Examinando por Autor "Naranjo M"

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    Ítem
    Differences in the microstructure and fatigue properties of dentine between residents of North and South America.
    (PERGAMON-ELSEVIER SCIENCE LTD, 2014-10-01) Ivancik J; Naranjo M; Correa S; Ossa A; Tay FR; Pashley DH; Arola D; Universidad EAFIT. Departamento de Ingeniería Mecánica; Bioingeniería GIB (CES – EAFIT)
    UNLABELLED: Spatial variations in the microstructure of dentine contribute to its mechanical behaviour. OBJECTIVE: The objective of this investigation was to compare the microstructure and fatigue behaviour of dentine from donors of two different countries. METHODS: Caries-free third molars were obtained from dental practices in Colombia, South America and the US to assemble two age-matched samples. The microstructure of the coronal dentine was evaluated at three characteristic depths (i.e. deep, middle and superficial dentine) using scanning electron microscopy and image processing techniques. The mechanical behaviour of dentine in these three regions was evaluated by the fatigue crack growth resistance. Cyclic crack growth was achieved in-plane with the dentine tubules and the fatigue crack growth behaviour was characterized in terms of the stress intensity threshold and the Paris Law parameters. RESULTS: There was no difference in the tubule density between the dentine of patients from the two countries. However, there were significant differences (p
  • No hay miniatura disponible
    Ítem
    Differences in the microstructure and fatigue properties of dentine between residents of North and South America.
    (PERGAMON-ELSEVIER SCIENCE LTD, 2014-10-01) Ivancik J; Naranjo M; Correa S; Ossa A; Tay FR; Pashley DH; Arola D; Universidad EAFIT. Departamento de Ingeniería de Diseño; Ingeniería de Diseño (GRID)
    UNLABELLED: Spatial variations in the microstructure of dentine contribute to its mechanical behaviour. OBJECTIVE: The objective of this investigation was to compare the microstructure and fatigue behaviour of dentine from donors of two different countries. METHODS: Caries-free third molars were obtained from dental practices in Colombia, South America and the US to assemble two age-matched samples. The microstructure of the coronal dentine was evaluated at three characteristic depths (i.e. deep, middle and superficial dentine) using scanning electron microscopy and image processing techniques. The mechanical behaviour of dentine in these three regions was evaluated by the fatigue crack growth resistance. Cyclic crack growth was achieved in-plane with the dentine tubules and the fatigue crack growth behaviour was characterized in terms of the stress intensity threshold and the Paris Law parameters. RESULTS: There was no difference in the tubule density between the dentine of patients from the two countries. However, there were significant differences (p
  • No hay miniatura disponible
    Ítem
    Differences in the microstructure and fatigue properties of dentine between residents of North and South America.
    (PERGAMON-ELSEVIER SCIENCE LTD, 2014-10-01) Ivancik J; Naranjo M; Correa S; Ossa A; Tay FR; Pashley DH; Arola D; Ivancik J; Naranjo M; Correa S; Ossa A; Tay FR; Pashley DH; Arola D; Universidad EAFIT. Departamento de Ingeniería de Producción; Materiales de Ingeniería
    UNLABELLED: Spatial variations in the microstructure of dentine contribute to its mechanical behaviour. OBJECTIVE: The objective of this investigation was to compare the microstructure and fatigue behaviour of dentine from donors of two different countries. METHODS: Caries-free third molars were obtained from dental practices in Colombia, South America and the US to assemble two age-matched samples. The microstructure of the coronal dentine was evaluated at three characteristic depths (i.e. deep, middle and superficial dentine) using scanning electron microscopy and image processing techniques. The mechanical behaviour of dentine in these three regions was evaluated by the fatigue crack growth resistance. Cyclic crack growth was achieved in-plane with the dentine tubules and the fatigue crack growth behaviour was characterized in terms of the stress intensity threshold and the Paris Law parameters. RESULTS: There was no difference in the tubule density between the dentine of patients from the two countries. However, there were significant differences (p
  • No hay miniatura disponible
    Ítem
    Evaluation of the structural behavior of three and four implant-supported fixed prosthetic restorations by finite element analysis.
    (ELSEVIER IRELAND LTD, 2012-04-01) Correa S; Ivancik J; Isaza JF; Naranjo M; Universidad EAFIT. Departamento de Ingeniería Mecánica; Bioingeniería GIB (CES – EAFIT)
    PURPOSE: There is much controversy about the minimum number of implants and maximum cantilever length in mandible prosthetic restoration. Finite elements analysis of three and four implant-supported prostheses was performed to determine the stresses in the superstructure, implants and cortical bone and, therefore, the failure prediction for each restoration. METHODS: An edentulous mandible was modeled from CT scan images. Two finite element models of three and four implant-supported prostheses with cantilever lengths of 10 and 15 mm were created. Occlusal loads in different parts of the superstructure were applied and shear and normal stresses were calculated. RESULTS: Two failure criteria were analyzed: the von Mises criterion for isotropic materials (superstructure and implants) and the Tsai-Wu criterion for transversely isotropic material (cortical bone). Both criteria predict failure in the three implant-supported prosthesis for all cases analyzed. The same applies for the four-implant prosthesis of 15 mm cantilever length. However, four implants and a cantilever length of 10mm passed the failure criteria and were considered safe. CONCLUSIONS: The results from the patient analyzed showed that fixed support prostheses on three implants are not recommended from a structural point of view because they do not adequately support occlusal loads. Excessive stress in the superstructure and the cortical bone can be expected, which would anticipate the failure of the restoration. Fixed support prostheses on four implants with a cantilever length of 10mm properly resist occlusal loading.
  • No hay miniatura disponible
    Ítem
    Evaluation of the structural behavior of three and four implant-supported fixed prosthetic restorations by finite element analysis.
    (ELSEVIER IRELAND LTD, 2012-04-01) Correa S; Ivancik J; Isaza JF; Naranjo M; Universidad EAFIT. Departamento de Ingeniería de Diseño; Ingeniería de Diseño (GRID)
    PURPOSE: There is much controversy about the minimum number of implants and maximum cantilever length in mandible prosthetic restoration. Finite elements analysis of three and four implant-supported prostheses was performed to determine the stresses in the superstructure, implants and cortical bone and, therefore, the failure prediction for each restoration. METHODS: An edentulous mandible was modeled from CT scan images. Two finite element models of three and four implant-supported prostheses with cantilever lengths of 10 and 15 mm were created. Occlusal loads in different parts of the superstructure were applied and shear and normal stresses were calculated. RESULTS: Two failure criteria were analyzed: the von Mises criterion for isotropic materials (superstructure and implants) and the Tsai-Wu criterion for transversely isotropic material (cortical bone). Both criteria predict failure in the three implant-supported prosthesis for all cases analyzed. The same applies for the four-implant prosthesis of 15 mm cantilever length. However, four implants and a cantilever length of 10mm passed the failure criteria and were considered safe. CONCLUSIONS: The results from the patient analyzed showed that fixed support prostheses on three implants are not recommended from a structural point of view because they do not adequately support occlusal loads. Excessive stress in the superstructure and the cortical bone can be expected, which would anticipate the failure of the restoration. Fixed support prostheses on four implants with a cantilever length of 10mm properly resist occlusal loading.