title: Influence of customized composite resin fibreglass posts on the mechanics of restored treated teeth.
abstract: OBJECTIVE
  To evaluate the mechanical behaviour of the dentine/cement/post interface of a maxillary central incisor using the finite element method and to compare the stresses exerted using conventional or customized post cementation techniques.
  
  
  METHODS
  Four models of a maxillary central incisor were created using fibreglass posts cemented with several techniques: FGP1, a 1-mm-diameter conventionally cemented post; CFGP1, a 1-mm-diameter customized composite resin post; FGP2, a 2-mm-diameter conventionally cemented post; CFGP2, a 2-mm-diameter customized composite resin post. A distributed load of 1N was applied to the lingual aspect of the tooth at 45° to its long axis. Additionally, polymerization shrinkage of 1% was simulated for the resin cement. The surface of the periodontal ligament was fixed in the three axes (X =Y = Z = 0). The maximum principal stress (σ(max) ), minimum principal stress (σ(min)), equivalent von Mises stress (σ(vM) ) and shear stress (σ(shear)) were calculated for the dentine/cement/post interface using finite element software.
  
  
  RESULTS
  The peak of σ(max) for the cement layer occurred first in CFGP1 (1.77 MPa), followed by CFGP2 (0.99), FGP2 (0.44) and FGP1 (0.2). The shrinkage stress (σ(vM) ) of the cement layer occurred as follows: FGP1 (35 MPa), FGP2 (34), CFGP1 (30.7) and CFGP2 (30.1).
  
  
  CONCLUSIONS
  Under incisal loading, the cement layer of customized posts had higher stress concentrations. The conventional posts showed higher stress because of polymerization shrinkage.
authors: Department of Dental Materials and Prosthodontics, Faculty of Dentistry of Araçatuba - UNESP, Sao Paulo State University, Sao Paulo Federal Institute of Parana - IFPR, Parana, Brazil. rodolfoanchieta@hotmail.com
authors: R B
authors: RB
authors: Anchieta
authors: E P
authors: EP
authors: Rocha
authors: E O
authors: EO
authors: Almeida
authors: A C
authors: AC
authors: Freitas
authors: M
authors: M
authors: Martin
authors: A P
authors: AP
authors: Martini
authors: C M
authors: CM
authors: Archangelo
authors: C-C
authors: CC
authors: Ko
mesh_terms: D001696:Biomechanical Phenomena; D002484:Cementation / Q000379:methods; D003188:Composite Resins / Q000737:chemistry*; D003198:Computer Simulation; D003764:Dental Materials / Q000737:chemistry*; D017267:Dental Prosthesis Design; D003786:Dental Pulp Cavity / Q000648:ultrastructure*; D003804:Dentin / Q000648:ultrastructure*; D055119:Elastic Modulus; D020342:Finite Element Analysis; D005898:Glass / Q000737:chemistry*; D006801:Humans; D007091:Image Processing, Computer-Assisted / Q000379:methods; D021621:Imaging, Three-Dimensional / Q000379:methods; D007180:Incisor / Q000648:ultrastructure*; D008422:Materials Testing; D008954:Models, Biological; D010513:Periodontal Ligament / Q000502:physiology; D058105:Polymerization; D011176:Post and Core Technique / Q000295:instrumentation*; D019279:Resin Cements / Q000737:chemistry*; D033081:Shear Strength; D013314:Stress, Mechanical; D013499:Surface Properties; D055114:X-Ray Microtomography / Q000379:methods
chemical_list: D003188:Composite Resins; D003764:Dental Materials; D019279:Resin Cements; C009753:fiberglass