Finite-element analysis of 3 situations of trauma in the human edentulous mandible.

PURPOSE: 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). MATERIALS AND METHODS: 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. RESULTS: 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. CONCLUSIONS: 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.

Comparison of gunshot entrance morphologies caused by .40-caliber Smith & Wesson, .380-caliber, and 9-mm Luger bullets: a finite element analysis study.

Firearms can cause fatal wounds, which can be identified by traces on or around the body. However, there are cases where neither the bullet nor gun is found at the crime scene. Ballistic research involving finite element models can reproduce computational biomechanical conditions, without compromising bioethics, as they involve no direct tests on animals or humans. This study aims to compare the morphologies of gunshot entrance holes caused by.40-caliber Smith & Wesson (S&W), .380-caliber, and 9×19-mm Luger bullets. A fully metal-jacketed.40 S&W projectile, a fully metal-jacketed.380 projectile, and a fully metal-jacketed 9×19-mm Luger projectile were computationally fired at the glabellar region of the finite element model from a distance of 10 cm, at perpendicular incidence. The results show different morphologies in the entrance holes produced by the three bullets, using the same skull at the same shot distance. The results and traits of the entrance holes are discussed. Finite element models allow feasible computational ballistic research, which may be useful to forensic experts when comparing and analyzing data related to gunshot wounds in the forehead.

Participação do odontolegista em serviços médico-legais / Participation of the forensic dentist in forensic departments

As contribuições dos cirurgiões-dentistas forenses a métodos científicos de investigação e identificação são importantes e, é essencial a todos os estudantes de odontologia o conhecimento desta área de especialização durante sua passagem pela faculdade; nos EUA, por exemplo, todos os centros de identificação possuem em seu quadro de pessoal um cirurgião-dentista'. A sela turca (sella turcica) é um acidente anatõmico localizado no centro da fossa média do crânio; é uma depressão que se localiza na região do corpo do esfenóide, com o tubérculo da sela em sua parte anterior, uma depressão média chamada fossa hipofisal, e seu limite posterior, o dorsum sel/ae? O crescimento da violência no Brasil, fez das armas de fogo os instrumentos mais utilizados (60%) nos homicídios ocorridos na década de 1990, atingindo o percentual de 70% no ano 2000; em São Paulo, apenas 10% dos homicídios foram cometidos com outros instrumentos na mesma época. No Rio de Janeiro e em Recife a proporção de homicídios por armas de fogo era superior a 80% em 199F Este trabalho realizou um relato de caso que ressaltou a importância do odontolegista no serviço médico legal através da identificação do local de retenção de um projétil de arma de fogo em vítima fatal necropsiada no Departamento Médico Legal (DML) de Vitória-ES.

Stoeckel, Merkley & McGivnel (2007) consider the forensic dentist's contribution to scien- tific methods of investigation and identification of great importance and that is essential to ali dentistry students the knowledge in this area of expertise while undergrad students; also report the presence of a forensic dentist in each of the Forensic Departments in the USA. The turk sell is an anatomical structure placed in the center of the central cranial fossa; it's a depression placed in the region of the sphenoid bone body, with the sell tuberculum in it's anterior portion, a medial depression called hipophisal fossa, and it's posterior limit, the dorsum sellae2(Velayos & Santa na, 2004). The growth of the violence rates in Brazil, ma de considerable the use of fire guns (60%) in homicides that took place in the 1990 decade, reaching 70% in the year 200; in São Paulo, only 10% of the homicides were committed with another instrument but a fire gun in the same pe- riod. In Rio de Janeiro and Recife the proportion of homicides by fire guns was superior to 80% in 19913 (Peres & Santos, 2005). The present work reports a case that showed the importance of the forensic dentist in the forensic institutes through the identification of the retention spot for a projectile fired in a fatal victim in the Forensic Department of Vitória-ES.