How does arch form and interproximal contact size affect the 3D displacements and rotations of teeth: a finite element analysis.

OBJECTIVE: The objective of this study was to determine how arch form and interproximal contact size displace mandibular teeth subjected to an anterior component of force (ACF). METHODS: Nine finite element models (FEM) of the mandibular arch were developed using Ansys® v. 16.0 software. They were designed to evaluate the effects of three arch forms (triangular, oval, and square) and three contact sizes (point-to-point, 1 mm diameter, and 2 mm diameter). All nine models were subjected to an ACF of 53.8 N (5486 gm). Three-dimensional tooth rotations and displacements of the mandibular teeth were evaluated, from the right first molar to the left first molar. RESULTS: Arch form had a greater effect on tooth movements than contact size. Triangular arches and point-to-point contacts produced the greatest displacements and rotations of teeth. Oval arches with 2 mm wide interproximal contact points showed the greatest stability. The right first premolar showed the greatest displacements in all of the models. CONCLUSIONS: Arch form and contact size affect interproximal tooth stability. Teeth are least stable in narrow arches with point-to-point interproximal contacts, and most stable in wider arches with larger contacts.

How does arch form and interproximal contact size affect the 3D displacements and rotations of teeth: a finite element analysis

ABSTRACT Objective: The objective of this study was to determine how arch form and interproximal contact size displace mandibular teeth subjected to an anterior component of force (ACF). Methods: Nine finite element models (FEM) of the mandibular arch were developed using Ansys® v. 16.0 software. They were designed to evaluate the effects of three arch forms (triangular, oval, and square) and three contact sizes (point-to-point, 1 mm diameter, and 2 mm diameter). All nine models were subjected to an ACF of 53.8 N (5486 gm). Three-dimensional tooth rotations and displacements of the mandibular teeth were evaluated, from the right first molar to the left first molar. Results: Arch form had a greater effect on tooth movements than contact size. Triangular arches and point-to-point contacts produced the greatest displacements and rotations of teeth. Oval arches with 2 mm wide interproximal contact points showed the greatest stability. The right first premolar showed the greatest displacements in all of the models. Conclusions: Arch form and contact size affect interproximal tooth stability. Teeth are least stable in narrow arches with point-to-point interproximal contacts, and most stable in wider arches with larger contacts.

RESUMO Objetivo: O objetivo deste estudo foi determinar como o formato da arcada e o tamanho do contato interproximal deslocam os dentes inferiores submetidos a um componente anterior de força (CAF). Métodos: Nove modelos de elementos finitos (MEF) da arcada inferior foram desenvolvidos utilizando o software Ansys® v. 16.0. Eles foram projetados para avaliar os efeitos de três formatos de arcada (triangular, oval e quadrado) e três tamanhos de contato interproximal (ponto a ponto, 1 mm de diâmetro e 2 mm de diâmetro). Todos os nove modelos foram submetidos a um CAF de 53,8 N (5486 gm). Foram avaliados tridimensionalmente as rotações dentárias e os deslocamentos dos dentes inferiores, do primeiro molar direito ao primeiro molar esquerdo. Resultados: A forma da arcada teve um efeito maior no movimento dos dentes do que o tamanho do contato interproximal. Arcadas triangulares e contatos ponto a ponto produziram os maiores deslocamentos e rotações dos dentes. Arcadas ovais com pontos de contato interproximal de 2 mm de largura apresentaram maior estabilidade. O primeiro pré-molar direito apresentou os maiores deslocamentos em todos os modelos. Conclusões: O formato da arcada e o tamanho do contato interproximal afetam a estabilidade dos dentes. Os dentes foram menos estáveis nas arcadas estreitas com contatos interproximais ponto a ponto, e mais estáveis nas arcadas mais largas com contatos maiores.

Bio-structural monitoring of bone mineral alterations through electromechanical impedance measurements of a Piezo-device joined to a tooth.

