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Ítem Biomechanical characteristics of regenerated cortical bone in the canine mandible(WILEY-BLACKWELL, 2011-07-01) Zapata, Uriel; Opperman, Lynne A.; Kontogiorgos, Elias; Elsalanty, Mohammed E.; Dechow, Paul C.; Universidad EAFIT. Departamento de Ingeniería Mecánica; Bioingeniería GIB (CES – EAFIT)To test the mechanical properties of regenerate cortical bone created using mandibular bone transport (MBT) distraction, five adult male American foxhound dogs underwent unilateral distraction of the mandible with a novel MBT device placed to linearly repair a 30-35 mm bone defect. The animals were sacrificed 12 weeks after the beginning of the consolidation period. Fourteen cylindrical specimens were taken from the inner (lingual) and outer (buccal) plates of the reconstructed mandible and 21 control specimens were removed from the contralateral aspect of the mandible. The mechanical properties of the 35 cylindrical cortical bone specimens were assessed by using a non-destructive pulse ultrasound technique. Results showed that all of the cortical mechanical properties exhibit higher numerical values on the control side than the MBT regenerate side. In addition, both densities and the elastic moduli in the direction of maximum stiffness of the regenerate cortical bone specimens are higher on the lingual side than the buccal side. Interestingly, there is no statistical difference between elastic modulus (E1 and E2) in orthogonal directions throughout the 35 cortical specimens. The data suggest that not only is the regenerate canine cortical bone heterogeneous, but the elastic mechanical properties tend to approximate transverse isotropy at a tissue level, as opposed to control cortical bone, which is orthotropic. In addition, the elastic mechanical properties are higher not only on the control side but also in the lingual anatomical position, suggesting a stress shielding effect from the presence of the reconstruction plate. © 2011 John Wiley & Sons, Ltd.Ítem Biomechanics of the canine mandible during bone transport distraction osteogenesis(ASME, 2014-11-01) Zapata, Uriel; Dechow, Paul C.; Watanabe, Ikuya; Elsalanty, Mohammed E.; Opperman, Lynne A.; Universidad EAFIT. Departamento de Ingeniería Mecánica; Bioingeniería GIB (CES – EAFIT)This study compared biomechanical patterns between finite element models (FEMs) and a fresh dog mandible tested under molar and incisal physiological loads in order to clarify the effect of the bone transport distraction osteogenesis (BTDO) surgical process. Three FEMs of dog mandibles were built in order to evaluate the effects of BTDO. The first model evaluated the mandibular response under two physiological loads resembling bite processes. In the second model, a 5.0 cm bone defect was bridged with a bone transport reconstruction plate (BTRP). In the third model, new regenerated bony tissue was incorporated within the defect to mimic the surgical process without the presence of the device. Complementarily, a mandible of a male American foxhound dog was mechanically tested in the laboratory both in the presence and absence of a BTRP, and mechanical responses were measured by attaching rosettes to the bone surface of the mandible to validate the FEM predictions. The relationship between real and predicted values indicates that the stress patterns calculated using FEM are a valid predictor of the biomechanics of the BTDO procedures. The present study provides an interesting correlation between the stiffness of the device and the biomechanical response of the mandible affected for bone transport. Copyright © 2014 by ASME.Ítem Biomechanics of the canine mandible during bone transport distraction osteogenesis(ASME, 2014-11-01) Zapata, Uriel; Dechow, Paul C.; Watanabe, Ikuya; Elsalanty, Mohammed E.; Opperman, Lynne A.; Zapata, Uriel; Dechow, Paul C.; Watanabe, Ikuya; Elsalanty, Mohammed E.; Opperman, Lynne A.; Universidad EAFIT. Departamento de Ingeniería de Producción; Materiales de IngenieríaThis study compared biomechanical patterns between finite element models (FEMs) and a fresh dog mandible tested under molar and incisal physiological loads in order to clarify the effect of the bone transport distraction osteogenesis (BTDO) surgical process. Three FEMs of dog mandibles were built in order to evaluate the effects of BTDO. The first model evaluated the mandibular response under two physiological loads resembling bite processes. In the second model, a 5.0 cm bone defect was bridged with a bone transport reconstruction plate (BTRP). In the third model, new regenerated bony tissue was incorporated within the defect to mimic the surgical process without the presence of the device. Complementarily, a mandible of a male American foxhound dog was mechanically tested in the laboratory both in the presence and absence of a BTRP, and mechanical responses were measured by attaching rosettes to the bone surface of the mandible to validate the FEM predictions. The relationship between real and predicted values indicates that the stress patterns calculated using FEM are a valid predictor of the biomechanics of the BTDO procedures. The present study provides an interesting correlation between the stiffness of the device and the biomechanical response of the mandible affected for bone transport. Copyright © 2014 by ASME.