Examinando por Materia "adolescent"
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Ítem Anteversión pélvica como causa de dolor lumbar, síndrome patelofemoral y dolores del crecimiento(Ediciones Doyma, S.L., 2014-01-01) Vélez-Patiño, J.A.; Ríos-Sánchez, L.M.; Ochoa-Jaramillo, F.L.; Díaz-León, C.A.; Universidad EAFIT. Escuela de Ciencias; Modelado MatemáticoIntroduction: Back pain, patellofemoral syndrome and "growing pains" are increasingly common in children and adolescents, both with incidence and precocity of appearance. In most cases their etiology is unknown. Objective: The objective of this research was to explore the possible association of these three entities with pelvic anteversion. Methods: This is a cross-sectional study with case-control analysis, comprising a group of 30 symptomatic children aged between 6 and 17 years (cases) who had consulted for low back pain, "growing pains" or sore knees, and a control group of 30 children with no history of pain in these areas (controls). To measure the position of the pelvis and other biomechanical variables a software programme was developed that quantifies these measurements from reflective markings located on specific anatomical landmarks of each child. Other measurements were obtained through semiological tests and interviews with children and their parents. Results: Children and adolescents with pain had more pelvic anteversion compared with controls (mean 13.3 and 5.4 degrees, p < 0.001). They also had less strength in muscles: Lumbar extensor, abdominals, psoas and diaphragm. We found that psoas is the muscle most responsible for pelvis anteversion in symptomatic group. Compared with children without pain, those with back pain, patellofemoral syndrome or "growing pains" have 4.2 times more frequent poor or regular strength in the column extensor muscles. They also have nearly 18 times as likely to have a pelvic angle greater than 10 degrees compared with no pain children. Conclusions: Children and adolescents who suffer from back pain, patellofemoral syndrome and "growing pains" have increased pelvic anteversion and lower muscle strength, mainly in the thoracolumbar spine extensors, abdominals, diaphragm and psoas. The study found that the psoas muscle is most responsible for the development of pelvis anteversion. Pelvic anteversion is associated with low back pain, patellofemoral pain syndrome and "growing pains". © 2015 Arán Ediciones, S.L.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 Ltd