title: Biaxial flexural strength and phase transformation of Ce-TZP/Al2O3 and Y-TZP core materials after thermocycling and mechanical loading.
abstract: OBJECTIVE
  The purpose of the present study was to evaluate the effect of thermocycling and mechanical loading on the biaxial flexural strength and the phase transformation of one Ce-TZP/Al2O3 and two Y-TZP core materials.
  
  
  METHODS
  Thirty disc-shaped specimens were obtained from each material. The specimens were randomly divided into three groups (control, thermocycled, and mechanically loaded). Thermocycling was subjected in distilled water for 10000 cycles. Mechanical loading was subjected with 200 N loads at a frequency of 2 Hz for 100000 times. The mean biaxial flexural strength and phase transformation of the specimens were tested. The Weibull modulus, characteristic strength, 10%, 5% and 1% probabilities of failure were calculated using the biaxial flexural strength data.
  
  
  RESULTS
  The characteristic strengths of Ce-TZP/Al2O3 specimens were significantly higher in all groups compared with the other tested materials (P<.001). Statistical results of X-ray diffraction showed that thermocycling and mechanical loading did not affect the monoclinic phase content of the materials. According to Raman spectroscopy results, at the same point and the same material, mechanical loading significantly affected the phase fraction of all materials (P<.05).
  
  
  CONCLUSIONS
  It was concluded that thermocycling and mechanical loading did not show negative effect on the mean biaxial strength of the tested materials.
authors.affiliation: Department of Prosthodontics, Faculty of Dentistry, Gazi University, Ankara, Turkey.
authors.forename: Merve
authors.initials: M
authors.lastname: Bankoğlu Güngör
authors.affiliation: Department of Prosthodontics, Faculty of Dentistry, Gazi University, Ankara, Turkey.
authors.forename: Handan
authors.initials: H
authors.lastname: Yılmaz
authors.affiliation: Department of Prosthodontics, Faculty of Dentistry, Gazi University, Ankara, Turkey.
authors.forename: Cemal
authors.initials: C
authors.lastname: Aydın
authors.affiliation: Department of Prosthodontics, Faculty of Dentistry, Gazi University, Ankara, Turkey.
authors.forename: Seçil
authors.initials: S
authors.lastname: Karakoca Nemli
authors.affiliation: Department of Prosthodontics, Faculty of Dentistry, Gazi University, Ankara, Turkey.
authors.forename: Bilge
authors.initials: B
authors.lastname: Turhan Bal
authors.affiliation: Department of Physics, Faculty of Science, Anadolu University, Eskişehir, Turkey.
authors.forename: Tülay
authors.initials: T
authors.lastname: Tıraş
keywords: Ce-TZP/AL2O3; Characteristic strength; Mechanical loading; Phase transformation; Thermocycling; Y-TZP