title: Finite-element analysis of 3 situations of trauma in the human edentulous mandible.
abstract: OBJECTIVE
  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).
  
  
  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.
authors.affiliation: Professor, Brazilian Dental Association, Pará Section, Belém, PA, Brazil.
authors.forename: Leonardo Soriano de Mello
authors.initials: LS
authors.lastname: Santos
authors.affiliation: Professor, Department of Morphology, Anatomy Area, Piracicaba Dental School, State University of Campinas, Piracicaba, SP, Brazil. Electronic address: rossiac@fop.unicamp.br.
authors.forename: Ana Cláudia
authors.initials: AC
authors.lastname: Rossi
authors.affiliation: PhD Student, Department of Morphology, Anatomy Area, Piracicaba Dental School, State University of Campinas, Piracicaba, SP, Brazil.
authors.forename: Alexandre Rodrigues
authors.initials: AR
authors.lastname: Freire
authors.affiliation: PhD Student, Department of Morphology, Anatomy Area, Piracicaba Dental School, State University of Campinas, Piracicaba, SP, Brazil.
authors.forename: Rodrigo Ivo
authors.initials: RI
authors.lastname: Matoso
authors.affiliation: Associate Professor, Department of Morphology, Anatomy Area, Piracicaba Dental School, State University of Campinas, Piracicaba, SP, Brazil.
authors.forename: Paulo Henrique Ferreira
authors.initials: PH
authors.lastname: Caria
authors.affiliation: Professor, Department of Morphology, Anatomy Area, Piracicaba Dental School, State University of Campinas, Piracicaba, SP, Brazil.
authors.forename: Felippe Bevilacqua
authors.initials: FB
authors.lastname: Prado
mesh_terms: D000368:Aged; D001696:Biomechanical Phenomena; D003198:Computer Simulation; D017076:Computer-Aided Design; D055119:Elastic Modulus; D020342:Finite Element Analysis; D006801:Humans; D021621:Imaging, Three-Dimensional / Q000379:methods; D007575:Jaw, Edentulous / Q000503:physiopathology*; D008334:Mandible / Q000503:physiopathology*; D008335:Mandibular Condyle / Q000503:physiopathology; D008337:Mandibular Fractures / Q000503:physiopathology*; D008410:Masticatory Muscles / Q000503:physiopathology; D008953:Models, Anatomic; D008954:Models, Biological; D013314:Stress, Mechanical; D014057:Tomography, X-Ray Computed / Q000379:methods