Bone presents different systemic functionalities as calcium phosphate reservoir, organ protection, among others. For that reason, the bone health conditions are essential to keep in equilibrium the metabolism of several body systems. Different technologies exist to diagnose bone conditions with invasive methods based on ionizing radiation. Therefore, there is a challenge to develop new ways to evaluate bone alterations in a noninvasive form. This study shows the assessment of a piezo-actuated device acting on a human tooth for the bio-monitoring of bone alterations. The bone diagnosis is performed by applying the electromechanical impedance technique (EMI), commonly used in structural health monitoring. For the experimental tests, five bone samples were prepared, and one was chosen as the monitoring. All samples were put in a decalcifying substance (TBD1 acid-base) at different times to emulate localized bone mineral alterations. Bone reductions were computed by using X-ray micro-computed tomography analyzing the morphometry. Electrical resistance measurements (piezo-device) were taken for the monitoring specimen meanwhile it was partially decalcified during 8520 seconds. In the frequency spectrum, several observation windows showed that the bone alterations gradually changed the electrical resistance signals which were quantified statistically. Results evidenced that the bone density changes are correlated with the electrical resistance measurements; these changes presented an exponential behavior as much as in the calculated index, and bone mineral reduction. The results demonstrated that bone alterations exhibit linear dependence with the computed statistical indexes. This result confirms that it is possible to observe the bone changes from the teeth as a future application.

Correction to: Bio-structural monitoring of bone mineral alterations through electromechanical impedance measurements of a Piezo-device joined to a tooth.

[This corrects the article DOI: 10.1007/s13534-020-00170-9.].

Are maximum bite forces of subjects 7 to 17 years of age related to malocclusion?

OBJECTIVE: To determine the effects of occlusion on maximum bite force of growing subjects. MATERIALS AND METHODS: Incisor and first molar bite force of children and adolescents was evaluated. Four cohorts were measured annually for 3 years, starting at approximately 7, 9, 12, and 15 years of age, respectively. The initial sample included 182 females and 198 males; there were 130 subjects with normal occlusion, 111 with Class I malocclusion, and 139 with Class II malocclusion. Multilevel analyses were performed to model the growth changes and compare groups. RESULTS: Maximum bite force increased significantly (P < .05) over time. Incisal forces peaked at 14.3 and 15.3 years of age for females and males, respectively. Maximum molar bite force peaked at 16 years for both males and females. Subjects with normal occlusion had significantly higher bite force than subjects with malocclusion. Maximum molar bite force exhibited a significant testing effect, with forces increasing 2.6 kg each year that the tests were repeated. CONCLUSIONS: Malocclusion has a detrimental effect on bite force. Changes in maximum bite force are also due to age, sex, and repeated testing.

Prevalencia de manchas blancas antes y después del tratamiento de ortodoncia / Prevalence of white spot lesions before and after orthodontic treatment

Resumen Introducción y objetivo: La aparatología de ortodoncia correctiva es un factor de riesgo para caries dental, facilitar su diagnóstico, prevención y control debe ser parte de la formación en esta especialidad. El propósito de este estudio fue evaluar la prevalencia de manchas blancas antes y después del tratamiento de ortodoncia en pacientes entre 10 y 22 años mediante fotografías digitales. Materiales y métodos: Se evaluaron fotografías iniciales y finales de 87 pacientes seleccionados, y modelos finales de 59 pacientes. La información recolectada fue: edad, sexo, tamaño de corona clínica, y presencia de manchas blancas en los 12 dientes anteriores; se utilizaron los criterios ICDAS para determinar la prevalencia de lesiones de mancha blanca (d2) y microcavidad en el esmalte (d3). Resultados: El 26,4% de los pacientes desarrolló lesiones de mancha blanca durante el tratamiento de ortodoncia, no hubo diferencias significativas en la distribución por cuadrantes ni por género, la prevalencia de manchas blancas fue mayor en el tercio gingival, en el canino superior derecho y en los dientes con tamaño de corona clínica más grande. Conclusión: La prevalencia de mancha blanca tuvo un aumento importante durante el tratamiento de ortodoncia con una distribución homogénea según sexo. El ortodoncista debe estar atento y orientar estrategias preventivas en sus pacientes.

Abstract Introduction and objective: Orthodontic fixed appliances are a risk factor for dental caries, and thus the understanding its prevention, diagnosis and treatment should be an integral part of specialty training in orthodontics. The purpose of this study was to evaluate the prevalence of white spot lesions before and after orthodontic treatment in patients between 10 and 22 years of age using digital photographs. Materials and methods: Initial and final photographs of 87 patients and final casts of 59 patients were evaluated. Chart information included: Age, sex, clinical crown size, and presence of white spot lesions in all 12 anterior teeth; ICDAS criteria was used to determine the prevalence of white spot lesions (d2) and enamel micro cavity (d3). Results: 26.4% of patients developed white spot lesions during orthodontic treatment; there was no significant difference in the distribution by quadrants or gender; the prevalence of white spot lesions was higher in gingival third, upper right canine and teeth with greater clinical crown size. Conclusion: Prevalence of white spot lesions increased during the orthodontic treatment with a homogenous distribution by sex. Orthodontists must to be alert and develop preventive strategies in these patients.

