title: Finite Element Analysis of IPS Empress II Ceramic Bridge Reinforced by Zirconia Bar.
abstract: OBJECTIVE
  The aim of this study was to determine the effect of trenched zirconia bar on the von Mises stress distribution of IPS -Empress II core ceramics.
  
  
  METHODS
  The three-dimensional model including a three-unit bridge from the second premolar to the second molar was designed. The model was reinforced with zirconia bar (ZB), zirconia bar with vertical trench (VZB) and zirconia bar with horizontal trench (HZB) (cross sections of these bars were circular). The model without zirconia bar was designed as the control. The bridges were loaded by 200 N and 500 N on the occlusal surface at the middle of the pontic component and von Mises stresses were evaluated along a defined path.
  
  
  RESULTS
  IN THE CONNECTOR AREA, VON MISES STRESS IN MPA WERE APPROXIMATELY IDENTICAL IN THE SPECIMENS WITH ZB (AT MOLAR CONNECTOR (MC): 4.75 and at premolar connector (PC): 6.40) and without ZB (MC: 5.50, PC: 6.68), and considerable differences were not recognized. Whereas, Von-Mises stress (MPa) in the specimens with horizontal trenched Zirconia bar (HZB) (MC: 3.91, PC: 2.44) and Vertical trenched Zirconia bar (VZB) (MC: 2.53, PC: 2.56) was decreased considerably.
  
  
  CONCLUSIONS
  Embeded trenched zirconia bar could reinforce IPS-Empress II at the connector area which is a main failure region in all ceramic fixed partial dentures.
authors: Assistant Professor, Department of Dental Research Center and Operative Dentistry, Faculty of Dentistry, Tehran University of Medical Science, Iran.
authors: H
authors: H
authors: Kermanshah
authors: T
authors: T
authors: Bitaraf
authors: A
authors: A
authors: Geramy
keywords: Ceramics; Finite Element Analysis; Resin-Bonded Fixed Partial Denture; Zirconia