title: Fracture behavior of metal-ceramic fixed dental prostheses with frameworks from cast or a newly developed sintered cobalt-chromium alloy.
abstract: OBJECTIVE
  The aim of this study was to investigate the fracture behavior of metal-ceramic bridges with frameworks from cobalt-chromium-molybdenum (CoCrMo), which are manufactured using conventional casting or a new computer-aided design/computer-aided manufacturing (CAD/CAM) milling and sintering technique.
  
  
  METHODS
  A total of 32 metal-ceramic fixed dental prostheses (FDPs), which are based on a nonprecious metal framework, was produced using a conventional casting process (n = 16) or a new CAD/CAM milling and sintering process (n = 16). Eight unveneered frameworks were manufactured using each of the techniques. After thermal and mechanical aging of half of the restorations, all samples were subjected to a static loading test in a universal testing machine, in which acoustic emission monitoring was performed. Three different critical forces were revealed: the fracture force (F max), the force at the first reduction in force (F decr1), and the force at the critical acoustic event (F acoust1).
  
  
  RESULTS
  With the exception of the veneered restorations with cast or sintered metal frameworks without artificial aging, which presented a statistically significant but slightly different F max, no statistically significant differences between cast and CAD/CAM sintered and milled FDPs were detected. Thermal and mechanical loading did not significantly affect the resulting forces.
  
  
  CONCLUSIONS
  Cast and CAD/CAM milled and sintered metal-ceramic bridges were determined to be comparable with respect to the fracture behavior.
  
  
  CONCLUSIONS
  FDPs based on CAD/CAM milled and sintered frameworks may be an applicable and less technique-sensitive alternative to frameworks that are based on conventionally cast frameworks.
authors.affiliation: Department of Prosthetic Dentistry and Dental Materials Sciences, Dental School and Clinics, Saarland University, Homburg Campus, Bldg. 71.2, 66421, Homburg/Saar, Germany.
authors.forename: Klaus-Peter
authors.initials: KP
authors.lastname: Krug
authors.forename: Andreas W
authors.initials: AW
authors.lastname: Knauber
authors.forename: Frank P
authors.initials: FP
authors.lastname: Nothdurft
mesh_terms: D003830:Denture, Partial, Fixed; D016876:Metal Ceramic Alloys; D008855:Microscopy, Electron, Scanning; D013499:Surface Properties
chemical_list: D016876:Metal Ceramic Alloys