The Journal of Korean Academy of Prosthodontics (대한치과보철학회지)

The Korean Academy of Prosthodonitics (대한치과보철학회)
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AN EVALUATION OF DYNAMIC FATIGUE CHARACTERISTICS OF DENTAL CERAMICS FOR ALL-CERAMIC CROWN

All-ceramic Crown 용 도재의 동적 피로특성 평가

  • Yu, Hyoung-Woo (Dept. of Prosthodontics, and Institute of Dental Science, School of Dentistry, Chonbuk National University) ;
  • Bae, Tae-Sung (Dept. of Dental Materials, School of Dentistry. Chonbuk University) ;
  • Song, Kwang-Yeob (Dept. of Prosthodontics, and Institute of Dental Science, School of Dentistry, Chonbuk National University) ;
  • Park, Charn-Woon (Dept. of Prosthodontics, and Institute of Dental Science, School of Dentistry, Chonbuk National University)
  • 유형우 (전북대학교 치과대학 치과보철학교실 및 치의학연구소) ;
  • 배태성 (전북대학교 치과대학 치과재료학교실) ;
  • 송광엽 (전북대학교 치과대학 치과보철학교실 및 치의학연구소) ;
  • 박찬운 (전북대학교 치과대학 치과보철학교실 및 치의학연구소)
  • Published : 1997.12.01
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Abstract

This study was peformed to evaluate the dynamic fatigue characteristics of the dental ceramics for all-ceramic crown. A feldspathic porcelain of VMK68. glass ceramic of IPS-Empress, and glass infiltrated alumina ceramic of In-Ceram were used. Disc specimens were prepared to the final dimensions of 12 mm in diameter and 1 mm in thickness. The biaxial flexure test was conducted using a ball-on-three-ball method. 240 specimens were tested in $37^{\circ}C$ water by testing 20 samples at each of four loading rates:0.05, 0.2, 1, and 5mm/min. 60 specimens were tested in a moisture-free environment by testing 20 samples at 5mm/min. The inert strength of VMK68 was 80.25MPa, and the fatigue parameters were n=29.1, ${\sigma}_{fo}=52.90MPa$. The inert strength of IPS-Empress was 104.76MPa, and the fatigue parameters were n=32.46, ${\sigma}_{fo}=67.52MPa$. The inert strength of In-Ceram was 429.33MPa, and the fatigue parameters were n=31.46, ${\sigma}_{fo}=258.36MPa$. 10-year failure stresses of VMK68, IPS-Empress, and In-Ceram were 20.3MPa, 24.8MPa, and 93.6MPa, respectively. Failure strength and fatigue life showed the highest value in In-Ceram, and then, IPS-Empress and VMK68.

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