1D Finite element model using rod element applied to muscle behavior simulation

[EN]The objective of this study is to implement a new simplified model of a muscle, based on a 1D element, rod type, used in most common analysis, instead of a 3D mesh of the muscle geometry. The main advantages of this new method for modeling muscles is that several position of a joint, where the muscle is involved, could be analyzed without any added effort to the original meshing of the model. We only need to locate the bones involved in the joint in their new position, and so the muscles will move to their right position. 3D models allow us to study in a more detailed manner the muscle stress maps, deformations, but the main issue we must work on is the need of re-meshing the 3D geometry any time the joint changes in position. With this simplified method, only its insertion points, the section and the length, define the muscle, in the FEA. And none of the changes when the joint changes in position

Multi-criteria selection of structural adhesives to bond ABS parts obtained by rapid prototyping

One of the most used methods in rapidprototyping is Fused Deposition Modeling (FDM), which provides components with a reasonable strength in plastic materials such as ABS and has a low environmental impact. However, the FDM process exhibits low levels of surface finishing, difficulty in getting complex and/or small geometries and low consistency in “slim” elements of the parts. Furthermore, “cantilever” elements need large material structures to be supported. The solution of these deficiencies requires a comprehensive review of the three-dimensional part design to enhance advantages and performances of FDM and reduce their constraints. As a key feature of this redesign a novel method of construction by assembling parts with structuraladhesive joints is proposed. These adhesive joints should be designed specifically to fit the plastic substrate and the FDM manufacturing technology. To achieve this, the most suitable structuraladhesiveselection is firstly required. Therefore, the present work analyzes five different families of adhesives (cyanoacrylate, polyurethane, epoxy, acrylic and silicone), and, by means of the application of technical multi-criteria decision analysis based on the analytic hierarchy process (AHP), to select the structuraladhesive that better conjugates mechanical benefits and adaptation to the FDM manufacturing proces

Differential impacts of caries classification in children and adults : a comparison of ICDAS and DMF-T

The aim of this study was to describe and compare findings regarding the prevalence and severity of dental caries when using ICDAS and DMFT/dmft in an epidemiological study with children and their mothers. This cross-sectional study evaluated 150 preschoolers and their mothers. Data were collected with ICDAS and then transformed into DMFT/dmft. ICDAS scores related to caries were analyzed according to three different cut-off-points: CP1 (0-healthy/1-6-caries), CP2 (0-1-healthy/2-6-caries) and CP3 (0-2-healthy/3-6- caries), representing the D/d of DMFT/dmft. ICDAS codes regarding restorations, except sealants, were considered the F/f and the code 97 as the M/m of DMFT/dmft index. Prevalence of caries and its severity with ICDAS were 92%, 84% and 31.3% in children and 97.3%, 96.6% and 80% in adults according to CP1/CP2/CP3, respectively. Admitting CP3 as the standard for data transformation of ICDAS in DMFT/dmft, it was observed that DMFT/dmft index would underestimate 60% of non-cavitated lesions in children and 16.6% in adults. The DMFT/dmft underestimated the presence of disease to disregard non-cavitated lesions for the pediatric population evaluated. The choice of which is the best index for epidemiological surveys will depend on the purpose of the research and the target population: if it is to estimate the needs of the population to determine clinical care in children and adults, the DMFT/dmft may be sufficient. However, if the objective is to have a more comprehensive diagnosis of caries at the population level in order to develop preventive strategies, to halt and reverse the disease, the detection of non-cavitated-lesions becomes important, mainly in young children

Design of Thermoplastic Oral Appliance With Mouth Opening Control to Treat Obstructive Sleep Apnea

[EN]Obstructive Sleep apnea is associated with daytime sleepiness, increased motor vehicle accidents, heart failure and stroke. Treatment options include weight loss, positive airway pressure, pharyngeal and orthognatic surgery. However, selected patients have good response to oral appliances devices that intended to protrude and stabilize the mandible mechanically during the night in order to reduce the collapsibility of the upper airway. Selection of patients includes primary snoring, mild, moderate and positional apnea. The objective of this paper is to present a new thermoadjustable chair-side oral appliance. Device integrates the best characteristics of custom made and boils and bite previous designs and minimizes inconveniences and possible side effects. The device is a titratable mandibular advancement appliance. It consists of two independent prefabricated trays adaptable to the shape of adult dental arch and linked to each other by a protrusion mechanism. Each tray contains a hard outer shell and a soft thermoplastic resin inner body. The position of the jaw can be adjusted by moving an aluminium rack into, or out from, the guide so the ratchet may get locked into a certain position ensuring the length of the mechanism. The protrusion mechanism is fixed to the splint using small rings that are articulated over a “t” button. The opening of the mouth can be limited by an integrated locking system of the “t” button. Our prototype satisfies the requirements of an effective oral appliance, in terms of retention, comfort, safety and efficacy. It is easy to fit, durable, low cost, quickly titratable, not bulky and easy cleaning. Thermoplastic appliances are specially used like a predictor of treatment response in apnea patients. The device described is a cost-effective introduction to mandibular advancement technology. A qualified dentist or trained sleep doctor could mitigate dental side effects and reduce their incidence

Design and prototype of a control for virtual environment in CHD examination

[EN]The study represents a preliminary step for the complete development of a virtual reality glasses control. This command will have applications for the simulation of the practice of the ultrasound examination in the diagnostic test of Congenital Heart Disease. This will help in the formation of new doctors during their practical class. In this work 3 analyzes were performed. With the functional analysis, the important parts of the control that will be applied in the prototype were removed. In the morphological analysis the final form of the command was developed, constituting a recognizable form for their respective users, and adding the necessary components for their operation. Finally, thanks to the ergonomic analysis, the relationship between the machine and the doctor could be understood