Ítem Creation of a three-dimensional model of the mandible and the TMJ in vivo by means of the finite element method.(Quintessenz Verlags GmbH, 2002-04-01) Castaño MC; Zapata U; Pedroza A; Jaramillo JD; Roldán S; Universidad EAFIT. Departamento de Ingeniería Mecánica; Bioingeniería GIB (CES – EAFIT)The aim of this study was to develop a three-dimensional finite element model of the mandible, including its TMJ. The model consisted of 7942 nodes and 41,010 elements, which were obtained from a convergence test, done to minimize the result error. It included cancellous and cortical bone, periodontal ligament, masticatory muscles (masseters, temporalis, lateral and internal pterygoids), teeth and the articular disk. All characteristics such as dental, mandibular, and muscle geometry were obtained from a computerized tomography (CT) of a living person. CT sections were scanned and digitized with a CAD software program. After images were adequately assembled, a vertical tracing was done which allowed the definition of a three-dimensional mesh. Modeling of teeth was carried out independently and the periodontal ligament was later included, limiting the alveolar area. Muscles were modeled based on flat-scale photographs and total muscle force was distributed in multiple vectors. The articular disk was generated having 2 mm of thickness with the combination of spring-type (axial stiffness) and gap-type (contact) elements. The model was then analyzed with finite element method (FEM) software where a mesh was generated and values for Poisson's ratio, elasticity, and shear modulus were assigned. These were orthotropic for cancellous and cortical bone, and isotropic for dentin, periodontal ligament, articular disk, and temporal bone. The boundary conditions were defined restricting the nodes on the periphery of the temporal bone. It was therefore possible to generate a three-dimensional finite element model based on information obtained in vivo.Ítem Deformation behaviour of aged coronal dentin(Blackwell Munksgaard, 2018-06-01) Montoya; C.; Arola; D.; Ossa; E.A.; Universidad EAFIT. Departamento de Ingeniería de Producción; Materiales de IngenieríaObjective: This study aimed to identify the changes in the time-dependent deformation response of coronal dentin with ageing and its relationship with changes in chemical composition. Background: The structural behaviour of dentin with ageing is affected by changes in the density and diameter of its dentinal tubules (ie porosity), as well as changes in chemical composition throughout the tooth. However, little is known about the time-dependent deformation behaviour of aged dentin and the importance of its hierarchical structure and variations in chemical composition. Materials and methods: The spherical indentation response of aged coronal dentin was analysed in the outer, middle and inner regions, and its time-dependent deformation response was modelled in terms of its microstructure and chemical composition using a model recently proposed for young dentin. Results: The viscous deformation behaviour of aged dentin followed a power-law response with a decrease in the stress exponent when compared to young dentin. These results can be explained by cross-linking of the collagen present in the tissue. Conclusion: A decrease in the deformation ability of aged dentin was found. This behaviour could be a result of a dissolution process and reprecipitation of the minerals present in intertubular dentin into the dentinal tubules. © 2018 John Wiley & Sons A/S and The Gerodontology Association. Published by John Wiley & Sons LtdÍtem Deterministic SIR (Susceptible-Infected-Removed) models applied to varicella outbreaks.(CAMBRIDGE UNIV PRESS, 2008-05-01) Giraldo JO; Palacio DH; Giraldo JO; Palacio DH; Universidad EAFIT. Departamento de Ciencias; Lógica y ComputaciónDeterministic SIR models were applied to simulate Susceptible-Infected-Removed and to estimate the threshold condition for varicella outbreaks in children, reported in Medellin, Colombia. The expected numbers of susceptible, infected and removed individuals were compared with observed cases from notification of varicella outbreaks to the local Board of Health and from survey data. The threshold condition was estimated by the basic reproductive ratio and by the relative removal rate, through which measures for preventing and curtailing the outbreaks were identified. The model demonstrated a reasonable fit to the observations, except in two of the six outbreaks which probably reflected under-registration of cases. In order to have prevented these outbreaks, between 4.4% and 52.9% of the susceptible population should have been vaccinated assuming an 85% vaccine effectiveness. Similarly, isolation of affected children should have been increased to between 4.3% and 44.8% per week.