title: Finite element analysis of an implant-assisted removable partial denture.
abstract: OBJECTIVE
  This study analyzes the effects of loading a Kennedy class I implant-assisted removable partial denture (IARPD) using finite element analysis (FEA). Standard RPDs are not originally designed to accommodate a posterior implant load point. The null hypothesis is that the introduction of posteriorly placed implants into an RPD has no effect on the load distribution.
  
  
  METHODS
  A Faro Arm scan was used to extract the geometrical data of a human partially edentulous mandible. A standard plus regular neck (4.8 × 12 mm) Straumann® implant and titanium matrix, tooth roots, and periodontal ligaments were modeled using a combination of reverse engineering in Rapidform XOR2 and solid modeling in Solidworks 2008 FEA program. The model incorporated an RPD and was loaded with a bilateral force of 120 N. ANSYS Workbench 11.0 was used to analyze deformation in the IARPD and elastic strain in the metal framework.
  
  
  RESULTS
  FEA identified that the metal framework developed high strain patterns on the major and minor connectors, and the acrylic was subjected to deformation, which could lead to acrylic fractures. The ideal position of the neutral axis was calculated to be 0.75 mm above the ridge.
  
  
  CONCLUSIONS
  A potentially destructive mismatch of strain distribution was identified between the acrylic and metal framework, which could be a factor in the failure of the acrylic. The metal framework showed high strain patterns on the major and minor connectors around the teeth, while the implant components transferred the load directly to the acrylic.
authors.affiliation: Private practice, Auckland, New Zealand.
authors.forename: Reza
authors.initials: R
authors.lastname: Shahmiri
authors.affiliation: Department of Oral Rehabilitation, University of Otago, Dunedin, New Zealand.
authors.forename: John M
authors.initials: JM
authors.lastname: Aarts
authors.affiliation: Private practice, Auckland, New Zealand.
authors.forename: Vincent
authors.initials: V
authors.lastname: Bennani
authors.affiliation: Department of Oral Rehabilitation, University of Otago, Dunedin, New Zealand.
authors.forename: Momen A
authors.initials: MA
authors.lastname: Atieh
authors.affiliation: Department of Oral Rehabilitation, University of Otago, Dunedin, New Zealand.
authors.forename: Michael V
authors.initials: MV
authors.lastname: Swain
mesh_terms: D000180:Acrylic Resins / Q000737:chemistry; D000465:Algorithms; D001696:Biomechanical Phenomena; D001732:Bite Force; D003198:Computer Simulation; D003722:Dental Alloys / Q000737:chemistry; D015921:Dental Implants; D003764:Dental Materials / Q000737:chemistry; D019094:Dental Prosthesis, Implant-Supported; D003819:Denture Bases; D003779:Denture Design; D003832:Denture, Partial, Removable; D055119:Elastic Modulus; D020342:Finite Element Analysis; D006801:Humans; D007576:Jaw, Edentulous, Partially / Q000145:classification; D008334:Mandible / Q000473:pathology; D008422:Materials Testing; D008954:Models, Biological; D013314:Stress, Mechanical
chemical_list: D000180:Acrylic Resins; D003722:Dental Alloys; D015921:Dental Implants; D003764:Dental Materials
keywords: Implant-assisted removable partial denture; dental implant; finite element analysis; removable partial denture