title: Fracture resistance of five different metal framework designs for metal-ceramic restorations.
abstract: OBJECTIVE
  This study evaluated fracture resistance of five different metal framework designs for metal-ceramic restorations.
  
  
  METHODS
  Twenty-five artificial crowns were fabricated with different degrees of facial metal reduction: metal collar (group 1), and 0, 0.5, 1, and 1.5 mm (groups 2 to 5, respectively). All of the crowns were thermocycled in two different baths of 5 and 60 degrees C for 20 seconds and had a dwell time of 10 seconds in a resting bath at 37 degrees C for 510 cycles. The artificial crowns were then subjected to vertical loading until fracture with a Shimadzu testing machine at a cross-head speed of 1 mm/min. The load at fracture was recorded.
  
  
  RESULTS
  There were no statistically significant differences between mean fracture strength of groups 1 and 2 or between groups 4 and 5. There were significant differences between group 3 and groups 1, 2, 4, and 5.
  
  
  CONCLUSIONS
  As the amount of metal reduction increased, the vertical fracture resistance decreased. Failure loads for all test groups exceeded normal biting forces.
authors.affiliation: Department of Prosthodontics, School of Dentistry, Ege University, Izmir, Turkey. ulusoyms@yahoo.com
authors.forename: Mübin
authors.initials: M
authors.lastname: Ulusoy
authors.forename: Suna
authors.initials: S
authors.lastname: Toksavul
mesh_terms: D000704:Analysis of Variance; D001732:Bite Force; D003442:Crowns; D003776:Dental Porcelain / Q000737:chemistry; D017267:Dental Prosthesis Design; D019232:Dental Restoration Failure; D003799:Dental Stress Analysis / Q000295:instrumentation; D006801:Humans; D008422:Materials Testing; D016876:Metal Ceramic Alloys / Q000737:chemistry*; D013223:Statistics as Topic; D013314:Stress, Mechanical; D013499:Surface Properties; D013816:Thermodynamics; D016474:Weight-Bearing
chemical_list: D016876:Metal Ceramic Alloys; D003776:Dental Porcelain