Estabilidad de los miniimplantes en Ortodoncia. "Biología ósea y Biomecánica" / Miniimplant stability in Orthodontics. "Bone Biology and Biomechanics"

El anclaje ha sido un aspecto crucial para la mayoría de los tratamientos de Ortodoncia. En las últimas dos décadas, el anclaje con miniimplantes ha aumentado el espectro de posibilidades para muchos tipos de tratamientos por presentar numerosas ventajas y pocas desventajas. Este artículo pretende hacer una revisión de literatura sobre los mecanismos de la biología ósea básica, como los aspectos mecánicos los activan y modulan; como se genera la estabilidad primaria y secundaria, como incide de manera crítica el porcentaje de éxito con el uso de los miniimplantes y como se ha estudiado esta interrelación por medio de modelos con elementos finitos.

Anchorage is crucial in most orthodontic treatments. During the last two decades, anchorage with mini-screw implants has increased the number of possibilities for many different types of orthodontic treatments. The aim of this paper is to present a literature review regarding how bone biology processes are elicited and modulated; how primary and secondary stability influence the success rate when mini-screw implants are used; and how this relation has been studied by means of the finite element method.

Método de superposición estructural de Björk para evaluar crecimiento y desarrollo craneofacial / Björk structural superimposition method to evaluate craniofacial growth and development

La superposición cefalométrica es una herramienta indispensable en la práctica de la Ortodoncia ya que permite evaluar los cambios que sufre el complejo craneofacial a través del proceso de crecimiento y desarrollo o aquellos cambios logrados mediante un tratamiento. En la literatura se han descrito múltiples técnicas de superposición cefalométrica; la mayoría de ellas utilizan como puntos de referencia zonas anatómicas poco estables durante el periodo de crecimiento y desarrollo. El doctor Björk describió una técnica de superposición cefalométrica basada en estudios con implantes metálicos, lo cual permitió identificar puntos de referencia y zonas anatómicas mas estables durante este periodo, por lo que permite medir y valorar los cambios craneofaciales de una manera mas confiable. El Objetivo de este articulo es describir la técnica de superposición estructural de Björk para su utilización como herramienta en la practica clínica e investigativa de la Ortodoncia.

Cephalometric superimposition is a critical tool in Orthodontics when evaluating changes affecting the craniofacial complex through the process of growth and development, or those obtained with treatment. Several cephalometric superimposition techniques have been reported previously, but most of them use unstable anatomical landmarks as reference areas or points to establish changes during growth and development. Björk's method describes a cephalometric superimposition technique based on studies with metal implants which allowed to identify stable reference points during the growth and therefore enable the possibility of measuring and evaluating craniofacial changes in amore reliable manner. The objective of this article is to describe Björk structural superimposition method as a tool in clinical practice and research in Orthodontics.

Evaluación de la confiabilidad del índice PAR en modelos de estudio físicos y digitales / Reliability assessment of PAR index plaster and digital study models

Introducción y objetivo: El índice PAR evalúa los resultados del tratamiento de ortodoncia en términos de mejora y la calidad técnica de la atención. Se puede utilizar para evaluar las normas de tratamiento de ortodoncia. Una buena oclusión tiene un récord nominal de menos de 5 puntos PAR. El objetivo de este estudio es evaluar la confiabilidad del índice PAR medido en los modelos dentales digitales y físicos para el diagnóstico de problemas oclusales. Materiales y métodos: Este estudio se realizó en 21 modelos de estudio correspondientes a individuos distribuidos equitativamente tanto del sexo femenino como masculino, con diferentes rangos de edades entre 6 y 17 años y en tres tipos de maloclusión (clase I, clase II y oclusiones ideales) escogidos al azar entre 480 modelos disponibles en el grupo de investigación del GIB. Para la medición digital a los modelos de estudio se les tomo un registro de mordida con cera para modelar; las mediciones manuales se realizaron con un calibrador digital y la regla correspondiente al índice PAR; se calibraron 2 investigadores en forma ciega en dos momentos diferentes para la realización de las mediciones. Resultados: Se encontró una excelente confiabilidad de las medidas del índice PAR entre los modelos físicos y los digitales con un coeficiente de correlación intra clase (CCI=0,99) y un intervalo de confianza de 95%. (0,98; 0,99) Conclusión: La medición del índice PAR es igualmente confiable cundo se mide en modelos de yeso que en modelos digitales.

