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

An?lise biomec?nica de diferentes dimens?es de pr?teses temporomandibulares personalizadas: um estudo de elementos finitos

Rodrigues, Yriu Louren?o 29 September 2017 (has links)
Submitted by Automa??o e Estat?stica (sst@bczm.ufrn.br) on 2018-03-12T20:18:44Z No. of bitstreams: 1 YriuLourencoRodrigues_DISSERT.pdf: 2562345 bytes, checksum: 91fc4e0062ca0529e47b9cfb3eaa735a (MD5) / Approved for entry into archive by Arlan Eloi Leite Silva (eloihistoriador@yahoo.com.br) on 2018-03-16T19:57:58Z (GMT) No. of bitstreams: 1 YriuLourencoRodrigues_DISSERT.pdf: 2562345 bytes, checksum: 91fc4e0062ca0529e47b9cfb3eaa735a (MD5) / Made available in DSpace on 2018-03-16T19:57:58Z (GMT). No. of bitstreams: 1 YriuLourencoRodrigues_DISSERT.pdf: 2562345 bytes, checksum: 91fc4e0062ca0529e47b9cfb3eaa735a (MD5) Previous issue date: 2017-09-29 / Coordena??o de Aperfei?oamento de Pessoal de N?vel Superior (CAPES) / O presente estudo teve por objetivo investigar o comportamento biomec?nico de diferentes dimens?es de pr?teses temporomandibulares personalizadas, por meio do M?todo de Elementos Finitos. A partir de uma tomografia computadorizada, um modelo computacional 3D da mand?bula foi gerado. Este modelo foi replicado e suas c?pias submetidas a tr?s diferentes ressec??es progressivas, as quais foram reabilitadas com pr?teses temporomandibulares personalizadas, gerando assim tr?s modelos experimentais (Modelo Incisura Mandibular ? MIM, Modelo Linha Oclusal ? MLO e Modelo 3? Molar ? M3M) mais a mand?bula intacta (Modelo Controle ? MC). Com base nas geometrias geradas foram criados quatros modelos de elementos finitos, com prop?sito de mimetizar uma condi??o cl?nica. Os modelos foram considerados isotr?picos, homog?neos e linearmente el?sticos. Por meio de um software de simula??o computacional foram simuladas as a??es das principais for?as musculares que atuam sobre a mand?bula, e realizada uma an?lise da distribui??o de tens?es e deforma??o no osso adjacente ? pr?tese, c?ndilo oposto ? pr?tese, pr?tese personalizada e parafusos de fixa??o. Foi poss?vel observar que houve um aumento dos valores do equivalente de von Mises nos ossos adjacentes e nos c?ndilos opostos, ap?s a instala??o das pr?teses. Entretanto estes valores permaneceram semelhantes entre os modelos. As concentra??es de tens?es nos ossos adjacentes e nas pr?teses se apresentaram na regi?o em torno dos parafusos, e estes ?ltimos apresentaram os maiores picos de tens?o que variaram de 836 MPa a 13010 MPa. J? na an?lise da distribui??o de deforma??es foi poss?vel observar que n?o houve concentra??o de deforma??es nos c?ndilos opostos. Entretanto o MIM apresentou os maiores picos de deforma??o no osso adjacente e na pr?tese, enquanto que o M3M apresentou o maior nos parafusos, chegando a 9770 ??. O aumento das dimens?es das pr?teses personalizadas levou ao aumento dos picos de tens?o e deforma??o a valores cr?ticos nos ossos adjacentes ?s pr?teses e parafusos de fixa??o, que pode comprometer a estabilidade e fun??o das pr?teses, em todos os modelos experimentais. O aumento no n?mero de parafusos poder? conferir uma adequada estabilidade e distribui??o de tens?o para os modelos, sobretudo com o aumento das dimens?es das pr?teses temporomandibulares; necessitando assim de mais que tr?s parafusos de fixa??o. / The present study aimed to investigate the biomechanical influence of different dimensions of custom temporomandibular prostheses by means of the Finite Element Method. Frist, a 3D computational model of the mandible was generated using computerized tomography. This model was replicated and its copies were then submitted to three different progressive resections, which were rehabilitated with custom temporomandibular prostheses, thus generating three experimental models (Mandibular Notch Model ? MIM, Occlusal Line Model ? MLO and 3rd Molar Model ? M3M) plus the intact mandible (Control Model ? MC). Based on the generated geometries, four models of finite elements were created, aiming to mimic a clinical condition. The models were considered isotropic, homogeneous and linearly elastic. Using virtual simulation software, the actions of the main muscular forces acting on the mandible were reproduced, and analyses of the stress and strain distribution on the adjacent bones of the prosthesis, opposite condyle to the prosthesis, personalized prosthesis, and on fixation screws were performed. It was possible to observe that there was an increase in von Mises equivalent values in the adjacent bones and in the opposing condyles after installation of the prostheses. However, these values remained similar between the models. Stress concentrations in adjacent bones and prostheses occurred in the region around the screws, and the latter had the highest stress peaks ranging from 836 MPa to 13010 MPa. In the strain distribution analysis, it was possible to observe that there was no concentration of strain in the opposing condyles. However, the MIM showed the highest strain peaks in the adjacent bone and prosthesis, whereas the M3M presented the highest strain on the screws, reaching 9770 ??. Increasing the dimensions of the customized prostheses led to an increase of the stress peaks and strain at critical values in the bones adjacent to the prostheses and fixation screws which, can compromise the stability and function of the prostheses in all the experimental models. Increasing the number of screws could give adequate stability and stress distribution to the models, especially with the increase of the dimensions of the temporomandibular prosthesis, then requiring more than three fixing screws.

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