Thesis (Ph. D.)--University of Queensland, 2006. / Includes bibliographical references.

Orientador: Paulo Henrique Ferreira Caria / Tese (doutorado) - Universidade Estadual de Campinas. Faculdade de Odontologia de Piracicaba / Made available in DSpace on 2018-08-16T05:17:07Z (GMT). No. of bitstreams: 1 Prado_FelippeBevilacqua_D.pdf: 2295731 bytes, checksum: b3c79f4fe2cee1adf3eca0dd86f0eed4 (MD5) Previous issue date: 2010 / Resumo: Introdução: As tensões mastigatórias são absorvidas pelos processos alveolares e são dissipadas do pilar zigomático para o restante do crânio. A análise por elementos finitos é útil para avaliar a dissipação da tensão e simular o comportamento mecânico de estruturas biológicas. Objetivo: O Objetivo deste estudo foi analisar a dissipação da tensão principal máxima na região do Pilar Zigomático de um crânio humano, ao simular a oclusão dos molares. Material e Método: Um modelo dos ossos faciais foi construído a partir de imagens tomograficas computadorizadas com 0,25 mm de espessura de um crânio humano dentado pertencente ao Departamento de Morfologia da FOP - UNICAMP. O modelo geométrico foi construído com base na modelagem por meio do software Rhinoceros 4,0 (modelagem tridimensional por superfícies NURBS), utilizando a técnica de BioCAD e software MSC / Nastran ® 4.5 para Windows (The Corporation MacNeal-Schwendler, Savannah, GA, E.U.A.) que reproduziu o modelo de elementos finitos com as propriedades mecânicas da estrutura original. Resultados: Durante a aplicação da carga nos molares superiores, surgiram na superfície interna do seio maxilar duas linhas tensão máxima principal a partir do assoalho do seio maxilar, a primeira em direção ao pilar zigomático e a segunda para a região póstero-lateral do seio maxilar. Na região de transição entre a maxila e a crista zigomático maxilar foi observado uma área de tensão máxima principal nula. Conclusão: A tensão máxima principal durante a oclusão molar não é transferida diretamente ao pilar zigomático, mas sim para estruturas adjacentes. / Abstract: Introduction: Masticatory stress are absorbed by the alveolar processes and dissipated from the Zygomatic Pillar for the hole skull. The finite element analysis is useful to evaluate the stress dissipation and simulate the mechanical behavior of biological structures. Objective: The objective of this study was to analyze the dissipation of maximum principal strain in the region of the Pillar Zygomatic of a human skull during molars occlusion. Material and Methods: A model of the facial bones was constructed from computed tomography images with 0.25 mm thickness of a dentate human skull from the Department of Morphology, FOP - UNICAMP. The geometric model was built based on modeling using the Rhinoceros 4.0 software (three-dimensional modeling by NURBS surfaces), using the technique of BioCAD and MSC / Nastran for Windows ® 4.5 software (The MacNeal-Schwendler Corporation, Savannah, GA USA) which reproduced the finite element model with the mechanical properties of the original structure. Results: During application of the load on the upper molars two lines of maximum principal strain appeared on the inner surface of the maxillary sinus from the maxillary sinus floor, the first toward the Zygomatic Pillar and the second to the posterior of the maxillary sinus. Conclusion: The maximum principal strain during molar occlusion is not transferred directly to the Zygomatic Pillar, but to adjacent structures. / Doutorado / Anatomia / Doutor em Biologia Buco-Dental

Orientador: Paulo Henrique Ferreira Caria / Dissertação (mestrado) - Universidade Estadual de Campinas, Faculdade de Odontologia de Piracicaba / Made available in DSpace on 2018-08-17T15:52:01Z (GMT). No. of bitstreams: 1 Freire_AlexandreRodrigues_M.pdf: 1572266 bytes, checksum: 71737a1b0efda969642a5281beaa6ff4 (MD5) Previous issue date: 2011 / Resumo: O tecido ósseo do crânio humano é organizado para estabelecer adaptação à função mecânica. Os ossos que compõem o esqueleto facial formam os pilares de sustentação das forças mastigatórias, sendo que o pilar na região anterior é denominado pilar canino. Teoricamente as tensões mecânicas nesta região se originam no dente canino superior e se dissipam em direção à glabela. O objetivo deste estudo foi avaliar os locais de dissipação e a intensidade das tensões mecânicas no dente canino superior e pilar canino por meio da análise de elementos finitos tridimensional. A partir de cortes tomográficos de 0,25 mm de espessura de um crânio humano, masculino e de aproximadamente 38 anos, foi construído um modelo de elementos finitos formado por 135072 nós e 84157 elementos pelo software Ansys v12. Sobre a margem inferior do osso e arco zigomáticos foi aplicada uma força mastigatória de 200N, simulando a ação do músculo masseter e o suporte foi aplicado no contato oclusal do dente canino superior. Foram analisadas as tensões de Von-mises e máxima principal. As tensões de Vonmises determinaram a dissipação pelo pilar canino, com áreas concentradas na eminência canina e no processo frontal da maxila. A tensão máxima principal mostrou as áreas de compressão no corpo da maxila, processo frontal da maxila, próximo à sutura frontomaxilar e no osso nasal e, tração no processo alveolar e base do processo frontal da maxila. Conclui-se que as tensões se dissipam pelo pilar canino conforme os fundamentos teóricos da biomecânica, de maneira não uniforme com concentração de tensões de tração e compressão em diferentes áreas. / Abstract: The bone tissue of the human skull is organized to provide adaptation to mechanical function. The bones of the facial skeleton form the pillars of support of the masticatory forces, and in the anterior region is called canine pillar. Theoretically, the mechanical stresses in this region originate in the upper canine tooth and dissipate toward the glabella. The aim of this study was to evaluate the sites of dissipation and the intensity of mechanical stresses in the upper canine and canine pillar by tridimensional finite element analysis. From CT images with 0.25 mm thickness of a male human skull, with approximately 38 years, was generated a finite element model, which consists of 13,5072 nodes and 84,157 elements, through of the software Ansys v12. On the inferior margin of the zygomatic bone and zigomatic arch was applied a masticatory force of 200N, simulating the action of the masseter muscle, and a support was applied in the occlusal contact of the upper canine tooth. Were analyzed the Von-mises and maximum principal stresses. The Von-mises stresses determined the stress dissipation in the canine pillar, with areas concentrated at the canine eminence and frontal process of maxilla. The maximum principal stress showed compression areas at the body of the maxilla, frontal process, close to the frontomaxillary suture and in the nasal bone. Tensile stress located on the alveolar process and the base of the frontal process. In conclusion, the stresses were dissipated by the canine pillar as the theoretical principles of biomechanics, not uniformly and with concentration of tensile stress and compression in different areas. / Mestrado / Anatomia / Mestre em Biologia Buco-Dental