Ítem 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.Ítem Indentation damage and crack repair in human enamel.(ELSEVIER SCIENCE BV, 2013-05-01) Rivera C; Arola D; Ossa A; Rivera C; Arola D; Ossa A; Universidad EAFIT. Departamento de Ingeniería de Producción; Materiales de IngenieríaTooth enamel is the hardest and most highly mineralized tissue in the human body. While there have been a number of studies aimed at understanding the hardness and crack growth resistance behavior of this tissue, no study has evaluated if cracks in this tissue undergo repair. In this investigation the crack repair characteristics of young human enamel were evaluated as a function of patient gender and as a function of the distance from the Dentin Enamel Junction (DEJ). Cracks were introduced via microindentation along the prism direction and evaluated as a function of time after the indentation. Microscopic observations indicated that the repair of cracks began immediately after crack initiation and reaches saturation after approximately 48 h. During this process he crack length decreased up to 10% of the initial length, and the largest degree of reduction occurred in the deep enamel, nearest the DEJ. In addition, it was found that the degree of repair was significantly greater in the enamel of female patients.Ítem Material properties of mandibular cortical bone in the American alligator, Alligator mississippiensis(ELSEVIER SCIENCE INC, 2010-03-01) Zapata, Uriel; Metzger, Keith; Wang, Qian; Elsey, Ruth M.; Ross, Callum F.; Dechow, Paul C.; Universidad EAFIT. Departamento de Ingeniería Mecánica; Bioingeniería GIB (CES – EAFIT)This study reports the elastic material properties of cortical bone in the mandible of juvenile Alligator mississippiensis obtained by using an ultrasonic wave technique. The elastic modulus, the shear modulus, and Poisson's ratio were measured on 42 cylindrical Alligator bone specimens obtained from the lingual and facial surfaces of 4 fresh Alligator mandibles. The data suggest that the elastic properties of alligator mandibular cortical bone are similar to those found in mammals and are orthotropic. The properties most resemble those found in the cortex of mammalian postcranial long bones where the bone is most stiff in one direction and much less stiff in the two remaining orthogonal directions. This is different from cortical bone found in the mandibles of humans and some monkeys, where the bone has greatest stiffness in one direction, much less stiffness in another direction, and an intermediate amount in the third orthogonal direction. This difference suggests a relationship between levels of orthotropy and bending stress. The comparability of these elastic moduli to those of other vertebrates suggest that the high bone strain magnitudes recorded from the alligator mandible in vivo are not attributable to a lower stiffness of alligator mandibular bone. © 2009 Elsevier Inc.Ítem Personality and anxiety are related to health-related quality of life in unruptured intracranial aneurysm patients selected for non-intervention: A cross sectional study(Public Library of Science, 2020-03-12) Lemos, M.; Roman, J.Background Personality traits and mental health problems have been previously reported in unruptured intracranial aneurysm (UIA) patients; however, few studies have clarified the relations between these variables and health-related quality of life (HRQoL). This study was designed to characterize the personality traits, HRQoL and mental health of patients with UIA and to evaluate whether personality has an influence on HRQoL and whether this is mediated by the patients’ emotional symptoms. Methods Sixty-three patients with UIAs (mean age 62.6 years, 83.9% women) answered questionnaires for depression, anxiety, HRQoL and personality traits between June 2016 and May 2019. Results Eight percent of the sample had depression, and 27.4% had anxiety. Participants showed high levels of responsibility, kindness and neuroticism and low levels of extraversion and openness. HRQoL scores were normal compared with the Colombian population. Structural equation analysis showed that patients’ HRQoL was negatively affected by anxiety levels and that the latter are associated with the patient’s personality, where neuroticism is directly associated with symptomatology and inversely associated with extraversion. Conclusions The results of this study showed the importance of personality and emotional symptoms in the HRQoL of UIA patients. These results are important for developing strategies for psychological counseling in patients with UIAs. © 2020 Lemos et al. This is an open access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.