Aplicación de la programación en Autolisp en la enseñanza de la geometría. Curvas trocoidales

En este artículo presentamos las posibilidades que, desde un punto de vista didáctico, ofrece la programación en AutoLISP en la enseñanza de la geometría, en particular en el trazado y aplicación de curvas trocoidales. La idea original consistía en realizar un programa que crease un nuevo comando de AutoCAD capaz de trazar cualquier curva trocoidal –tanto particulares (evolventes y cicloides) como no particulares (epitrocoides, hipotrocoides o peritrocoides)–, con independencia de la situación del punto generador (alargadas, acortadas o normales). La elaboración del programa es relativamente simple. Para obtener todos los puntos de la curva es necesario aplicar siempre las mismas propiedades, lo que hace especialmente aconsejable la automatización del proceso. El programa realizado permite seleccionar sobre la pantalla generatriz y directriz, así como el punto que genera la curva. Se nos ofrece, asimismo, establecer el sentido de giro de la ruleta, la precisión de puntos hallados en cada ciclo (tantos como deseemos o como nuestro ordenador sea capaz de soportar), el número de vueltas y, por último, la posibilidad de apreciar, o no, la generación de la trocoide. Esta última opción permite observar, en la pantalla del ordenador, el giro de la generatriz sobre la directriz y la generación progresiva de la curva. Esta pequeña animación –contenida en un comando de AutoCAD– ha convertido un programa originalmente concebido para el trazado de curvas trocoidales, en una herramienta didáctica

Tratamento odontológico disponível e sua associação com a satisfação com os serviços de atenção primária à saúde acessados por idosos

Objetivo: Esta pesquisa objetiva avaliar se a presença de equipes de saúde bucal nas unidades de atenção primária à saúde do SUS está associada a maior satisfação com o serviço acessado. Material e método: Neste estudo, de delineamento transversal, entrevistaram-se 401 idosos nos distritos Lomba do Pinheiro e Partenon em Porto Alegre, selecionados através de um processo amostral por conglomerados, a partir do sorteio de setores censitários. Resultado: A Regressão de Poisson demonstrou que as variáveis idade e oferta de tratamento odontológico se mantiveram associadas com o desfecho, já as variáveis idade, número de dentes e presença de tratamento odontológico estiveram associados com maiores prevalências à satisfação com o serviço de saúde. Conclusão: Os resultados encontrados trazem novas contribuições para a qualificação do SUS, uma vez que o estudo demonstra a necessidade de valorizar e integrar as equipes de saúde bucal às equipes de APS, pois traz evidências da associação entre a presença da equipe de saúde bucal e a satisfação dos usuários idosos com o serviço de saúde acessado.Objective: This research evaluated whether having dental treatment available in the primary health care centers of the Brazilian Unified Health System was associated with greater satisfaction with the services accessed. The offering of dental care within the health service that elders usually access may improve their satisfaction with the services as a whole. Material and method: In this cross-sectional study, 401 elders living in the districts of Lomba do Pinheiro and Partenon in Porto Alegre, Brazil were interviewed. Elders were selected using a cluster sampling design process from census tract drawings. Result: Poisson Regression revealed that age and dental treatment supply were associated with outcome, and age, number of teeth, and the presence of dental treatment were associated with a higher prevalence of satisfaction with health services. Conclusion: These results provide new contributions for health system qualification because this study demonstrated the importance of having dental treatment available to improve the satisfaction of older people with the Primary Health Care (PHC) services accessed

Impact of Early Childhood Caries and Maternal Behaviors on Oral Health-Related Quality of Life of Children

Objective: To evaluate the impact of early childhood caries, maternal behaviors and associated factors on the oral health-related quality of life (OHRQoL) of preschool children. Material and Methods: This cross- sectional study was conducted with 163 preschool children aged 3-4 old from Porto Alegre, Southern Brazil. Mothers completed the Brazilian version of the Early Childhood Oral Health Impact Scale (ECOHIS) and answered questions about sociodemographic and maternal behaviors characteristics. The severity of dental caries was assessed by ICDAS criteria for evaluated early childhood caries (ECC). A Poisson regression model was used to investigate the association of ECC and associated factors on OHRQoL. Results: A total of 91.4% of preschooler children was ECC (ICDAS ≥ 1). Mean ECOHIS function domain and parental anxiety domain scores were significantly higher in children with dental caries (p<0.05). The adjusted Poisson regression model showed that household income, maternal education, mother’s job status and breastfeeding time was significantly associated with ECOHIS scores. Regarding oral conditions, child caries experience was associated with worsening child and family quality of life (RR 2.21; 95% IC: 1.43-3.41). Conclusion: Our findings suggest that ECC, socioeconomic and maternal behaviors characteristics influence children’s OHRQoL

Analysis of the anisotropy in parts for medical applications created by the superposition of layers of PLA and epoxy resin with the FFF & Robocasting techniques

[EN]The purpose of this study is to analyze the anisotropy of a new additive manufacturing technique that will use thermoplastic material and epoxy resin to create the creation of usable parts for the medical industry. In the article "Novel Technique Based on Fused Filament Fabrication (FFF) and Robocasting to Create Composite Medical Parts", the manufacturing technique was analyzed and it was concluded that the combination of a thermoplastic and an epoxy resin opens a new path in the manufacture of additives since it allows to create pieces with new qualities without being conditioned by the design. In this article we have analyzed specimens that have been printed vertically to obtain a study of the anisotropy and the incidence in the thermoplastic of the inclusion of the epoxy resin with respect to the adhesion between layers. The new system of additive manufacturing has not allowed improving the adhesion between layers of natural PLA but has allowed raising future investigations observing the fracture of the test tubes