No description available.

In this thesis a new framework is proposed for obtaining the spongy bone, cortical bone, muscle and adipose tissue from MRI data. The method focuses on the accurate extraction of the edges of the target tissues, which is the main drawback of previous works. In this framework six new methods, as listed in section 1.3, are utilized together for improving the result of the segmentation by detecting the relational position of the tissues, acquiring the best possible contribution from the operator in terms of time and efficiency, forward and backward transfer of the segmented tissues at the seed slice and using the newly proposed Deformable Kernel Fuzzy-C Mean (DKFCM) method for improving the result of segmentation on the edges. This method first limits the searching area for the voxels of the target tissue from the whole data to a small strip around the edges of the target tissue. Then, it applies a very accurate segmentation on the searching area, using a deformable kernel, which is capable of adapting itself with the shape of the edge. Comparing the results of this work with some popular MRI segmentation methods like active contour, watershed, FCM and also some heuristic methods, which are proposed in literature for segmenting the MRI to four tissues, demonstrates the superiority of the proposed method especially on the edges.

Técnicas para reconstruções ósseas são descritas em artigos científicos e dentre as barreiras mecânicas utilizadas, a malha de titânio vem demonstrando possibilidades de tratamento para ganho ósseo. Estudos pré-clínicos são escassos na literatura relatando a melhor morfologia de malha de titânio a ser utilizada, além da necessidade de uso de membrana oclusiva adicional. Dessa forma, o objetivo do estudo é avaliar se há diferença na qualidade e volume ósseo formado ao utilizar malhas de titânio com diferentes diâmetros de poro, e avaliar a necessidade de utilização de uma membrana adicional, sobre a malha de titânio. Para este estudo foram utilizados 28 ratos adultos machos do tipo Wistar, com peso médio de 410,8 gramas. Os animais foram divididos aleatoriamente em quatro grupos experimentais principais: Grupo P300: uso de malhas de titânio Painel Grade 15 Neodent®, com espessura de 0,3 mm e perfuração medindo 3 mm entre os vértices (n = 7); Grupo P175: uso de malhas de titânio Painel Grade 20 Neodent®, com espessura de 0,3 mm e perfuração com 1,75 mm diâmetro (n = 7); Grupo P85: uso de malhas de titânio Bionnovation® Surgitime Titânio, com espessura de 0,04 mm e perfuração com 0,85 mm de diâmetro (n = 7); Grupo P15: uso de malhas de titânio Bionnovation® Surgitime Titânio de espessura de 0,04 mm e perfuração com 0,15 mm de diâmetro (n = 7). Em todos os grupos, cada fêmur foi subdividido em teste (fêmur em que foi utilizado Bio-Oss Collagen® e membrana de colágeno BioGide®) e controle (apenas Bio-Oss Collagen®). Após 24 horas do procedimento cirúrgico, o qual foi realizado com anestesia geral, os animais foram submetidos a análise de microtomografia computadorizada in vivo, também sob anestesia. Após 30 dias, foram novamente submetidos a microtomografia computadorizada in vivo e, em seguida, eutanasiados para processamento histológico. Após análise estatística, foi observado que não houveram diferenças estatísticas em relação aos parâmetros volumétricos, nas comparações intra e entre grupos. Em relação a densidade mineral óssea, nas comparações intra grupos, relacionando fêmur teste e controle, não foram observadas significâncias estatísticas. Nas comparações entre grupos, foram observadas maior densidade nos grupos com maior diâmetro de perfuração (p<0,05). Nas análises histológicas, foi possível observar neoformação óssea do tipo esponjosa, demonstrando o mesmo padrão em todos os grupos, com presença de osteócitos em lacuna, início de um processo de amadurecimento ósseo com formação de lamelas concêntricas e íntima relação do novo osso formado pelo enxerto e o fêmur. De acordo com os resultados pode-se concluir que, o diâmetro do poro da malha de diâmetro pode interferir na qualidade óssea, porém, irá depender do enxerto ósseo utilizado, e o uso adicional de membrana de colágeno, quando associada a enxerto ósseo, não determinou a formação de novo osso de qualidade superior / Techniques for bone reconstruction are described in scientific articles and, among mechanical barriers used, titanium mesh has been showing possibilities of treatment for bone gain. Preclinical studies are scarce in the literature reporting the best morphology of titanium mesh to be used, in addition to the need for additional occlusive membrane. Thus, the objective of this study is to evaluate if there is a difference in bone quality and volume formed when using titanium meshes with different pore diameters, and to evaluate the need to use an additional membrane on the titanium mesh. For this study, 28 male Wistar male rats with an average weight of 410.8 grams were used. The animals were randomly divided into four main experimental groups: Group P300: use of titanium meshes Grid Panel 15 Neodent®, with thickness of 0.3 mm and perforation measuring 3 mm between vertices (n = 7); Group P175: use of titanium meshes Grid Panel 20 Neodent®, with thickness of 0.3 mm and perforation with 1.75 mm diameter (n = 7); Group P85: use of titanium meshes Bionnovation® Surgitime Titanium, 0.04 mm thick and 0.85 mm diameter (n = 7); Group P15: use of titanium meshes Bionnovation® Surgitime Titanium thickness 0.04 mm and perforation with 0.15 mm diameter (n = 7). In all groups, each femur was subdivided into test (femur in which Bio-Oss Collagen® and BioGide® collagen membrane was used) and control (Bio-Oss Collagen® only). After 24 hours of the surgical procedure, which was performed under general anesthesia, the animals were submitted to in vivo microtomography, also under anesthesia. After 30 days, they were again submitted to computerized in vivo microtomography and then euthanized for histological processing. After statistical analysis, it was observed that there were no statistical differences in relation to the volumetric parameters, in intra and inter group comparisons. Regarding bone mineral density, in intragroup comparisons, relating femur test and control, no statistical significance was observed. In the comparisons between groups, higher densities were observed in the groups with greater drilling diameter (p <0.05). In the histological analyzes, it was possible to observe new bone formation of the spongy type, showing the same pattern in all groups, with presence of osteocytes in the gap, beginning of a bone ripening process with concentric lamella formation and an intimate relation of the new bone formed by the graft and the femur. According to the results, it can be concluded that the pore diameter of the diameter mesh may interfere with bone quality, however, it will depend on the bone graft used, and the additional use of collagen membrane, when associated with a bone graft, does not determined the formation of new bone of superior quality

This diploma thesis is oriented on a stress – strain analysis of the jaw bone with a screw dental implant. There is a literature search on this theme in the beginning of this work. Solutions deformation and stress the system lower jaw and implant was performed computational modeling, by using the finite element method. Modeling is part of the lower jaw with dental implants applied screw type Ankylos, Bränemark and implant with metric thread. The thesis is described in detail development of calculation model system and solutions. To create a geometry model of geometry Solidworks 2007 was used. To create calculation model and the solution was implamented in the computer systém ANSYS 11.0 and ANSYS Workbench.