title: Finite element analysis of the influence of geometry and design of zirconia crowns on stress distribution.
abstract: OBJECTIVE
  To evaluate the influence of the geometry and design of prosthetic crown preparations on stress distribution in compression tests, using finite element analysis (FEA).
  
  
  METHODS
  Six combinations of 3D drawings of all-ceramic crowns (yttria-stabilized zirconia framework and porcelain veneer) were evaluated: F, flat preparation and simplified crown; FC, flat preparation and crown with contact point; FCM, flat preparation and modified crown; A, anatomical preparation and simplified anatomical crown framework; AC, anatomical preparation and crown with contact point; and ACM, anatomical preparation and modified crown. Bonded contact types at all interfaces with the mesh were assigned, and the material properties used were according to the literature. A 200 N vertical load was applied at the center of each model. The maximum principal stresses were quantitatively and qualitatively analyzed.
  
  
  RESULTS
  The highest values of tensile stress were observed at the interface between the ceramics in the region under the load application for the simplified models (F and A). Reductions in stress values were observed for the model with the anatomical preparation and modified infrastructure (ACM). The stress distribution in the flat models was similar to that of their respective anatomical models.
  
  
  CONCLUSIONS
  The modified design of the zirconia coping reduces the stress concentration at the interface with the veneer ceramic, and the simplified preparation can exert a stress distribution similar to that of the anatomical preparation at and near the load point, when load is applied to the center of the crown.
authors: Department of Dental Materials and Prosthodontics, Institute of Science and Technology, UNESP - Univ Estadual Paulista, São José dos Campos, Brazil.
authors: Lilian Costa
authors: LC
authors: Anami
authors: Julia Magalhaes da Costa
authors: JM
authors: Lima
authors: Pedro Henrique
authors: PH
authors: Corazza
authors: Eron Toshio Colauto
authors: ET
authors: Yamamoto
authors: Marco Antonio
authors: MA
authors: Bottino
authors: Alexandre Luiz Souto
authors: AL
authors: Borges
mesh_terms: D003442:Crowns; D003799:Dental Stress Analysis; D020342:Finite Element Analysis; D008422:Materials Testing; D013314:Stress, Mechanical; D015040:Zirconium / Q000737:chemistry*
chemical_list: D015040:Zirconium; C028541:zirconium oxide
keywords: Preparation geometry; bilaminate system; restoration design; zirconia