title: The influence of rotating fatigue on the bond strength of zirconia-composite interfaces.
abstract: OBJECTIVE
  To evaluate the effect of cyclic loading on the bond strength of resin composite to zirconia framework material.
  
  
  METHODS
  Bar shaped zirconia/composite specimens (2 mm x 2 mm x 25 mm) were prepared using three different resin cements and placed in a four-point bending test setup. The flexure strength (F(s)) was calculated by placing the bars (n=10) fixed between the four supports (at 10 and 20 mm) with the interface centered between the inner rollers and subsequently loaded (1 mm/min crosshead speed) until fracture. Rotating fatigue resistance (RFR) was determined in a rotating bending cantilever test setup (104, 1.2 Hz) with the highest stress located at the interface (n=20). The RFR was determined by the staircase method and the mean RFR was calculated using logistic regression analysis.
  
  
  RESULTS
  Resin cement composition had no significant influence on the bond strength value obtained by both F(s) (F=0.6, P> or =0.5) and RFR (F=1.1, P> or =0.3) tests. However, after rotating fatigue testing there was a significant reduction in bond strength between 46 and 50% of the three resin cements.
  
  
  CONCLUSIONS
  Zirconia resin bond strength is liable to deterioration under the influence of fatigue.
authors.affiliation: Department of Dental Materials Science, Academic Centre of Dentistry Amsterdam (ACTA), Universiteit van Amsterdam and Vrije Universiteit, The Netherlands. hmirmoha@acta.nl
authors.forename: Hesam
authors.initials: H
authors.lastname: Mirmohammadi
authors.forename: Moustafa N
authors.initials: MN
authors.lastname: Aboushelib
authors.forename: Cornelis J
authors.initials: CJ
authors.lastname: Kleverlaan
authors.forename: Niek
authors.initials: N
authors.lastname: de Jager
authors.forename: Albert J
authors.initials: AJ
authors.lastname: Feilzer
mesh_terms: D000704:Analysis of Variance; D003188:Composite Resins; D001840:Dental Bonding; D003776:Dental Porcelain; D003799:Dental Stress Analysis / Q000379:methods; D020342:Finite Element Analysis; D016015:Logistic Models; D008422:Materials Testing; D018583:Pliability; D019279:Resin Cements / Q000737:chemistry; D012399:Rotation; D015040:Zirconium
chemical_list: D003188:Composite Resins; C438843:Panavia-Fluoro; C483701:Rely X Unicem; D019279:Resin Cements; C502351:multilink adhesive system; D003776:Dental Porcelain; D015040:Zirconium; C028541:zirconium oxide