Examinando por Materia "skull"

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    The global impact of sutures assessed in a finite element model of a macaque cranium
    (WILEY-LISS, 2010-09-01) Wang, Qian; Smith, Amanda L.; Strait, David S.; Wright, Barth W.; Richmond, Brian G.; Grosse, Ian R.; Byron, Craig D.; Zapata, Uriel; Universidad EAFIT. Departamento de Ingeniería Mecánica; Bioingeniería GIB (CES – EAFIT)
    The biomechanical significance of cranial sutures in primates is an open question because their global impact is unclear, and their material properties are difficult to measure. In this study, eight suture-bone functional units representing eight facial sutures were created in a finite element model of a monkey cranium. All the sutures were assumed to have identical isotropic linear elastic material behavior that varied in different modeling experiments, representing either fused or unfused sutures. The values of elastic moduli employed in these trials ranged over several orders of magnitude. Each model was evaluated under incisor, premolar, and molar biting conditions. Results demonstrate that skulls with unfused sutures permitted more deformations and experienced higher total strain energy. However, strain patterns remained relatively unaffected away from the suture sites, and bite reaction force was likewise barely affected. These findings suggest that suture elasticity does not substantially alter load paths through the macaque skull or its underlying rigid body kinematics. An implication is that, for the purposes of finite element analysis, omitting or fusing sutures is a reasonable modeling approximation for skulls with small suture volume fraction if the research objective is to observe general patterns of craniofacial biomechanics under static loading conditions. The manner in which suture morphology and ossification affect the mechanical integrity of skulls and their ontogeny and evolution awaits further investigation, and their viscoelastic properties call for dynamic simulations. © 2010 Wiley-Liss, Inc.
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    Material properties of the skull layers of the primate parietal bone: A single-subject study
    (Public Library of Science, 2020-01-01) Zapata, U.; Wang, Q.; Universidad EAFIT. Departamento de Ingeniería Mecánica; Bioingeniería GIB (CES – EAFIT)
    The outer cortical table of the parietal bone has been commonly used as a calvarial bone graft site for the craniofacial reconstruction. However, little is known about how removing the outer table may affect the function and structure of the inner table, and how the knowledge of the biomechanics and material properties of cortical bones will help the calvarial graft to better integrate into the biological and mechanical functions of its surrounding native tissues. In this study, it was hypothesized that there were significant differences in both density and material properties between inner and outer cortical plates in cranial bones. Twelve cylindrical specimens, including inner-outer layers, of cortical parietal bone of a female baboon were collected. Cortical thicknesses and densities were measured, and elastic properties were assessed using an ultrasonic technique. Results demonstrated remarkable difference in both thickness (t = 8.248, p .0.05) and density (t = 4.926, p.0.05) between inner and outer cortical paired samples. Orthotropic characteristics of the cortical plates were detected as well, these findings suggest that there are differences in biomechanical properties between two surfaces of cranial bones at both tissue and organ levels. How these differences are linked to the stress environments of the inner and outer cranial cortical layers awaits further studies. Further study will greatly enhance our ability to address questions derived from both morphological and craniofacial medicine fields about the development and biomechanics of craniofacial skeletons. © 2020 Zapata, Wang.
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    Ítem
    Material properties of the skull layers of the primate parietal bone: A single-subject study
    (Public Library of Science, 2020-01-01) Zapata, U.; Wang, Q.; Zapata, U.; Wang, Q.; Universidad EAFIT. Departamento de Ingeniería de Producción; Materiales de Ingeniería
    The outer cortical table of the parietal bone has been commonly used as a calvarial bone graft site for the craniofacial reconstruction. However, little is known about how removing the outer table may affect the function and structure of the inner table, and how the knowledge of the biomechanics and material properties of cortical bones will help the calvarial graft to better integrate into the biological and mechanical functions of its surrounding native tissues. In this study, it was hypothesized that there were significant differences in both density and material properties between inner and outer cortical plates in cranial bones. Twelve cylindrical specimens, including inner-outer layers, of cortical parietal bone of a female baboon were collected. Cortical thicknesses and densities were measured, and elastic properties were assessed using an ultrasonic technique. Results demonstrated remarkable difference in both thickness (t = 8.248, p .0.05) and density (t = 4.926, p.0.05) between inner and outer cortical paired samples. Orthotropic characteristics of the cortical plates were detected as well, these findings suggest that there are differences in biomechanical properties between two surfaces of cranial bones at both tissue and organ levels. How these differences are linked to the stress environments of the inner and outer cranial cortical layers awaits further studies. Further study will greatly enhance our ability to address questions derived from both morphological and craniofacial medicine fields about the development and biomechanics of craniofacial skeletons. © 2020 Zapata, Wang.