title: Finite element analysis of maxillary bone stress caused by Aramany Class IV obturator prostheses.
abstract: BACKGROUND
  The retention of an Aramany Class IV removable partial dental prosthesis can be compromised by a lack of support. The biomechanics of this obturator prosthesis result in an unusual stress distribution on the residual maxillary bone.
  
  
  OBJECTIVE
  This study evaluated the biomechanics of an Aramany Class IV obturator prosthesis with finite element analysis and a digital 3-dimensional (3-D) model developed from a computed tomography scan; bone stress was evaluated according to the load placed on the prosthesis.
  
  
  METHODS
  A 3-D model of an Aramany Class IV maxillary resection and prosthesis was constructed. This model was used to develop a finite element mesh. A 120 N load was applied to the occlusal and incisal platforms corresponding to the prosthetic teeth. Qualitative analysis was based on the scale of maximum principal stress; values obtained through quantitative analysis were expressed in MPa.
  
  
  RESULTS
  Under posterior load, tensile and compressive stresses were observed; the tensile stress was greater than the compressive stress, regardless of the bone region, and the greatest compressive stress was observed on the anterior palate near the midline. Under an anterior load, tensile stress was observed in all of the evaluated bone regions; the tensile stress was greater than the compressive stress, regardless of the bone region.
  
  
  CONCLUSIONS
  The Aramany Class IV obturator prosthesis tended to rotate toward the surgical resection when subjected to posterior or anterior loads. The amount of tensile and compressive stress caused by the Aramany Class IV obturator prosthesis did not exceed the physiological limits of the maxillary bone tissue. (J Prosthet Dent 2012;107:336-342).
authors.affiliation: Department of Maxillofacial Surgery, Prosthesis and Traumatology, School of Dentistry, University of São Paulo, São Paulo, Brazil.
authors.forename: Elcio Ricardo
authors.initials: ER
authors.lastname: Miyashita
authors.forename: Beatriz Silva Câmara
authors.initials: BS
authors.lastname: Mattos
authors.forename: Pedro Yoshito
authors.initials: PY
authors.lastname: Noritomi
authors.forename: Hamilton
authors.initials: H
authors.lastname: Navarro
mesh_terms: D000328:Adult; D001732:Bite Force; D019245:Compressive Strength; D003198:Computer Simulation; D017267:Dental Prosthesis Design; D003799:Dental Stress Analysis / Q000379:methods; D003830:Denture, Partial, Fixed; D004548:Elasticity; D020342:Finite Element Analysis; D006801:Humans; D021621:Imaging, Three-Dimensional; D008297:Male; D008437:Maxilla / Q000502:physiology*; D003765:Models, Dental; D010158:Palatal Obturators; D013718:Tensile Strength