes

Martinez, Ana Cláudia 28 September 2007 (has links)
O presente trabalho consiste na investigação das características da imagem mamográfica digitalizada para definir automaticamente parâmetros de processamento em um esquema de diagnóstico auxiliado por computador (CAD) para mamografia, com o objetivo de se obter o melhor desempenho possível. Além disso, com base na aplicação dos resultados dessa primeira investigação, propõe-se também uma técnica de redução dos índices de falso-positivo em esquemas CAD visando à redução do número de biópsias desnecessárias. Para a definição automática dos parâmetros de processamento nas técnicas de detecção de microcalcificações e nódulos, foram extraídas algumas características das imagens, como desvio padrão, terceiro momento e o limiar de binarização. Utilizando o método de automatização proposto, observou-se um aumento de 20% no desempenho do esquema CAD (Az da curva ROC) em relação ao método não automatizado com parâmetro fixo. Para que fosse possível o processamento da imagem mamográfica inteira pelo esquema CAD e as técnicas desenvolvidas, foi desenvolvida também uma técnica para seleção automática de regiões de interesses, que recorta partes relevantes da mama para a segmentação. O índice de falsos positivos foi tratado por técnica específica desenvolvida com base na comparação das duas incidências típicas do exame mamográfico que, juntamente com a avaliação automática da imagem no pré-processamento para detecção de microcalcificações produziu uma redução significativa de 86% daquela taxa em relação ao procedimento de parâmetro fixo. / This present work consists on the investigation of mammographic image characteristics for automatic determination of image processing parameters for a mammography computer aided diagnosis scheme (CAD) in order to get optimal performance. Additionally, using the results obtained on this first investigation, it was also developed a new technique for the reduction of false-positive rates on CAD projects, which can result on the reduction of the number of unnecessary biopsies. For the automatic definition of the image processing parameters for the techniques of detection of microcalcifications and nodules, some image characteristics had been extracted, as standard deviation, third momentum and the thresholding value. Using the proposed automatization method it was reported an increase of 20% in the CAD performance (evaluated determining the ROC curve) in comparison to the non-automatic method (fixed parameter). Besides, for CAD schemes it is necessary to process the entire mammographic image. Thus, it was also developed a technique for automatic selection of regions of interests in the mammogram, which extracts better regions from breast image for further segmentation. False-positives rates was treated by a specific technique based on the comparison of the two typical incidences of mammographic examination that together with the automatic parameter determination method for microcalcification detection produced a significant reduction of 86% of that rate in relation to the procedure that uses fixed parameter.
806

Gerente de configurações para o ambiente STAR / Configuration manager to STAR framework

