title: Effects of post core materials on stress distribution in the restoration of mandibular second premolars: a finite element analysis.
abstract: BACKGROUND
  Previous studies have not resolved the question as to which post and core combination optimizes the stress distribution within the post restoration and tooth.
  
  
  OBJECTIVE
  The purpose of this study was to determine which post and core combination provides the most favorable stress distribution upon loading.
  
  
  METHODS
  Three-dimensional models of teeth were created with the Ansys program to simulate different materials used for post and cores (Ti, NiCr, AuPd, zirconia, zirconia post/composite resin core, glass fiber post/composite resin core, and carbon fiber post/composite resin core) and metal ceramic crowns (nickel chromium alloy [Group NiCr] and gold palladium alloy [Group AuPd]). A force of 400 N was applied to the occlusal surface, and von Mises equivalent stress values were calculated.
  
  
  RESULTS
  Carbon fiber post/composite resin core/metal ceramic crowns with NiCr alloy core had the highest stress values in the weakened root, tooth/post interface, and post. NiCr post/NiCr core/metal ceramic crowns with NiCr alloy core had the lowest stress values in the weakened root and post. The zirconia post and core had the lowest stress value in the tooth/post interface.
  
  
  CONCLUSIONS
  A post material with a high elastic modulus led to lower stress in the weakened root (approximately 6%) and tooth/post interface (approximately 12%) and to higher stress in the post (approximately 5 times). A composite resin core led to higher stress in the weakened root (approximately 11% to 17%) and lower deformation in the tooth/post interface (approximately 17.5%) and post materials (approximately 24%). Group AuPd resulted in lower stress in the root and high stress in the post (approximately 4.5% to 7%) and affected the amount of deformation in posts with a composite resin core.
authors.affiliation: Assistant Profesor, Department of Construction, Gazi University Technology Faculty, Ankara, Turkey.
authors.forename: Gökhan
authors.initials: G
authors.lastname: Durmuş
authors.affiliation: Assistant Professor, Dental Prosthetics Technology, School of Health Services, Hacettepe University, Ankara, Turkey. Electronic address: poyar73@gmail.com.
authors.forename: Perihan
authors.initials: P
authors.lastname: Oyar
mesh_terms: D001641:Bicuspid / Q000502:physiology*; D002244:Carbon / Q000737:chemistry; D000077482:Carbon Fiber; D002516:Ceramics / Q000737:chemistry; D002858:Chromium Alloys / Q000737:chemistry; D003188:Composite Resins / Q000737:chemistry; D003198:Computer Simulation; D003722:Dental Alloys / Q000737:chemistry; D003764:Dental Materials / Q000737:chemistry*; D003786:Dental Pulp Cavity / Q000502:physiology; D055119:Elastic Modulus; D020342:Finite Element Analysis; D005898:Glass / Q000737:chemistry; D006047:Gold Alloys / Q000737:chemistry; D006801:Humans; D021621:Imaging, Three-Dimensional / Q000379:methods; D008334:Mandible / Q000502:physiology; D008422:Materials Testing; D016876:Metal Ceramic Alloys / Q000737:chemistry; D008954:Models, Biological; D010165:Palladium / Q000737:chemistry; D011176:Post and Core Technique; D013314:Stress, Mechanical; D014025:Titanium / Q000737:chemistry; D014092:Tooth Root / Q000502:physiology; D019553:Tooth, Nonvital / Q000503:physiopathology; D015040:Zirconium / Q000737:chemistry
chemical_list: D000077482:Carbon Fiber; D002858:Chromium Alloys; D003188:Composite Resins; D003722:Dental Alloys; D003764:Dental Materials; D006047:Gold Alloys; D016876:Metal Ceramic Alloys; C009753:fiberglass; D010165:Palladium; D002244:Carbon; D015040:Zirconium; D014025:Titanium; C028541:zirconium oxide