title: Stress analysis of effects of nonrigid connectors on fixed partial dentures with pier abutments.
abstract: BACKGROUND
  In some patients, the pattern of missing teeth may require the use of a fixed partial denture (FPD) with an intermediate pier abutment. Information is needed regarding the biomechanical behavior and the position of a nonrigid connector for this treatment option.
  
  
  OBJECTIVE
  The purpose of this study was to evaluate, by means of finite element method (FEM), the effects of rigid and nonrigid design types on stress distribution for 5-unit FPDs with pier abutments.
  
  
  METHODS
  A 3-dimensional cross-section FEM model (SAP 2000) simulating a 5-unit metal ceramic FPD with a pier abutment with rigid or nonrigid designs (connector location at the mesial region of the second molar, at the distal region of the second premolar, at the mesial region of the second premolar, and at the distal region of the canine) was developed. In the model, the canine, second premolar, and second molar served as abutments. A supporting periodontal ligament and alveolar bone (cortical and trabecular) were modeled. A 50-N static vertical occlusal load was applied on the cusp of each abutment to calculate the stress distributions. Three different types of load were evaluated: loading of all cusps to simulate maximum centric occlusion contacts, loading of the canine to simulate a single anterior contact, and loading of the second molar to simulate a posterior contact.
  
  
  RESULTS
  The analysis of the von Mises stress values revealed that maximum stress concentrations were located at the load areas for all models. Also, for all models, the highest stress values were located at connectors and cervical regions of abutment teeth, especially at the pier abutment.
  
  
  CONCLUSIONS
  The area of maximum stress concentration at the pier abutment was decreased by the use of a nonrigid connector at the distal region of the second premolar.
authors.affiliation: Gulhane Military Medicine Academy, Istanbul, Turkey.
authors.forename: Selcuk
authors.initials: S
authors.lastname: Oruc
authors.forename: Oguz
authors.initials: O
authors.lastname: Eraslan
authors.forename: H Alper
authors.initials: HA
authors.lastname: Tukay
authors.forename: Arzu
authors.initials: A
authors.lastname: Atay
mesh_terms: D000539:Alveolar Process / Q000502:physiology; D001641:Bicuspid / Q000502:physiology; D001696:Biomechanical Phenomena; D001732:Bite Force; D003198:Computer Simulation; D003481:Cuspid / Q000502:physiology; D000044:Dental Abutments; D003764:Dental Materials / Q000737:chemistry*; D003768:Dental Occlusion, Centric; D003779:Denture Design; D003830:Denture, Partial, Fixed; D004548:Elasticity; D020342:Finite Element Analysis; D006801:Humans; D021621:Imaging, Three-Dimensional / Q000379:methods; D008422:Materials Testing; D008954:Models, Biological; D008963:Molar / Q000502:physiology; D010513:Periodontal Ligament / Q000502:physiology; D013314:Stress, Mechanical; D019227:Tooth Apex / Q000502:physiology; D014092:Tooth Root / Q000502:physiology
chemical_list: D003764:Dental Materials