The Journal of Korean Academy of Prosthodontics (대한치과보철학회지)

The Korean Academy of Prosthodonitics (대한치과보철학회)
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AN EVALUATION OF FRACTURE TOUGHNESS OF DENTAL CERAMICS BY INDENTATION FRACTURE METHOD

압자압입법에 의한 치과용 도재의 파괴인성 평가

  • Ahn, Seung-Geun (Dept. of prosthodonties, School of Dentistry, Chonbuk University) ;
  • Lee, Ju-Hyung (Dept. of Dental Materials, School of Dentistry, Chonbuk University) ;
  • Bae, Tae-Sung (Dept. of Dental Materials, School of Dentistry, Chonbuk University)
  • 안승근 (전북대학교 치과대학 보철학교실) ;
  • 이주형 (전북대학교 치과대학 치과재료학) ;
  • 배태성 (전북대학교 치과대학 치과재료학)
  • Published : 1996.11.01
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Abstract

This study was performed to evaluate the fracture toughness of seven commercially available dental ceramics by indentation fracture method. All specimens were fabricated to the final dimensions of approximately 12mm in diameter 2mm in thickness. The characte-ristic indentation dimensions of Vickers or Knoop indentation were measured to calculate the fracture toughness values and Young’s moduli. The results obtained were summarized as follows; 1. Young’s modulus and Vickers hardness of Vita In-Ceram showed the maximum values of $154.4{\pm}49.2$ Gpa and $12.60{\pm}0.71$Gpa, respectively. Results of Scheff test exhibited the significant difference between Vita In-Ceram group and others(p<0.01). 2. Maximum fracture toughness of $2.562{\pm}0.37 MPam^{1/2}$ for Vita In-Ceram and the maxi-mum one of $0.908{\pm}0.132MPam^{1/2}$ for Vitadur-N were calculated. Results of Scheff test showed the significant difference between Vita In-Ceram group and Vita Hi-Ceram(p<0.05) : also between Vita In-Ceram or Vita Hi-Ceram and others(p<0.01). 3. The alumina-based core ceramics showed the aspect of Palmqvist crack for the indentation load of 49.0N, but others showed the median/lateral crack for the indentation load of 9.8N.

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