title: Three-dimensional stress analysis of tooth/lmplant-retained long-span fixed dentures.
abstract: OBJECTIVE
  The aim was to assess the influence of connection of the canine teeth to implant-retained long-span fixed dentures on stress in mandibular bone using finite element analysis.
  
  
  METHODS
  Each 3-dimensional model included bone, 6 implants, both natural canines, and superstructures. Each model simulated 1 of 4 prosthetic designs: a tooth/implant-retained 1-piece superstructure (One-piece), 3-piece superstructures with an anterior and 2 posterior segments with unconnected teeth (UnConnect), 3-piece superstructures with the teeth connected to the posterior segments (PostConnect), and 3-piece superstructures with the teeth connected to the anterior segment (AntConnect). A nonlinear elastic modulus was applied to the periodontal ligament (PDL). Maximum intercuspal (IP), canine-protected (CP), and group-function (GF) occlusions were simulated.
  
  
  RESULTS
  The maximum stresses in the peri-implant regions of the bone were lower for the One-piece than for the other superstructures. In PostConnect and AntConnect, the maximum stress in the PDL was lower than that in UnConnect, but the stress in the peri-implant bone was comparable in those 3 models. The stresses were lower in the GF model than in the CP model. The stress created in the peri-implant bone was insensitive to the modes of the teeth/implant connection in long-span fixed dentures.
  
  
  CONCLUSIONS
  Within the limitation of the mechanical analysis, it is suggested that the connection of the canine tooth to the implant-retained long-span superstructures is an acceptable option in partially edentulous patients.
authors.affiliation: Oral Implantology and Regenerative Dental Medicine, Department of Masticatory Function Rehabilitation, Division of Oral Health Sciences, Graduate School, Tokyo Medical and Dental University, Tokyo, Japan. maezawa.impl@tmd.ac.jp
authors.forename: Nariyuki
authors.initials: N
authors.lastname: Maezawa
authors.forename: Makoto
authors.initials: M
authors.lastname: Shiota
authors.forename: Shohei
authors.initials: S
authors.lastname: Kasugai
authors.forename: Noriyuki
authors.initials: N
authors.lastname: Wakabayashi
mesh_terms: D003198:Computer Simulation; D003481:Cuspid / Q000502:physiology*; D000044:Dental Abutments; D003724:Dental Arch / Q000502:physiology; D015921:Dental Implants; D003766:Dental Occlusion; D003779:Denture Design; D003781:Denture Retention; D003830:Denture, Partial, Fixed; D004548:Elasticity; D020342:Finite Element Analysis; D006801:Humans; D021621:Imaging, Three-Dimensional; D007576:Jaw, Edentulous, Partially / Q000503:physiopathology; D008334:Mandible / Q000502:physiology; D008954:Models, Biological; D010513:Periodontal Ligament / Q000502:physiology; D013314:Stress, Mechanical
chemical_list: D015921:Dental Implants