Photoelastic And Finite Element Analyses Of Occlusal Loads In Mandibular Body.

This study proposed to evaluate the mandibular biomechanics in the posterior dentition based on experimental and computational analyses. The analyses were performed on a model of human mandible, which was modeled by epoxy resin for photoelastic analysis and by computer-aided design for finite element analysis. To standardize the evaluation, specific areas were determined at the lateral surface of mandibular body. The photoelastic analysis was configured through a vertical load on the first upper molar and fixed support at the ramus of mandible. The same configuration was used in the computer simulation. Force magnitudes of 50, 100, 150, and 200 N were applied to evaluate the bone stress. The stress results presented similar distribution in both analyses, with the more intense stress being at retromolar area and oblique line and alveolar process at molar level. This study presented the similarity of results in the experimental and computational analyses and, thus, showed the high importance of morphology biomechanical characterization at posterior dentition.

Finite-element Analysis Of 3 Situations Of Trauma In The Human Edentulous Mandible.

Maxillofacial trauma resulting from falls in elderly patients is a major social and health care concern. Most of these traumatic events involve mandibular fractures. The aim of this study was to analyze stress distributions from traumatic loads applied on the symphyseal, parasymphyseal, and mandibular body regions in the elderly edentulous mandible using finite-element analysis (FEA). Computerized tomographic analysis of an edentulous macerated human mandible of a patient approximately 65 years old was performed. The bone structure was converted into a 3-dimensional stereolithographic model, which was used to construct the computer-aided design (CAD) geometry for FEA. The mechanical properties of cortical and cancellous bone were characterized as isotropic and elastic structures, respectively, in the CAD model. The condyles were constrained to prevent free movement in the x-, y-, and z-axes during simulation. This enabled the simulation to include the presence of masticatory muscles during trauma. Three different simulations were performed. Loads of 700 N were applied perpendicular to the surface of the cortical bone in the symphyseal, parasymphyseal, and mandibular body regions. The simulation results were evaluated according to equivalent von Mises stress distributions. Traumatic load at the symphyseal region generated low stress levels in the mental region and high stress levels in the mandibular neck. Traumatic load at the parasymphyseal region concentrated the resulting stress close to the mental foramen. Traumatic load in the mandibular body generated extensive stress in the mandibular body, angle, and ramus. FEA enabled precise mapping of the stress distribution in a human elderly edentulous mandible (neck and mandibular angle) in response to 3 different traumatic load conditions. This knowledge can help guide emergency responders as they evaluate patients after a traumatic event.

O ensino de línguas para crianças no contexto educacional brasileiro: breves reflexões e possíveis provisões

This article aims at discussing about the foreign language teaching to young learners, taking the principles of the Sociocultural Theory (Vygotksy, 1978) and of the Communicative Approach (Almeida Filho, 1993, 2005) related to Primary English teaching (Cameron, 2001; Brewster, Ellis & Girard, 2002) as a theoretical references. Considerations about the importance of language learning in childhood will be made, as well as about the role of the grammar, oral language and mother tongue in the process. Likewise, the importance of Teacher Education will be briefly approached. This work is ended with the discussion about some possible procedures in the language teaching processes followed by a brief presentation of possible guidelines based on the bakhtinian notion of discourse genres.

Tradução & aprendizado de língua estrangeira: o ponto de vista do aluno

This paper reports some exemplary data related to a research project on the role of translation in foreign language teaching-learning. The data were collected through a questionnaire administered to 47 Brazilian ESL learners. Specifically, the points of the analysis are: how the translation process is conceived by the students; why and when the translation is used by the learners in classroom situations; mother tongue/foreign language relationships in this specific context, among other aspects. The findings reveal that translation, when used a mediating resource for foreign language teaching-learning, can promote target language management.