title: Flexural strengths of implant-supported zirconia based bridges in posterior regions.
abstract: OBJECTIVE
  Impact forces in implant supported FDP (fixed dental prosthesis) are higher than that of tooth supported FDPs and the compositions used in frameworks also has a paramount role for biomechanical reasons. The aim of this study was to evaluate the flexural strength of two different zirconia frameworks.
  
  
  METHODS
  Two implant abutments with 3.8 mm and 4.5 mm platform were used as premolar and molar. They were mounted vertically in an acrylic resin block. A model with steel retainers and removable abutments was fabricated by milling machine; and 10 FDP frameworks were fabricated for each Biodenta and Cercon systems. All samples were thermo-cycled for 2000 times in 5-55℃ temperature and embedded in 37℃ artificial saliva for one week. The flexural test was done by a rod with 2 mm ending diameter which was applied to the multi-electromechanical machine. The force was inserted until observing fracture. The collected data were analyzed with SPSS software ver.15, using Weibull modulus and independent t-test with the level of significance at α=.05.
  
  
  RESULTS
  The mean load bearing capacity values were higher in Biodenta but with no significant differences (P>.05). The Biodenta frameworks showed higher load bearing capacity (F0=1700) than Cercon frameworks (F0=1520) but the reliability (m) was higher in Cercon (m=7.5).
  
  
  CONCLUSIONS
  There was no significant difference between flexural strengths of both zirconia based framework systems; and both Biodenta and Cercon systems are capable to withstand biting force (even parafunctions) in posterior implant-supported bridges with no significant differences.
authors.affiliation: Dental Implants Research Center, Department of Prosthodontics, School of Dentistry, Isfahan University of Medical Sciences, Isfahan, Iran.
authors.forename: Mansour
authors.initials: M
authors.lastname: Rismanchian
authors.affiliation: Torabinezhad Dental Research Center, Department of Prosthodontics, School of Dentistry, Isfahan University of Medical Sciences, Isfahan, Iran.
authors.forename: Soufia
authors.initials: S
authors.lastname: Shafiei
authors.affiliation: Dental Students Research Center, School of Dentistry, Isfahan University of Medical Sciences, Isfahan, Iran.
authors.forename: Farzaneh
authors.initials: F
authors.lastname: Nourbakhshian
authors.affiliation: Dental Students Research Center, School of Dentistry, Isfahan University of Medical Sciences, Isfahan, Iran.
authors.forename: Amin
authors.initials: A
authors.lastname: Davoudi
keywords: Flexural strength; Implant-supported prosthesis; Weibull modulus; Zirconia