Ribeiro, Helena Grazziotin January 1993 (has links)
Este trabalho apresenta os mecanismos de gerencia de configurações para o ambiente STAR. STAR é uma plataforma para o desenvolvimento de ambientes para projetos de circuitos e sistemas eletrônicos que está sendo desenvolvido na Universidade Federal do Rio Grande do Sul em cooperação com o Centro Científico da IBM no Rio de Janeiro. Seus objetos de projeto caracterizam-se como sistemas complexos e são representados através de um modelo de dados hierárquico, que tem por base a composição de objetos. Para expressar a evolução dos objetos de projeto no tempo utiliza-se versões, que mantêm as descrições dos objetos num determinado instante de tempo. O mecanismo de gerência de versões é fortemente relacionado à representação dos dados, suportando as diferentes dimensões que essa representação permite: visões, alternativas e revisões. A utilização de versões associada à composição de objetos faz com que se possa ter diversas possibilidades de descrição para um mesmo sistema complexo, em função da combinação das versões. Para que se possa submeter um objeto de projeto a uma ferramenta, como um simulador, épreciso selecionar versões de modo a obter uma descrição única, que é a sua configuração. A existência de um gerente de configurações dá agilidade a essa tarefa, pois ele oferece recursos para facilitar e tornar mais rápida a construção de configurações, através de manipulação e consultas a informações obtidas junto ao ambiente sobre os objetos de projeto. As configurações no STAR são determinadas a partir do atributo de referência dos componentes ou através da definição de um objeto - configuração. O gerente de configurações proposto para o ambiente neste trabalho suporta o estabelecimento de configurações estáticas, dinâmicas e abertas. Elas podem ser estabelecidas manualmente, através de escolhas do usuário, automaticamente, através da escolha entre um dos critérios pré-estabelecidos, ou de modo semi-automático, através da definição de uma expressão de configuração. Os critérios pré-estabelecidos têm por base a versão corrente e a versão mais recente. A utilização de expressões de configuração permite que se selecione versões com mais objetividade, uma vez que sua construção é feita a partir de características dos objetos, dadas por seus atributos, que permitem restringir as versões selecionadas àquelas cujas características são desejadas. A linguagem que permite a definição de expressões de configuração é um dos recursos estabelecidos que facilitam a tarefa do usuário. Outro recurso provido é a possibilidade de armazenar configurações. Isso torna possível sua reutilização em outros momentos e também por outros objetos, e preserva a flexibilidade de mantê-las como dinâmicas, ou abertas, apesar de já ter-se escolhido versões para complementá-las. Para tanto, tem-se como parte do modelo de dados os objetos-configuração, sobre os quais foram estabelecidas operações de criação, alteração, cópia, remoção, consulta e escolha de objetos. O funcionamento destas operações é a base do processo de configuração. / This work presents the mechanisms for configuration management in the STAR framework. STAR is an electronic design automation framework, under development at the University of Rio Grande do Sul in cooperation with the IBM Rio Scientific Center at Rio de Janeiro, Brazil. The design objects supported are complex systems and they are represented through a hierarchical data model. Versions are used to express the evolution process of design objects. The version management mechanism developed is strongly related with the data representation, and it supports the different dimensions of versions: views, alternatives and revisions. The use of versions associated with composite objects allows the existence of many possibilities of description for the same complex system, as a consequence of different versions combination. When submitting a design object to a design tool, like a simulator, it is necessary to select versions for components in order to obtain a single object description, called the object configuration. A configuration manager offers resources, as manipulation and query on design objects in the framework, to make version selection in configuration construction easy and fast. STAR configurations are established through component reference attributes or through a configuration object definition. The configuration management mechanism developed for the STAR framework in this work supports static, dynamic and open configurations. They are established in a manual, automatic or semi-automatic way. In the manual way, the user is responsible for choosing the selected versions. In the automatic way, it is possible to choose between the current version and the most recent version, which are pre-defined criteria. The user can define and use configuration expressions in a semi-automatic way. These expressions make the version selection objective, due to use of objects attributes, representing objects characteristics in the expression. The use of configuration expressions allows the selection of versions with specific characteristics. A language is available for the definition of configuration expressions. The possibility to store configurations is provided. Configurations may be reused in another time and by other objects. The possibility to store configurations allows them remain either dynamic or open, even if the choose of versions to complement them had been done. To make this possible, configuration objects are integrated in the data model. Operations on configuration objects are: create, update, copy, delete, query and select. These operations are the basis of the configuration process.
807

Comparative assessment of conventional vs. CAD/CAM complete denture fabrication techniques on patient satisfaction, quality of life and prosthesis biofilm

Jia-mahasap, Wissanee 01 May 2017 (has links)
Objectives: The primary objective was to assess the impact of two denture fabrication techniques, conventional and CAD/CAM, on oral health-related quality of life (OHRQoL) and patient satisfaction in complete denture wearers. The secondary objective was to compare the level of microorganisms present on complete dentures from the two fabrication techniques. Methods: Twenty-eight completely edentulous subjects (16 men and 21 women, age range from 49 to 87 years old.), who had been edentulous for at least 6 months, were wearing ill-fitting complete dentures, or unsatisfied with their existing complete dentures were recruited. Subjects were randomized to conventional and computer-aided design/ computer-aided manufacturing (CAD/CAM) treatment groups. Subjects in both groups were given the OHIP-EDENT (Oral Health Impact Profile for Edentulous Patients) and patient satisfaction questionnaires to record the data at baseline and at 1 month post-delivery of the new prostheses. Plaque samples were collected from intaglio surfaces of maxillary complete dentures at 1 month post-delivery to culture for any colonization of bacteria and/or yeasts. Results: There was a significant reduction in OHIP-EDENT scores within both treatment groups at the 1 month follow-up (p < 0.05). There was also a significant reduction in almost all OHIP-EDENT domains scores at 1 month. Gender was significantly associated with OHIP-EDENT score at baseline (p = 0.0419) and at 1 month (p = 0.0152). Female subjects tend to have higher OHIP-EDENT scores than male subjects. There was no significant difference in patient satisfaction between treatment groups both at baseline and at the 1 month visit for almost all aspects of satisfaction (p> 0.05). Appearance of maxillary denture was the only significant difference in patient satisfaction across treatment groups (p = 0.0213). The comparisons of microbial counts showed no significant difference between treatment groups. Conclusions: There were no significant difference on oral health-related quality of life (OHRQoL) and patient satisfaction between two treatment groups at baseline and 1 month. There was no significant difference in microbial counts between two treatment groups.
808