Introduction and objective: The PAR index evaluates the results of orthodontic treatment in terms of improving the technical quality of care. It can be used to assess orthodontic treatment standards. A good occlusion has a nominal record of less than 5 PAR points. The aim of this study was to assess the reliability of the PAR index measured in physical and digital dental models for diagnosing occlusal problems. Materials and methods: This study was conducted in 21 study models of both female and male patients, with different age ranges between 6 and 17 years and three types of malocclusion (Class I, Class II and ideal occlusions) randomly selected from 480 models available in the IPF Research Group. In order to make digital measurements of study models bite registration with modeling wax were taken; manual measurements were made with a digital caliper and ruler for the PAR index; two researchers were blindly standardized at two different times in order to perform the measurements. Results: An excellent reliability of PAR index measurements was observed between physical and digital models with intraclass correlation coefficient (ICC = 0,99) and a confidence interval of 95%. (0,98; 0,99). Conclusions: PAR Index measurements are equally reliable when measured on plaster or digital models.

Mixed longitudinal evaluation of masticatory performance in children 6 to 17 years of age.

INTRODUCTION: The purposes of this study were to determine (1) how masticatory performance changes with age, (2) whether masticatory performance differs between the sexes, and (3) whether patterns of masticatory performance differ among subjects with various types of malocclusion. METHODS: A total of 450 children and adolescents (244 boys, 206 girls) were assigned to 4 age cohorts (ages 6, 9, 12, and 15 years) and followed for 3 consecutive years. The subjects were selected based on having about equal numbers of boys and girls, and about equal numbers of subjects with normal occlusion and Class I and Class II malocclusions. Masticatory performance was assessed by using the artificial food CutterSil (Heraeus Kulze, South Bend, Ind). The peer assessment rating index was used to quantify the severity of the malocclusions. RESULTS: Median particle size (MPS) decreased significantly from 6 to 17 years of age. There were no statistically significant differences in MPS between the 3 occlusal groups, but there were significant sex differences, with girls having smaller MPS than boys. Multilevel analysis showed greater decreases in MPS between 6 and 9 years, and after 12 years of age, than between 9 and 12 years of age. There were no significant correlations between MPS and the weighted peer assessment rating index. MPS showed significant intercorrelations between measures of MPS obtained at years 1, 2, and 3, with correlations tending to be highest for the oldest age cohort. CONCLUSIONS: Masticatory performance improves with age, and the changes appear to be influenced by the loss of the deciduous teeth during the late mixed dentition phase of dental development. Although there are limited sex differences in masticatory performance among subjects 6 to 17 years of age, mild forms of Class I and Class II malocclusions have little or no effect on masticatory performance.

A mixed longitudinal anthropometric study of craniofacial growth of Colombian mestizos 6-17 years of age.

The purpose of this study was to evaluate the craniofacial growth of Colombian mestizos. Four age cohorts, including a total of 458 children and adolescents (262 males and 216 females), were included in this mixed-longitudinal study. The cohorts were first measured at ages 6, 9, 12, and 15 and every year thereafter for 3 years. Eight anthropometric measurements were taken, including three cranial (head perimeter, head width, and head length), two craniofacial (maxillary and mandibular length), and three facial (face height, bizygomatic width, and bigonial width). Multilevel analyses showed that all dimensions increased between 6 and 17 years of age. The cranium grew less than the craniofacial, which in turn grew less than the facial dimensions. In addition, vertical dimensions showed more growth than antero-posterior dimensions, which in turn grew more than transverse dimensions. None of the measurement showed statistically significant growth differences between subjects with normal occlusion and Class I or Class II malocclusions. Males were generally larger than females and showed greater growth rates. Except for facial width, whose yearly velocities decreased regularly with age, an adolescent growth spurt was evident for most of the male measurements. Yearly velocities for females followed a simpler decelerating pattern. The results provide reference data for Colombian mestizos, for whom normative data of other ethnic groups are not applicable. While occlusion had little or no effect, there were gender differences, as well as important growth differences between cranial and facial measurements.

