title: Numerical modeling of the fracture process in a three-unit all-ceramic fixed partial denture.
abstract: OBJECTIVE
  The main objectives were to examine the fracture mechanism and process of a ceramic fixed partial denture (FPD) framework under simulated mechanical loading using a recently developed numerical modeling code, the R-T(2D) code, and also to evaluate the suitability of R-T(2D) code as a tool for this purpose.
  
  
  METHODS
  Using the recently developed R-T(2D) code the fracture mechanism and process of a 3U yttria-tetragonal zirconia polycrystal ceramic (Y-TZP) FPD framework was simulated under static loading. In addition, the fracture pattern obtained using the numerical simulation was compared with the fracture pattern obtained in a previous laboratory test.
  
  
  RESULTS
  The result revealed that the framework fracture pattern obtained using the numerical simulation agreed with that observed in a previous laboratory test. Quasi-photoelastic stress fringe pattern and acoustic emission showed that the fracture mechanism was tensile failure and that the crack started at the lower boundary of the framework. The fracture process could be followed both in step-by-step and step-in-step.
  
  
  CONCLUSIONS
  Based on the findings in the current study, the R-T(2D) code seems suitable for use as a complement to other tests and clinical observations in studying stress distribution, fracture mechanism and fracture processes in ceramic FPD frameworks.
authors.affiliation: Dental Materials Science, Department of Odontology, Faculty of Medicine, Umeå University, Umeå, Sweden. wen.kou@odont.umu.se
authors.forename: Wen
authors.initials: W
authors.lastname: Kou
authors.forename: Shaoquan
authors.initials: S
authors.lastname: Kou
authors.forename: Hongyuan
authors.initials: H
authors.lastname: Liu
authors.forename: Göran
authors.initials: G
authors.lastname: Sjögren
mesh_terms: D000162:Acoustics; D001718:Birefringence; D019245:Compressive Strength; D003776:Dental Porcelain; D019232:Dental Restoration Failure; D003799:Dental Stress Analysis / Q000379:methods*; D003830:Denture, Partial, Fixed; D004548:Elasticity; D019544:Equipment Failure Analysis / Q000379:methods; D008422:Materials Testing / Q000379:methods; D008962:Models, Theoretical; D009716:Numerical Analysis, Computer-Assisted; D013718:Tensile Strength; D015019:Yttrium; D015040:Zirconium
chemical_list: C499362:yttria stabilized tetragonal zirconia; D003776:Dental Porcelain; D015019:Yttrium; D015040:Zirconium