title: Finite element analysis of stress-breaking attachments on maxillary implant-retained overdentures.
abstract: OBJECTIVE
  The purpose of this study was to examine the effect of stress-breaking attachments at the connections between maxillary palateless overdentures and implants.
  
  
  METHODS
  Three-dimensional finite element models were used to reproduce an edentulous human maxilla with an implant-retained overdenture. Two-implant models (in the canine tooth positions on both sides) and four-implant models (in the canine and second premolar tooth positions on both sides) were examined. Stress-breaking material connecting the implants and denture was included around each abutment. Axial loads of 100 N were applied to the occlusal surface at the left first molar tooth positions. In each model, the influence of the stress-breaking attachments was compared by changing the elastic modulus from 1 to 3,000 MPa and the thickness of the stress-breaking material from 1 to 3 mm. Maximum stress at the implant-bone interface and stress at the cortical bone surface just under the loading point were calculated.
  
  
  RESULTS
  In all models, maximum stress at the implant-bone interface with implants located in the canine tooth position was generated at the peri-implant bone on the loading side. As the elastic modulus of the stress-breaking materials increased, the stress increased at the implant-bone interface and decreased at the cortical bone surface. Moreover, stress at the implant-bone interface with 3-mm-thick stress-breaking material was smaller than that with 1-mm-thick material.
  
  
  CONCLUSIONS
  Within the limitations of this experiment, stress generated at the implant-bone interface could be controlled by altering the elastic modulus and thickness of the stress-breaking materials.
authors: Complete Denture Prosthodontics, Graduate School, Tokyo Medical and Dental University, Tokyo, Japan. f.tanino.ore@tmd.ac.jp
authors: Fuminori
authors: F
authors: Tanino
authors: Iwao
authors: I
authors: Hayakawa
authors: Shigezo
authors: S
authors: Hirano
authors: Shunsuke
authors: S
authors: Minakuchi
mesh_terms: D001641:Bicuspid; D001732:Bite Force; D003198:Computer Simulation; D003481:Cuspid; D000044:Dental Abutments; D015921:Dental Implants; D003764:Dental Materials / Q000737:chemistry; D019094:Dental Prosthesis, Implant-Supported; D003779:Denture Design; D003822:Denture Liners; D003781:Denture Retention; D003827:Denture, Complete, Upper; D003828:Denture, Overlay; D004548:Elasticity; D020342:Finite Element Analysis; D006801:Humans; D021621:Imaging, Three-Dimensional; D008422:Materials Testing; D008437:Maxilla / Q000502:physiology; D008954:Models, Biological; D016348:Osseointegration / Q000502:physiology; D013314:Stress, Mechanical; D013499:Surface Properties
chemical_list: D015921:Dental Implants; D003764:Dental Materials