Desarrollo de un modelo FEM del complejo craneofacial para simular tratamientos en CLASE III esqueletica / Craniofacial FEM for skeletal CLASS III malocclusion treatments simulation

Introducción y Objetivo: En bioingeniería hay limitantes en la realización de experimentos sobrehumanos por lo que usa el método de elementos finitos. Describir el método de reconstrucción de un cráneo completo para desarrollar un modelo de elementos finitos para posteriormente simular la acción de diferentes dispositivos para el tratamiento del prognatismo mandibular.

Introducction and Objetive: In bioengineering, experiments on humans are limited. Given this,finite element method is needed. To describe the method of reconstruction of a skull to develop afinite element model that allows simulating the effect of different orthodontic devices for the treatmentof mandibular prognathism.

Maxillary and mandibular arch widths of Colombians.

INTRODUCTION: This study provides reference data and evaluates the potential of using regression models to predict maxillary and mandibular arch widths. METHODS: A total of 473 Colombian mestizos, aged 5 to 17 years, with normal occlusions and malocclusions (Class I and Class II Division 1) were evaluated. Arch widths and tooth sizes were measured on each subject's dental casts. Anthropometric measurements of body size, facial breadth, and facial height were used, along with tooth sizes, to develop multiple regressions for predicting arch widths. RESULTS: Analyses showed that Class II subjects had significantly (P < 0.05) narrower anterior maxillary widths than those with normal occlusion or Class I malocclusion. Class I subjects had narrower interpremolar widths than those with normal occlusion or Class II malocclusion. Boys had significantly (P < 0.001) wider arches than girls, especially in the posterior aspects. Older children had significantly wider arches than younger children, with intermolar and interpremolar widths having the largest and smallest age effects, respectively. Regression analyses of subjects with normal occlusion showed that 2 to 5 variables combined to explain 36% to 64% of the variation in arch widths, with the sizes of the maxillary incisors and bigonial width explaining most of the variation. CONCLUSIONS: When applied to subjects with malocclusion, the predictions indicate transverse deficiencies in the premolar region of Class I subjects and deficiencies in the anterior maxilla of Class II subjects. Predictions based on Pont's index, the Schwarz analysis, or the McNamara rule of thumb were biased and less reliable than those based on the regressions.

Design and construction of a transducer for bite force registration.

This study describes the development of a system for quantification of human biting forces by (1) determining the mechanical properties of an epoxy resin reinforced with carbon fiber, (2) establishing the transducer's optimal dimensions to accommodate teeth of various widths while minimizing transducer thickness, and (3) determining the optimal location of strain gages using a series of mechanical resistance and finite element (FE) analyses. The optimal strain gage location was defined as the position that produced the least difference in strain pattern when the load was applied by teeth with two different surface areas. The result is a 7.3-mm-thick transducer with a maximum load capacity beyond any expected maximum bite force (1500N). This system includes a graphic interface that easily allows acquisition and registration of bite force by any health-sciences or engineering professional.

Sistema electrónico de adquisición para procesar y almacenar datos de fuerza oclusal(AU) / Electronic System for the acquisition, processing and storage of bite force date

Introducción y Objetivo: El presente artículo describe el diseño, construcción de un sistema electrónico de adquisición de datos portátil para un sensor de fuerza de mordida con una capacidad de 200 Kg. que previamente fue desarrollado (Gnatodinamómetro-GIB), con el fin de almacenar datos de fuerza oclusal en personas, las cuales, son identificadas por su nombre y un código de 4 dígitos. Materiales y Métodos: El sistema está configurado para almacenar registros de mordida de hasta 60 personas, donde cada uno de los registros puede contener hasta 6 medidas de fuerza oclusal. La información es almacenada en memoria y posteriormente puede ser descargada a un computador mediante el puerto RS232, a partir de una aplicación de software desarrollada en Borland-Delphi. Los archivos descargados están en formato de texto plano (*.txt), lo cual facilitó su análisis mediante una herramienta convencional de hoja de cálculo. Resultados: Se obtuvo un artefacto electrónico portátil, con unas medidas de 1 9x14x5 cm y con un peso de 528 gramos. La calibración del Gnatodinamómetro arrojó un coeficiente de determinación R2 de 0.9997 y una resolución de 150 gr. En la prueba de reproducibilidad en pacientes, se encontró que las medidas de fuerza oclusal para cada una de las zonas evaluadas: molar izquierda, molar derecha e incisivos, se obtuvo un coeficiente de correlación intraclase que osciló entre 0.9 y 0.97. Conclusión: Se desarrolló un sistema versátil y liviano, el cual pudo ser transportado fácilmente hacia el lugar donde se encontraban las personas que fueron sometidas a pruebas de fuerza de mordida, que a su vez, garantizó la seguridad en el momento de adquirir y almacenar la información.

