title: The effects of post-core and crown material and luting agents on stress distribution in tooth restorations.
abstract: BACKGROUND
  Cement microfracture, post-and-core dislodgement, and tooth fracture are related to the mechanical properties and deformation of restorations.
  
  
  OBJECTIVE
  The purpose of this study was to determine which combinations of post-and-core cements provide the most favorable stress distribution upon loading.
  
  
  METHODS
  Three-dimensional models of teeth were created with the ANSYS program to simulate the different materials used for metal ceramic crowns (nickel-chromium, gold-palladium), posts and cores (Ti, Ni-Cr, Au-Pd), and cement (glass ionomer, composite resin, zinc phosphate, polycarboxylate, Panavia). Models were divided into 2 groups according to the alloys used in the crown restorations. A simulated masticatory force of 400 N was applied to the occlusal surface at a 45-degree inclination in the linguolabial direction to the long axis of the tooth, and von Mises equivalent stress values were calculated.
  
  
  RESULTS
  The Ni-Cr metal ceramic crown/Au-Pd post-and-core/glass ionomer cement had the highest residual root von Mises equivalent stress value, whereas the Ni-Cr metal ceramic crown/Ni-Cr post-and-core/glass ionomer cement had the highest post stress value and the Ni-Cr metal ceramic crown/Au-Pd post-and-core/zinc phosphate cement had the highest cement stress value. For each post-and-core alloy, the stress values in the post and core were higher with Au-Pd metal ceramic crowns than with Ni-Cr metal ceramic crowns. The post-and-core material affected the amount of deformation.
  
  
  CONCLUSIONS
  The use of a post-and-core material with a lower elastic modulus and a cement with a higher elastic modulus led to a reduction in deformation in the residual root, cement, and post and core, and a reduction in stress in the post and core. The Ni-Cr metal ceramic crown/Au-Pd post-and-core/zinc phosphate cement or Panavia may therefore be favorable for post-and-core restorations.
authors.affiliation: Assistant Professor, Dental Prosthetics Technology Programme, School of Health Services, Hacettepe University, Ankara, Turkey. Electronic address: poyar73@gmail.com.
authors.forename: Perihan
authors.initials: P
authors.lastname: Oyar
mesh_terms: D001732:Bite Force; D002858:Chromium Alloys / Q000737:chemistry; D003188:Composite Resins / Q000737:chemistry; D003738:Dental Cements / Q000737:chemistry*; D003764:Dental Materials / Q000737:chemistry*; D003804:Dentin / Q000648:ultrastructure*; D055119:Elastic Modulus; D020342:Finite Element Analysis; D005899:Glass Ionomer Cements / Q000737:chemistry; D006047:Gold Alloys / Q000737:chemistry; D006801:Humans; D021621:Imaging, Three-Dimensional / Q000379:methods; D008422:Materials Testing; D016876:Metal Ceramic Alloys / Q000737:chemistry; D008689:Methacrylates / Q000737:chemistry; D010165:Palladium / Q000737:chemistry; D011076:Polycarboxylate Cement / Q000737:chemistry; D011176:Post and Core Technique; D019279:Resin Cements / Q000737:chemistry; D013314:Stress, Mechanical; D014025:Titanium / Q000737:chemistry; D014092:Tooth Root / Q000648:ultrastructure*; D015036:Zinc Phosphate Cement / Q000737:chemistry
chemical_list: D002858:Chromium Alloys; D003188:Composite Resins; D003738:Dental Cements; D003764:Dental Materials; D005899:Glass Ionomer Cements; D006047:Gold Alloys; D016876:Metal Ceramic Alloys; D008689:Methacrylates; D011076:Polycarboxylate Cement; D019279:Resin Cements; C091744:Panavia TC; D010165:Palladium; D015036:Zinc Phosphate Cement; D014025:Titanium