Desenvolvimento de uma técnica de desenho digital e impressão em 3D de placas oclusais e sua aplicabilidade no tratamento de pacientes com disfunção temporomandibular / Development of a technique of digital design and 3D printing of occlusal splints and its applicability in the treatment of patients with temporomandibular disorders

Vasques, Mayra Torres 11 December 2018 (has links)
O uso de novas tecnologias na odontologia, como a técnica CAD/CAM, promete ser uma opção relevante no que diz respeito à confecção das placas oclusais, empregadas no tratamento de disfunções temporomandibulares. O objetivo desta pesquisa foi desenvolver uma técnica para desenho e confecção de placas oclusais pelo método CAD/CAM, em impressora 3D, e verificar seus resultados clínicos no tratamento de pacientes com disfunções temporomandibulares. Para o desenho das placas foi desenvolvida uma metodologia de desenho digital (CAD), utilizando o software Meshmixer® (Autodesk, USA), e de registro das relações maxilo-mandibulares. A partir dessa metodologia iniciou-se um estudo clínico randomizado comparativo entre as placas CAD/CAM produzidas em impressora 3D e placas produzidas convencionalmente em laboratório. O estudo foi realizado em duas etapas, 18 pacientes foram avaliados de acordo com os critérios de inclusão e exclusão. Na Etapa 1 (n=18) foram realizados testes técnicos comparativos das duas placas em relação à dor, por meio da Escala Visual Analógica; atividade muscular; ajuste interno; báscula; conforto; tempo de instalação; pontos de contato oclusal. Todos os pacientes da amostra utilizaram os dois tipos de placas. Na Etapa 2, estes pacientes foram divididos randomicamente em dois grupos para o estudo clínico randomizado (estudo cego): Grupo IMP (n=9) (placas impressas) e grupo LAB (n=9) (placas convencionais laboratoriais). Os grupos foram avaliados após 1 mês de uso, por meio dos Questionários, RDC/TMD, SF-36, escala visual de dor EVA, e pelos pontos de contato oclusais. Os dados foram avaliados estatisticamente usando os testes de Wilcoxon, de Mann-Whitney, e de Kruskal-Wallis nas análises quantitativas; os testes Qui-Quadrado e Exato de Fisher, nas variáveis categóricas. Os resultados mostraram que houve diferenças significativas (P-valor<0.05) nas avaliações para conforto, ajuste interno e tempo de confecção das placas, a favor das placas impressas. Nas demais avaliações, os grupos foram equivalentes (não- significantes). Concluiu-se que foi possível desenvolver uma técnica para desenho e confecção de placas oclusais pelo método CAD/CAM, em impressora 3D, e que o desempenho clínico foi equivalente entre as placas convencionais e impressas, sendo que estas se mostraram superiores quanto ao conforto e quanto à adaptação da superfície interna da placa, mostrando ser este um método possível e viável economicamente. / The use of new technologies in dentistry, as the CAD/CAM technique, promises to be a relevant option concerning the manufacture of occlusal splints for temporomandibular disorders treatment. The aim of this research was to develop a technique for design and manufacture occlusal splints using the CAD/CAM method and 3D printer and verify the clinical results in the treatment of temporomandibular disorders patients. It was developed a technique for occlusal splint design a using the software Meshmixer® (Autodesk, USA) and a technique to register the jaws relationship. From this method, it was started a Randomized Clinical Trial (RCT) to compare splints made through the CAD/CAM technique and others made conventionally in a dental lab. The study was performed in two steps, 18 patients were selected based on the inclusion/exclusion criteria. In Step 1 (n=18) patients were comparatively evaluated, using both splints, in relation to pain, using the visual analog scale; internal adjustment of the splint; patients comfort; time spent to deliver the appliance and occlusal contacts pattern. In Step 2, these patients were allocated in two groups (n=9 each group) randomly to the RCT be performed (blind study): Group IMP - printed splints and Group LAB (conventional lab splints). Both groups were assessed after 1 month using the splint using RDC/TMD and SF-36 questionnaires, the visual analog scale for pain, and occlusal contacts pattern. The data were statistically evaluated using Wilcoxon, Mann-Whitney, and Kruskal-Wallis test for qualitative analyses and Qui-square and Fisher´s exact tests for categorical variables. The results showed significant statistical differences (p-value<0.05) in favor of printed occlusal splints, related to patients\' comfort, internal adjustment, and time spent to deliver the appliance. All other assessments were equivalents (not significant). It was concluded that it was possible to develop a technique to design and manufacture occlusal splints using CAD/CAM and 3D printer, and furthermore the clinical performance was equivalent comparing conventional and printed occlusal splints, being the printed splints superior to conventional splints in relation to comfort and internal adjustment, proving this is a possible and economically viable method.
809