Introduction and Objetive: This study describes the design and construction of an electronic system for a bite force sensor data acquisition, (Gnathodynamometer, GIB), that had been previously developed with the aim of storing human oclusal force data. The subjects are identified by their name and a 4 digit codeo. Materials and Methods: The system was developed to store bite force records of up to 60 people with 6 measurements per individual. The information can be stored in a memory system and can be downloaded to any computer by means of an RS232 port by means of a software application that was developed on a Borland-Delphi platform. The files are then formatted by the software application to a plain text (*.txt) which facilitates the data analysis by conventional tools. Results: A portable electronic device was obtained with the following measures: 1 9x14x5 cm and 528 gr of weight. The Gnathodynamometer calibration showed a determination coefficient R2 of 0.9997 and a resolution of 150gr. The reproducibility test in patients, showed an intraclass correlation coefficient for bite force between 0.9 and 0.97. Conclusion: A light and easy to operate system was developed that could be taken to the schools were bite force data gathering is required to be done in a secure an efficient way.

Diseño y fabricación de un nuevo distractor curvo de sínfisis mandibular para transporte óseo / Design and manufacture of a new curve symphyseal distractor for mandibular bone transport

Son activados principalmente por el operador diariamente; teniendo como ventaja estos últimos la ausencia de cicatrices cutáneas permanentes. El objetivo principal de este estudio fue diseñar y fabricar un prototipo de distractor curvo de sínfisis, intraoral para reconstrucción mandibular. Materiales y Métodos: Se realizaron pruebas técnicas: modelo elementos finitos del distractor y cuerpo mandibular, generando una malla formada por 80.000 elementos con restricciones en el condilo mandibular, dos tornillos a cada lado de la placa y cuatro a cada lado del distractor en todos los grados de libertad; se aplicaron fuerzas de 248N a la zona. Finalmente, se realizó la prueba de instalación en cadáver para verificar la técnica quirúrgica y su ergonomía. Resultados: Se observó una distribución uniforme de esfuerzos para todo el sistema mandíbula- distractor, garantizando su resistencia y estabilidad estructural. Conclusiones: El dispositivo es resistente a las fuerzas de masticación, es de facial instalación y activación; permite la reconstrucción de segmentos curvos de amplia longitud.

Introduction and Objective: Currently, there are extra-and intra devices, which are mainly triggered by the operator daily, taking advantage as the latter no permanent scars skin. The main objective of this study was to design and manufacture a prototype of intraoral curve symphyseal distractor for mandibular reconstruction. Materials and Methods: The following technical tests were carried out: finite element model of the distractor and mandibular body creating a net of 80,000 elements with restrictions in the mandibular condyle, two screws on each side of the plate and four on each side of the distractor in every degree of freedom. 248N forces were applied to the zone. Finally, the installation test on a cadaver was done in order to verify the surgical technique and its ergonomy. Results: A uniform distribution of strains was observed for all the mandibular-distractor system, guarantying its resistance and structural stability. Conclusions: The device is resistant to masticatory forces; it is easy to install and to activate and allows the reconstruction of wide range curved segments.

