title: [Three-dimensional finite element analysis on half of the structure defect with post core and all-ceramic crown restoration of mandibular first molar].
abstract: OBJECTIVE
  To make a mechanical analysis on three-dimensional finite element models of the mandibular first molar defect restored with post core and all-ceramic crown, and to provide a guideline for planning restoration for such kind of tooth structure defect.
  
  
  METHODS
  Cone-beam CT based three dimensional finite element models of post and core restored first mandibular molars were established, with 6 different ferrule designs (the ferrule with only 180 axial wall on different locations). The von Misses criterion was applied for comparing the maximum von Misses stress value of dentin and stress concentration areas in six models which restored with fiber post or cast NiGr alloy post core or Au alloy post core under the maximum, vertical, inclined and horizontal direct loads.
  
  
  RESULTS
  The restoration effects in six models were compared, and the maximum von Misses stress concentration areas were not obviously different. The maximum von Misses stress value of NiCr alloy post core and crown was 62.81 MPa. Under horizontal load, the maximum von Misses stress value of dentin increased remarkably.
  
  
  CONCLUSIONS
  The location of residual dentin has little influence on the stress distribution, when restored by post core and crown. Au alloy post core and crown or fiber post core and crown are superior to NiCr alloy post core and crown.
authors.affiliation: Department of Stomatology, Affiliated Hospital of Jining Medical University, Jining Shandong 272100, China.
authors.forename: Tao
authors.initials: T
authors.lastname: Liu
authors.forename: Haixia
authors.initials: H
authors.lastname: Geng
authors.forename: Qiguo
authors.initials: Q
authors.lastname: Rong
authors.affiliation: Department of Prosthodontics, Peking University School and Hospital of Stomatology, Beijing 100081, China; Email: jianzhang_l@163.com.
authors.forename: Jianzhang
authors.initials: J
authors.lastname: Liu
mesh_terms: D002858:Chromium Alloys; D054893:Cone-Beam Computed Tomography; D003442:Crowns; D003776:Dental Porcelain; D003793:Dental Restoration, Permanent; D003799:Dental Stress Analysis; D003804:Dentin / Q000502:physiology*; D020342:Finite Element Analysis; D008963:Molar; D011176:Post and Core Technique
chemical_list: D002858:Chromium Alloys; D003776:Dental Porcelain