title: [Influence of attachment type on stress distribution of implant-supported removable partial dentures].
abstract: OBJECTIVE
  To compare influences of different retention attachments on stress among supporting structures.
  
  
  METHODS
  By 3-dimensional laser scanner and reverse engineering computer aided design (CAD) software, a basic partially edentulous digital model with mandibular premolar and molar missing was established. Implant attachment and removable partial dentures (RPD) were added into the basic model to build three kinds of models: RPD only, RPD + implant + Locator attachment, and RPD + implant + Magfit attachment. Vertical and inclined loads were put on artificial teeth unilaterally. By means of 3-dimensional finite element analysis, the stress distribution and displacement of the main supportive structures were compared.
  
  
  RESULTS
  A complete 3-dimensional finite element model was established, which contained tooth structure, and periodontal structures. The displacement of the denture was smaller in Locator (9.38 μm vertically, 45.48 μm obliquely) and Magfit models (9.54 μm vertically, 39.45 μm obliquely) compared with non-implant RPD model (95.27 μm vertically, 155.70 μm obliquely). Compared with the two different attachments, cortical bone stress value was higher in Locator model (Locator model 10.850 MPa vertically, 43.760 MPa obliquely; Magfit model 7.100 MPa vertically, 19.260 MPa obliquely).The stress value of abutment periodontal ligamentin Magfit model (0.420 MPa vertically) was lower than that in Locator model (0.520 MPa vertically).
  
  
  CONCLUSIONS
  The existence of implant could reduce maximum von Mises value of each supportive structure when Kennedy I partially edentulous mandible was restored. Comparing the structure of Magfit and Locator attachment, the contact of Magfit attachment was rigid, while Locator was resilient. Locator attachment could improve stability of the denture dramatically. Locator had stronger effect on defending horizontal movement of the denture.
authors: Department of Prosthodontics, Peking University School and Hospital of Stomatology, Beijing 100081, China; First Clinical Division, Peking Univesity School and Hospital of Stomatology, Beijing 100034, China.
authors: Xue
authors: X
authors: Yang
authors: Department of Bio-medical Engineering, Peking University College of Engineering, Beijing 100871, China.
authors: Qi-guo
authors: QG
authors: Rong
authors: Department of Prosthodontics, Peking University School and Hospital of Stomatology, Beijing 100081, China.
authors: Ya-dong
authors: YD
authors: Yang
mesh_terms: D017076:Computer-Aided Design; D003799:Dental Stress Analysis; D003832:Denture, Partial, Removable; D020342:Finite Element Analysis; D006801:Humans