Utveckling av en universell laddare / Development of a universal charger

Sahlberg, Mikael January 2007 (has links)
Syftet med examensarbetet har varit att undersöka möjligheterna att utveckla, producera och lansera en ny universell laddare. Målet har varit att kunna ladda så många modeller av så många produkter som möjligt, vilket innefattar mobiltelefoner, kameror, datorer och MP3-spelare etc. Arbetet skulle leda fram till ett förslag på produkt. Genom att undersöka befintliga patent och produkter, har marknaden granskats och slutsatsen är att det finns en uppsjö av universella laddare på marknaden. Dock finns det få produkter som inger säkerhet, möjliggör multipel laddning och som är stationära. Dessa egenskaper blev grundstenar i den kravspecifikation som utarbetades. Genom en teknisk analys och kundundersökning sammanställdes ytterligare viktiga parametrar. Resultatet blev en stationär produkt som kan ladda både en bärbar dator och flera mindre elektroniska produkter. Genom att använda en metod som i rapporten betecknas tappteknik kan rätt laddningsförhållande garanteras. Med hjälp av en mikroprocessor och produktspecifika tappar eller ändadaptrar kan laddning av i princip alla sorters produkter och modeller ske. Arbetet har även innefattat konstruktion, CAD och prototypframtagning. / The purpose with this thesis work has been to investigate the possibilities to develop, manufacture and introduce a new universal charger. The aim has been to be able to charge as many models of as many different products as possible, including cell phones, cameras, laptops, MP3-players etc. The work would lead to a product proposal. By an examination of existing patents and products, has the market been reviewed. The conclusion is that there already are big amount of universal chargers in the international market. Yet there are only a few products that inspire safety, have a multiple charging function and which are for stationary use. Those properties became fundamentals in the specification. With a technical analyse and a customary review were more parameters included. The result is a stationary product that can be used to charge both a laptop and several smaller electronic products. By using a method that is called tip technology can the right charging conditions be guaranteed. With a micro processor and with tips which are specific for each product can mostly all sorts of products and models be charged. The work has also included mechanical design, CAD and the build of a prototype.
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Vergleichende Untersuchung von intraoraler und extraoraler Digitalisierung nach Modellherstellung mit CEREC-3D® / Accuracy of Intraoral Data Acquisition in comparison to the conventional Impression and conventional impression taking compared to intraoral digitizing