Ítem Personality and anxiety are related to health-related quality of life in unruptured intracranial aneurysm patients selected for non-intervention: A cross sectional study(Public Library of Science, 2020-03-12) Lemos, M.; Roman, J.; Lemos, M.; Roman, J.; Universidad EAFIT. Departamento de Humanidades; Estudios en PsicologíaBackground Personality traits and mental health problems have been previously reported in unruptured intracranial aneurysm (UIA) patients; however, few studies have clarified the relations between these variables and health-related quality of life (HRQoL). This study was designed to characterize the personality traits, HRQoL and mental health of patients with UIA and to evaluate whether personality has an influence on HRQoL and whether this is mediated by the patients’ emotional symptoms. Methods Sixty-three patients with UIAs (mean age 62.6 years, 83.9% women) answered questionnaires for depression, anxiety, HRQoL and personality traits between June 2016 and May 2019. Results Eight percent of the sample had depression, and 27.4% had anxiety. Participants showed high levels of responsibility, kindness and neuroticism and low levels of extraversion and openness. HRQoL scores were normal compared with the Colombian population. Structural equation analysis showed that patients’ HRQoL was negatively affected by anxiety levels and that the latter are associated with the patient’s personality, where neuroticism is directly associated with symptomatology and inversely associated with extraversion. Conclusions The results of this study showed the importance of personality and emotional symptoms in the HRQoL of UIA patients. These results are important for developing strategies for psychological counseling in patients with UIAs. © 2020 Lemos et al. This is an open access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.Ítem A possible restriction of ferro- and ferricyanide oxidoreductase activities of rat liver mitochondria by the outer membrane.(ELSEVIER SCIENCE INC, 2005-11-15) Ramirez, LAG; Lemeshko, VV; Universidad EAFIT. Departamento de Ciencias; Ciencias Biológicas y Bioprocesos (CIBIOP)In this work, various ferro-ferricyanide oxidoreductase activities of rat liver mitochondria were studied to find conditions under which the outer membrane might restrict the flux of these highly charged non-biological anions. When the isotonic low ionic strength medium was supplemented with 25mM KCl, a several-fold increase in the succinate-ferricyanide reductase activity of mitochondria and in the rate of external NADH oxidation in the presence of ferrocyanide was observed. Mitochondrial respiration with 5mM ferrocyanide was almost completely inhibited after consumption of 3.8-18.5% of the dissolved oxygen, depending on the medium and the presence of 2,4-dinitrophenol. These and other experimental data together with mathematical modeling of the redox-state equilibrium suggest that the measured activities might be restricted by two factors: first, the permeability of the outer mitochondrial membrane and second, a strong influence of the ionic strength of incubation media on the intermembrane space redox reactions.Ítem Reliability of maximum bite force measurements in age-varying populations(WILEY-BLACKWELL PUBLISHING, INC, 2009-11-01) RoldÁn, S.; Buschang, P.H.; Isaza Saldarriaga, J.F.; Throckmorton, G.; Universidad EAFIT. Departamento de Ingeniería de Diseño; Ingeniería de Diseño (GRID)Summary In order for bite forces to be used clinically, they must be reliable. While bite force transducers are accurate and precise during bench tests, widely varying reliabilities of intra-oral bite forces have been reported when measured in human subjects. Because few studies have reported total reliability, the clinical use of intra-oral bite forces measurements remains questionable. The purposes of this study were to (i) estimate total reliability, including both within- and between-session reliabilities, of repeated maximum incisor and molar bite force measurements and (ii) demonstrate how extraneous variation affects reliability by comparing estimates for which the effects of age have and have not been controlled. A sample of 28 healthy subjects with Class I normal occlusion (seven subjects in each of four age groups: 5, 8, 11 and 14 years) performed two sessions approximately 90 min apart. Each session consisted of three maximum voluntary bites at three bite positions (incisor and right and left molars). For each bite position, between-subject variance (true variance), between-session variance and within-session variance were calculated using Multilevel modelling procedures. The variances were used to estimate between-session reliabilities, within-session reliabilities and total reliabilities. Within-session reliabilities were substantially higher than between-session reliabilities, which in turn was higher than total reliabilities at all bite positions. Reliabilities were highest at the incisor bite position. Not controlling for age effects substantially overestimated total reliability at all bite positions. After controlling for age effects, total reliabilities of repeated maximum bite forces were low to moderate. © 2009 Blackwell Publishing Ltd.