Objectives<p>The geometric configuration of skull is complex and unique to each individual. The main objectives of this study are two fold: 1) to provide a new technique to define the outline of skull profile and 2) to find the common factors defining the ultimate skull configuration in adult population. The secondary objective was to explore the effect of age and sex on skull shape formation.<p>Materials & Methods <p>Ninety-three lateral skull x-ray from the CT scan films were selected and digitized. The lateral skull surface was divided into 3 regions based on the presumed location of coronal and lambdoid sutures. A software program (Canvas 7) was used to match the outer surface of lateral skull with circular curves. Three main curvatures (frontal, parietal, occipital) were consistently identified to overlap the skull periphery. The radius, cord length and inclination of each curvature were measured.. Factor analysis technique was also used to reduce the number of variables explaining the overall shape of skull. Student t-test and regression analysis was also used to explore the effect of sex and age on skull shape. <p>Results <p>There were total of 93 patients in this study (54% male). The average values for three defined curvatures of the skull profile were recorded. Factor analysis produced 3 factors. The first factor explained 32% of total variance and was related to the overall size of the head as represented by total length and the radius of the curvature in vertex and back of the head. The second factor covered 26% of the variance representing the inverse correlation between the angle of the frontal and parietal curves. The third factor revealed the direct correlation of occipital and parietal angle. In all of these factors, the frontal zone variation was independent or opposite of the parieto-occipital zone. A strong direct association between the total length of skull, occipital curve radius and length with the sex was shown. No age related variable was identified.<p>Conclusions <p>There is a large variation in the values of different part of the skull. The skull profile topography can be defined mathematically by two distinct territories: frontal and parieto-occipital zones. These territories hinge on the coronal suture. Therefore, coronal suture may play a dominant role in final skull configuration.

Objectives<p>The geometric configuration of skull is complex and unique to each individual. The main objectives of this study are two fold: 1) to provide a new technique to define the outline of skull profile and 2) to find the common factors defining the ultimate skull configuration in adult population. The secondary objective was to explore the effect of age and sex on skull shape formation.<p>Materials & Methods <p>Ninety-three lateral skull x-ray from the CT scan films were selected and digitized. The lateral skull surface was divided into 3 regions based on the presumed location of coronal and lambdoid sutures. A software program (Canvas 7) was used to match the outer surface of lateral skull with circular curves. Three main curvatures (frontal, parietal, occipital) were consistently identified to overlap the skull periphery. The radius, cord length and inclination of each curvature were measured.. Factor analysis technique was also used to reduce the number of variables explaining the overall shape of skull. Student t-test and regression analysis was also used to explore the effect of sex and age on skull shape. <p>Results <p>There were total of 93 patients in this study (54% male). The average values for three defined curvatures of the skull profile were recorded. Factor analysis produced 3 factors. The first factor explained 32% of total variance and was related to the overall size of the head as represented by total length and the radius of the curvature in vertex and back of the head. The second factor covered 26% of the variance representing the inverse correlation between the angle of the frontal and parietal curves. The third factor revealed the direct correlation of occipital and parietal angle. In all of these factors, the frontal zone variation was independent or opposite of the parieto-occipital zone. A strong direct association between the total length of skull, occipital curve radius and length with the sex was shown. No age related variable was identified.<p>Conclusions <p>There is a large variation in the values of different part of the skull. The skull profile topography can be defined mathematically by two distinct territories: frontal and parieto-occipital zones. These territories hinge on the coronal suture. Therefore, coronal suture may play a dominant role in final skull configuration.

Thesis (Ph. D.)--University of Hong Kong, 2008. / Includes bibliographical references (leaf 153-171) Also available in print.

Thesis (M.S.)--University of Michigan, 1968.

Thesis (M.S.)--University of Minnesota, 1999. / eContent provider-neutral record in process. Description based on print version record. Includes bibliographical references.

Thesis (doctoral)--Friedrich Wilhelms-Universität zu Bonn, 1950. / Includes bibliographical references (p. 59-62).

Thesis (M.S.)--University of Michigan, 1968.