title: Bending properties of Ce-TZP/A nanocomposite clasps for removable partial dentures.
abstract: OBJECTIVE
  Ceria-stabilized zirconia/alumina nanocomposite (Ce-TZP/A) has excellent fracture toughness and bending strength that could be useful for partial denture framework application. The aim of this study was to investigate the effects of three-dimensional (3D) geometry on the bending and fatigue properties of a model simulation of Ce-TZP/A clasps.
  
  
  METHODS
  Half oval-shaped Ce-TZP/A rods were prepared in six 3D designs. Specimens were either of standard (width divided by thickness: 2.0/1.0 mm) or flat type (2.5/0.8 mm) cross-sectional areas with taper ratios of 1.0, 0.8, or 0.6. As a comparison, cobalt-chromium (Co-Cr) alloy rods of the same shape as the Ce-TZP/A standard shape rod were prepared. All specimens were subjected to the cantilever test and loaded until fracture. They were also cyclically loaded 106 times with various constant displacements, and the maximum displacement prior to fracture was determined for each specimen. Three-dimensional finite element analysis (3D FEA), simulating the cantilever test, was performed to determine the stress distribution during loading.
  
  
  RESULTS
  Specimens with the standard cross-sectional shape exhibited higher rigidity and higher fracture loads than the flat specimens by the cantilever test. In addition, lower taper ratios were consistently associated with larger displacements at fracture. Fatigue tests revealed that the maximum displacement prior to fracture of Ce-TZP/A specimens was comparable to that of Co-Cr alloy specimens. The 3D FEA showed that specimens with a taper ratio of 0.6 had the least stress concentration.
  
  
  CONCLUSIONS
  Ce-TZP/A clasp specimens with a standard cross-sectional shape and a 0.6 taper ratio exhibited the best bending properties among those tested.
authors.forename: Shinjiro
authors.initials: S
authors.lastname: Urano
authors.forename: Yasuhiro
authors.initials: Y
authors.lastname: Hotta
authors.forename: Takashi
authors.initials: T
authors.lastname: Miyazaki
authors.forename: Kazuyoshi
authors.initials: K
authors.lastname: Baba
mesh_terms: D000537:Aluminum Oxide / Q000737:chemistry*; D002563:Cerium / Q000737:chemistry*; D002858:Chromium Alloys / Q000737:chemistry; D003188:Composite Resins / Q000737:chemistry*; D003198:Computer Simulation; D016734:Dental Clasps; D003764:Dental Materials / Q000737:chemistry*; D003799:Dental Stress Analysis / Q000295:instrumentation; D003779:Denture Design; D003832:Denture, Partial, Removable; D004548:Elasticity; D020342:Finite Element Analysis; D006801:Humans; D021621:Imaging, Three-Dimensional / Q000379:methods; D008422:Materials Testing; D053761:Nanocomposites / Q000737:chemistry*; D018583:Pliability; D013314:Stress, Mechanical; D013499:Surface Properties; D015040:Zirconium / Q000737:chemistry*
chemical_list: C475766:Ce-TZP-Al2O3; D002858:Chromium Alloys; D003188:Composite Resins; D003764:Dental Materials; D002563:Cerium; D015040:Zirconium; D000537:Aluminum Oxide