Ítem Reliability of maximum bite force measurements in age-varying populations(WILEY-BLACKWELL PUBLISHING, INC, 2009-11-01) RoldÁn, S.; Buschang, P.H.; Isaza Saldarriaga, J.F.; Throckmorton, G.; Universidad EAFIT. Departamento de Ingeniería Mecánica; Bioingeniería GIB (CES – EAFIT)Summary In order for bite forces to be used clinically, they must be reliable. While bite force transducers are accurate and precise during bench tests, widely varying reliabilities of intra-oral bite forces have been reported when measured in human subjects. Because few studies have reported total reliability, the clinical use of intra-oral bite forces measurements remains questionable. The purposes of this study were to (i) estimate total reliability, including both within- and between-session reliabilities, of repeated maximum incisor and molar bite force measurements and (ii) demonstrate how extraneous variation affects reliability by comparing estimates for which the effects of age have and have not been controlled. A sample of 28 healthy subjects with Class I normal occlusion (seven subjects in each of four age groups: 5, 8, 11 and 14 years) performed two sessions approximately 90 min apart. Each session consisted of three maximum voluntary bites at three bite positions (incisor and right and left molars). For each bite position, between-subject variance (true variance), between-session variance and within-session variance were calculated using Multilevel modelling procedures. The variances were used to estimate between-session reliabilities, within-session reliabilities and total reliabilities. Within-session reliabilities were substantially higher than between-session reliabilities, which in turn was higher than total reliabilities at all bite positions. Reliabilities were highest at the incisor bite position. Not controlling for age effects substantially overestimated total reliability at all bite positions. After controlling for age effects, total reliabilities of repeated maximum bite forces were low to moderate. © 2009 Blackwell Publishing Ltd.Ítem Time dependent deformation behavior of dentin(PERGAMON-ELSEVIER SCIENCE LTD, 2017-04-01) Montoya C; Arola D; Ossa EA; Montoya C; Arola D; Ossa EA; Universidad EAFIT. Departamento de Ingeniería de Producción; Materiales de IngenieríaObjective The viscoelastic behavior of dentin and its ability to undergo time dependent deformation are considered to be important to oral functions and its capacity to resist fracture. There are spatial variations in the microstructure of dentin within the crown, which could be important to the viscous behavior. However, a spatially resolved description for the viscoelastic behavior of coronal dentin has not been reported. Methods In this investigation spherical indentations were made in three regions of coronal dentin including the outer, middle and inner regions. Power law relations were developed to quantitatively describe the stress-strain responses of the tissue. Results Results showed that the deformation behavior was strongly dependent on the composition (mineral to collagen ratio) and microstructure (tubule density), which contributed to an increase in the rate of viscous deformation with increasing proximity to the pulp. Conclusions A model accounting for spatial variations in composition and microstructure was developed to describe the steady-state time dependent deformation behavior of coronal dentin, and a good agreement was found with the experimental results. © 2017 Elsevier LtdÍtem Using fear appeals in warning labels to promote responsible gambling among VLT players: the key role of depth of information processing.(Kluwer Academic Publishers / Plenum, 2010-12-01) Munoz Y; Chebat JC; Suissa JAVideo lottery terminals (VLT) are a highly lucrative gambling format, but at the same time they are among the most hazardous. Previous research has shown that threatening warnings may be an appropriate approach for promoting protective behavior. The present study explores the potential benefits of threatening warnings in the fight against compulsive gambling. A 4 x 2 factorial design experiment was used to test our model based on both Elaboration Likelihood Model and Protection Motivation Theory. 258 VLT adult players (58% males, 42% females) with various degrees of problem gambling were exposed to three threat levels (plus a control condition) from two different sources (i.e., either a medical source or a source related to the provider of VLT's). Our results show that both higher threat warnings and the medical source of warnings enhance Depth of Information Processing. It was also found that Depth of Information Processing affects positively attitude change and compliance intentions. The theoretical and managerial implications are discussed.