Loos, Rene 04 February 2009 (has links) (PDF)
Durch den Einsatz von CAD/CAM-Technologien sollen potenzielle Fehlerquellen der handwerklich-manuellen Herstellung zahnmedizinischprothetischer Restaurationen eliminiert werden. Grundlage für die Fertigung einer prothetischen Restauration mittels CAD/CAM ist eine möglichst genaue Digitalisierung der klinischen Situation. In dieser Studie wurde die Genauigkeit der digitalen Erfassung von Zähnen unter experimentellen sowie unter klinischen Bedingungen mit dem CEREC-3D® System (intraoral) im Vergleich zu konventioneller Abformung und Modellerstellung mit anschließender extraoraler Digitalisierung (Digiscan) untersucht. Von einem Schulungsmodell wurde mit einer Doppelmischabformung ein Modell mit präpariertem Zahn 16 erzeugt und extraoral digitalisiert. Dieses Modell wurde simuliert intraoral sowie nach erneuter Abformung und Modellherstellung extraoral digitalisiert. Im Anschluss daran erfolgte die Zuordnung der einzelnen Datensätze auf das Referenz-CAD-Modell und die dreidimensionale Differenzberechnung. Die durch die Ethik-Kommission genehmigte klinische Studie umfasste zehn Probanden. Bei diesen zehn Probanden erfolgte eine konventionelle und optische Abformung des Oberkiefers. Aus der konventionellen Abformung entstand ein Modell, welches extraoral-optisch digitalisiert wurde. Diesen Daten wurde die optische Abformung zugeordnet. Die dreidimensionale Auswertung erfolgte analog der in-vitro Studie. Die Auswertung der in-vitro Daten lieferte mittlere dreidimensionale Abweichungen von ±17-35μm bei der Betrachtung vom präparierten Zahn 16 und seinen Nachbarzähnen. Betrachtete man nur den präparierten Zahn 16, zeigten sich mittlere Abweichungen um ±17μm. Im Vergleich dazu lag die berechnete mittlere Differenz bei der intraoralen Digitalisierung eines Quadranten mit ±26-81μm erheblich darüber. Im Registrierzentrum konnte die geringste Abweichung gefunden werden. Der konventionelle Verfahrensweg (Abformung – Modellherstellung – extraorale Digitalisierung) hingegen liefert eine Genauigkeit von ±9-19μm. Anhand der gewonnenen Ergebnisse kann man sagen, dass die CEREC-3D®Kamera für die Erfassung von Einzelzahnrestaurationen sowie gegebenenfalls kleinerer mehrspanniger Restaurationen geeignet ist. Größere Restaurationen hingegen übersteigen den Indikationsbereich des Systems und sollten extraoral über den Umweg einer Abformung digitalisiert werden. Klinische Parameter beeinflussen die Genauigkeit der intraoralen Digitalisierung in einem akzeptablen Maß. Dies wird anhand des Vergleiches der in-vitro mit den in-vivo Daten ersichtlich. Dabei ist die Puderschicht von durchschnittlich 28,6μm (51) bei der intraoralen Digitalisierung zu berücksichtigen. / Using CAD/CAM-technology in dentistry is supposed to reduce or eliminate potential sources of error resulting from the manual craftsmanship needed when making dental restorative restorations. For any CAD/CAM-made restoration, a digitalization as precise as possible is basic. In this study, the precision of the digital measurement of teeth was examined in-vitro and invivo. The intraoral CEREC-3D® system was compared with conventional impression taking and model making and subsequent digitalization (Digiscan). A one-stage putty-and-wash impression was taken from a training model. The first upper molar in this model was prepared for a full crown. The resulting gypsum model was extraorally digitized. This master model was digitized with simulated intraoral digitizing and, after taking again an impression and making a gypsum model, with extraoral digitizing. The data was then aligned to the reference CAD-model, and the threedimensional differences were calculated. The clinical trial included ten probands and was approved by the responsible ethical committee. From each proband, a conventional impression as well as an intraoral digitizing was made from the upper jaw. The gypsum model resulting from the impression was digitized extraorally, and the data was aligned to the data-sets of the intraoral digitizing. The threedimensional differences were calculated analogous to the in-vitro analysis. The threedimensional analysis showed mean differences between ±17 and 35 microns for the prepared tooth 16 and its neighboring teeth. Looking at tooth 16 alone, the mean differences were around ±17 microns. Compared to these values, the mean differences calculated for intraoral digitizing of a whole quadrant were considerably higher (±26-81 microns). The smallest mean deviations were found at the center of alignment. The conventional method (impression taking - model making - extraoral digitizing) showed a significantly higher precision (±9-19 microns). The results show that the CEREC-3D®camera is suitable for single tooth and short-span restorations. However, the indication is not given for long-span restorations using the intraoral system. Such restorations should always be made after conventional impression taking, model making and subsequent extraoral digitizing. The precision of the intraoral digitizing is influenced by clinical parameters in an acceptable way as shown by the comparison of invitro and in-vivo data. The powder-layer of average 28.6 microns (51) has to be taken into consideration, when using intraoral digitizing.

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