Ejecución de un sistema piloto de tele-radiología en Medellín, Colombia / Implementing a teleradiology pilot system in Medellín, Colombia

Objetivo: Aplicar un sistema piloto de tele-radiología en la ciudad de Medellín con software de acceso remoto que permita la comunicación e interpretación a distancia de imágenes biomédicas. Materiales y métodos: Se utilizaron imágenes de estudios de resonancia magnética y tomografía computadorizada almacenados en formato DICOM. Los datos se transmitieron en una red punto a punto mediante líneas de red digital de servicios integrados (RDSI) entre dos centros de diagnóstico radiológico. El sistema se llevó a cabo bajo arquitectura PC basada en Intel x86 con sistema operativo Windows® 2000. Resultados: Para la lectura y visualización local de imágenes almacenadas en formato DICOM, se desarrolló una aplicación en Java con funciones que permiten su manipulación y la opción de exportar a otros formatos como JPEG, TIFF y BMP. Conclusiones: El sistema permitió en modalidades como tomografía computadorizada (TC) e imagen por resonancia magnética (RM) un diagnóstico e interpretación remota clínicamente confiables, con tiempos de respuesta aceptables para las necesidades y modo de actuar reales de los centros radiológicos participantes.

Objective: To implement a teleradiology pilot system in Medellín city using software for remote access, this allows the communication and interpretation of biomedical images at distance. Materials and methods: Images from different magnetic resonance and computed tomography studies stored in DICOM format were used. Data were transmitted in a point-to-point network using an integrated services digital network (ISDN) line between two radiological diagnostic centers. The system was developed under PC Intel’s x86 architecture, with Windows® 2000 as the operating system. Results: In order to read and visualize images stored in DICOM format, a Java application with functions that allow their manipulation and the option to export them to other formats such as JPEG, TIFF and BMP was developed. Conclusion: The system allows a clinically reliable diagnostic and remote interpretation for modalities such as computed tomography (CT) and magnetic resonance (MR) images, with acceptable response times.

Masticatory performance in children and adolescents with Class I and II malocclusions.

It is not fully understood whether masticatory performance is compromised in individuals with the more common forms of malocclusion (i.e. Class I and Class II). The aim of this prospective investigation was to establish the relationships between masticatory performance, malocclusion (type and severity), age, body size and gender, in children and adolescents. A total of 335 individuals were examined at the average ages of 6, 9, 12 and 15 years. Each subject's occlusal status was described by Angle classification and by the Peer Assessment Ratio (PAR) index. Masticatory performance was quantified by the median particle size (MPS) and the broadness of particle distribution using artificial food. Masticatory performance improved significantly with age. The 6-year-old children were less able to break down the food particles (MPS 4.20 mm2) than the 15 year olds (MPS 3.24 mm2). Analysis of covariance showed that age differences in performance are related to an increase in body size. There were statistically significant differences in masticatory performance between children with normal occlusion and those with a Class I malocclusion; no differences were found between normal occlusion and Class II malocclusion. Gender differences did not explain the variation in masticatory performance. It is concluded that occlusal indices are not reliable predictors of masticatory performance. Traditional descriptors of malocclusion type and severity apparently cannot explain most of the variation in masticatory performance in children and adolescents.

Dimensiones transversales del arco dental en una población colombiana entre los 7 y 17 años de edad / Transversal dimensions of the dental arch in a Colombian population between 7 and 17 years of age

El propósito de este estudio fue evaluar los posibles factores que pudieran explicar las diferencias en el ancho del arco dental, además de predecir las dimensiones transversales del arco en un grupo de niños colombianos entre los 7 a 17 años de la edad. Para el estudio fueron incluidos un total de 394 niños y adolescentes con oclusión normal para determinar con base en la edad, sexo, la estatura, el tamaño dental y las dimensiones craneofaciales, cuáles serían de mayor peso al momento de predecir las dimensiones del arco dental...

Reconstrucción tridimensional de estructuras óseas a partir de estudios tomográficos para su manipulación en modelos de elementos finitos / Three dimensional reconstruction of osseous structures based on tomographic studies for the manipulation of finite element models

La reconstrucción y visualización tridimensional de estructuras óseas es una herramienta útil para el diagnóstico clínico a partir de imágenes médicas. Además, la aplicación de diferentes técnicas de ingeniería, como el diseño asistido por computador y modelaciones numéricas de dichas estructuras, brindan un apoyo significativo a los profesionales e investigadores del área de la salud para la realización de procedimientos clínicos más acertados. Este artículo presenta un método de reconstrucción tridimensional de estructuras óseas a partir de imágenes topográficas planas en formato DICOM, que consta de un módulo de procesamientos de las imágenes MATLAB 6.5 y un módulo de reconstrucción, manipulación y visualización de estructuras sólidas en el software CAD/CAM ProENGINEER WILDFIRE para su posterior utilización en software de electos finitos...