The Journal of Korean Academy of Prosthodontics (대한치과보철학회지)

The Korean Academy of Prosthodonitics (대한치과보철학회)
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Clinical convergence angle and rounding radius on tooth preparation for zirconia all-ceramic crown

지르코니아 전부도재관 지대치 삭제시 축면 경사각과 만곡 반경에 대한 조사

  • Kim, Hye-Eun (Department of Prosthodontics, Division of Dentistry, Graduate School, Kyung-Hee University) ;
  • Woo, Yi-Hyung (Department of Prosthodontics, Division of Dentistry, Graduate School, Kyung-Hee University) ;
  • Pae, Ah-Ran (Department of Prosthodontics, Division of Dentistry, Graduate School, Kyung-Hee University) ;
  • Kim, Hyeong-Seob (Department of Prosthodontics, Division of Dentistry, Graduate School, Kyung-Hee University)
  • 김혜은 (경희대학교 대학원 치의학과 치과보철학교실) ;
  • 우이형 (경희대학교 대학원 치의학과 치과보철학교실) ;
  • 배아란 (경희대학교 대학원 치의학과 치과보철학교실) ;
  • 김형섭 (경희대학교 대학원 치의학과 치과보철학교실)
  • Received : 2010.12.09
  • Accepted : 2011.01.08
  • Published : 2011.01.31
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Abstract

Purpose: This article attempted to examine how teeth for restoration is made in a clinical practice and utilize it as future educational material of teeth formation and basic data for additional research. Materials and methods: This experiment investigated the models sent to milling center for production of zirconia crowns. After scanned with Lava CAD/CAM System (3M ESPE, Seefeld, Germany), they are measured on 'ImageJ (version 1.32j, National Institutes of Health, USA)' program and compared and analyzed. Convergence angle from mesio-distal surfaces and bucco-lingual surfaces of each teeth are measured. Also, bucco-lingual diameter of the region lowered as much as 0.4 mm from incisal edge in anterior teeth except canines.(This measure is defined as the Peak 0.4) The analysis of data between each group was conducted by Windows SPSS statistic program, and was proved significant on 95% confidence level by independent t-test, one-way ANOVA and multiple analysis (Sheff${\'{e}}$ test). Results: The mean value of convergence angle was $18.67^{\circ}$ It is ranked as molar ($26.70^{\circ}$) > premolar ($16.87^{\circ}$) > anterior teeth ($14.81^{\circ}$) in the order of mesio-distal convergence angle; anterior teeth ($22.32^{\circ}$) > molar ($20.93^{\circ}$) > premolar ($15.41^{\circ}$) in the order of bucco-lingual convergence angle. The mean value of Peak 0.4 was 1.18 mm. Conclusion: Convergence angle of abutment of zirconia all ceramic crown has difference depending on the location in the arch. Due to the nature of production of zirconia all ceramic crown, convergence angle of abutment and line angle finishing degree can have an effect on internal suitability of restoration.

연구 목적: 지르코니아 보철물을 위한 치아 형성이 실제 임상에서 어떻게 이루어지는지에 대해 조사하고 향후 치아 형성에 대한 교육 자료 및 추가 연구의 기초 자료로 활용하고자 한다. 연구 재료 및 방법: 지르코니아 치관 제작을 위해 milling center에 보내진 모형을 조사하여 Lava CAD/CAM System으로 스캔 한 후 'ImageJ' 프로그램 상에서 측정하여, 이를 비교 분석하였다. 각 치아마다 근원심면과 협설면에서의 축면 경사각을 측정하였다. 또한, 견치를 제외한 전치에서 절단연 0.4 mm 하방 부위의 bucco-lingual diameter 측정하였다. 결과 및 결론: 실험군 내에서 지르코니아 전부도재관을 위한 지대치의 축면 경사각은 $18.67^{\circ}$로 문헌에서 추천하는 각도 보다 크게 나타났다. 지르코니아 완전도재관의 지대치 형성 시 축면 경사각은 협설과 근원심면, 악궁 내 위치에 따라 차이가 있었다. Peak 0.4의 평균값은 1.18 mm로 밀링버의 최소직경을 고려한 요구조건인 0.8 mm 보다 큰 값으로 나타났다. 그러나 선각 부위 rounding 에 관한 추가적인 연구가 필요할 것으로 생각된다.

Keywords

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