Restorative Dentistry and Endodontics

The Korean Academy of Conservative Dentistry (대한치과보존학회)
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LIFETIME AND FRACTURE PATTERNS OF NITI ROTARY FILES IN MOLARS

대구치에서 회전식 NiTi file의 수명과 파절양상

  • Kim, Jin-Woo (Department of Conservative Dentistry, College of Dentistry, Kangnung National University) ;
  • Ahn, Byung-Doo (Department of Conservative Dentistry, College of Dentistry, Kangnung National University) ;
  • Park, Se-Hee (Department of Conservative Dentistry, College of Dentistry, Kangnung National University) ;
  • Shin, Hye-Jin (Department of Conservative Dentistry, College of Dentistry, Kangnung National University) ;
  • Cho, Kyung-Mo (Department of Conservative Dentistry, College of Dentistry, Kangnung National University)
  • 김진우 (강릉대학교 치과대학 치과보존학교실) ;
  • 안병두 (강릉대학교 치과대학 치과보존학교실) ;
  • 박세희 (강릉대학교 치과대학 치과보존학교실) ;
  • 신혜진 (강릉대학교 치과대학 치과보존학교실) ;
  • 조경모 (강릉대학교 치과대학 치과보존학교실)
  • Published : 2005.05.01
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Abstract

Intracanal separation of the rotary files is a serious concern in modern endodontic practice. The objective of this study was to compare the life span and fracture patterns of three NiTi rotary files in molar teeth Mesiobuccal roots of upper molar (n = 150) and mesial roots of lower molar (n = 150) were divided into three groups and each group was prepared with Profile, ProTaper, and K3 respectively. Every file was used until separation and/or deterioration of the cutting blade was happened, and then the number of canals to separation and/or unwinding were recorded. Radiographs and Scanning electon microscope (SEM) photographs were taken to evaluate the patterns of separation. The results were as follows: 1. There were no significant differences in numbers of canals to separation and/or unwinding among the groups. 2. Comparing between flaring files, K3 showed significant lower numbers of canals to separation and/or unwinding (p < 0.05), and there was no significant difference between shaping files 3. Separations of instruments were occurred at the midpoint of curvatures within the canals 4. In SEM observations, ductile fractures were seen in most of cases, characterized by shallow dimples. Additional researches is needed to provide a new guideline that informs the appropriate number of times to use NiTi files.

회전식 NiTi file은쉽게 파절되는 단점이 있으나 이에 대한 연구는 아직 부족하다. 본 연구에서는 회전식 NiTi file을 이용해 실제 치아에서 근관을 형성하고, 이 때 발생하는 파절 및 변형을 연구, 분석하였다. 상악 대구치의 근심협측 치근 (n = 150)과 하악 대구치의 근심치근 (n = 150)을 실험대상으로 하여 Profile, ProTaper 및 K3로 각각 근관형성 하였다. 각 file은 파절되거나 변형이 생길 때까지 계속하여 사용한 다음 그 사용횟수를 기록하였다. 파절의 양상을 관찰하기 위해 방사선 및 주사현미경 사진을 촬영하였다. 1 세 군간의 유의할만한 사용횟수의 차이는 없었다. 2. Flaring file 간의 비교에서는 K3의 사용횟수가 통계적으로 유의성 있게 적었으며 (p < 0.05), shaping file 간에는 유의할만한 차이가 없었다. 3, 회전식 NiTi file의 파절은 근관의 최대 만곡부에서 발생하였다. 4. 주사전자현미경으로 파절면을 관찰한 결과 연성파괴의 전형적인 양상인 얕은 딤플이 관찰되었다. 일반적으로 회전식 NiTi file의 평균 사용횟수는 제조회사의 사용지침보다는 길었으며, NiTi file의 수명에 대한 새로운 사용지침을 만들기 위한 부가적인 연구가 있어야 되리라 사료된다.

Keywords

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