title: Finite element analysis of stress distribution in ceramic crowns fabricated with different tooth preparation designs.
abstract: BACKGROUND
  Information about the effect of occlusal preparation designs on the stress distribution in different ceramic crowns and the prepared tooth is limited.
  
  
  OBJECTIVE
  The purpose of this study was to investigate the effects of anatomic and nonanatomic occlusal preparation designs on the stress distribution in ceramic crowns, teeth, and bone.
  
  
  METHODS
  Finite element analysis was performed on models of a mandibular second premolar. A load of 400 N was applied to the models to test ceramic materials (In-Ceram, Empress Esthetic) and occlusal preparation (anatomic, nonanatomic) designs.
  
  
  RESULTS
  The lowest stress value occurred in the core material in the Empress Esthetic model prepared with the nonanatomic occlusal preparation design. In all groups, higher stress values were found to be concentrated in the lingual half of the dentin. Lower stress values were located near the apex of the pulp tissue and bony tissue that surround the root apex.
  
  
  CONCLUSIONS
  Differences in preparation designs did not result in differences in the distribution or amount of stress in pulp, dentin, or bone. The use of different ceramic materials resulted in no differences in the amount or distribution of stress in pulp and bone. The use of a crown with a high elastic modulus led to increases in stress values in the restoration and the dentin margin, and decreases in stress values in the occlusal surface of the dentin. The nonanatomic design can be recommended as a favorable preparation design for Empress Esthetic ceramic.
authors.affiliation: Assistant Professor, School of Health Service, Dental Prosthetics Technology, Hacettepe University, Ankara, Turkey. Electronic address: poyar73@gmail.com.
authors.forename: Perihan
authors.initials: P
authors.lastname: Oyar
authors.affiliation: Professor, Department of Prosthodontics, University of Near East, Faculty of Dentistry, Cyprus, Turkey.
authors.forename: Mutahhar
authors.initials: M
authors.lastname: Ulusoy
authors.affiliation: Professor, Department of Prosthodontics, Gazi University, Faculty of Dentistry, Ankara, Turkey.
authors.forename: Gürcan
authors.initials: G
authors.lastname: Eskitaşçıoğlu
mesh_terms: D000537:Aluminum Oxide / Q000737:chemistry; D000538:Aluminum Silicates / Q000737:chemistry; D000539:Alveolar Process / Q000033:anatomy & histology; D001641:Bicuspid / Q000033:anatomy & histology; D002516:Ceramics / Q000737:chemistry*; D003442:Crowns; D003764:Dental Materials / Q000737:chemistry*; D003776:Dental Porcelain / Q000737:chemistry; D003782:Dental Pulp / Q000033:anatomy & histology; D003804:Dentin / Q000033:anatomy & histology; D055119:Elastic Modulus; D020342:Finite Element Analysis; D006801:Humans; D008334:Mandible; D013314:Stress, Mechanical; D019227:Tooth Apex / Q000033:anatomy & histology; D019231:Tooth Preparation, Prosthodontic / Q000379:methods*
chemical_list: D000538:Aluminum Silicates; D003764:Dental Materials; C075815:IPS-Empress ceramic; D003776:Dental Porcelain; C070870:In-Ceram; D000537:Aluminum Oxide