Evaluation of apical canal shapes produced sequentially during instrumentation with stainless steel hand and Ni-Ti rotary instruments using Micro-computed tomography

Stainless steel hand file과 Ni-Ti rotary file을 이용한 근관 형성시 근단부 근관 형태의 순차적 변화에 대한 평가

  • Lee, Woo-Jin (Department of Conservative Dentistry and Dental Research Institute, College of Dentistry, Seoul National University) ;
  • Lee, Jeong-Ho (Department of Conservative Dentistry and Dental Research Institute, College of Dentistry, Seoul National University) ;
  • Chun, Kyung-A (Department of Conservative Dentistry, Korea University Anam Hospital) ;
  • Seo, Min-Seock (Hanyang University Seoul Hospital) ;
  • Yoo, Yeon-Jee (Department of Conservative Dentistry and Dental Research Institute, College of Dentistry, Seoul National University) ;
  • Baek, Seung-Ho (Department of Conservative Dentistry and Dental Research Institute, College of Dentistry, Seoul National University)
  • 이우진 (서울대학교 치과대학 치과보존학교실) ;
  • 이정호 (서울대학교 치과대학 치과보존학교실) ;
  • 전경아 (고려대학교 안암의료원 치과보존과) ;
  • 서민석 (한양대학교 서울병원) ;
  • 유연지 (서울대학교 치과대학 치과보존학교실) ;
  • 백승호 (서울대학교 치과대학 치과보존학교실)
  • Received : 2011.04.11
  • Accepted : 2011.04.29
  • Published : 2011.05.31


Objectives: The purpose of this study was to determine the optimal master apical file size with minimal transportation and optimal efficiency in removing infected dentin. We evaluated the transportation of the canal center and the change in untouched areas after sequential preparation with a #25 to #40 file using 3 different instruments: stainless steel K-type (SS K-file) hand file, ProFile and LightSpeed using microcomputed tomography (MCT). Materials and Methods: Thirty extracted human mandibular molars with separated orifices and apical foramens on mesial canals were used. Teeth were randomly divided into three groups: SS K-file, Profile, LightSpeed and the root canals were instrumented using corresponding instruments from #20 to #40. All teeth were scanned with MCT before and after instrumentation. Cross section images were used to evaluate canal transportation and untouched area at 1-, 2-, 3-, and 5- mm level from the apex. Data were statistically analyzed according to 'repeated nested design' and Mann-Whitney test (p = 0.05). Results: In SS K-file group, canal transportation was significantly increased over #30 instrument. In the ProFile group, canal transportation was significantly increased after preparation with the #40 instrument at the 1- and 2- mm levels. LightSpeed group showed better centering ability than ProFile group after preparation with the #40 instrument at the 1 and 2 mm levels. Conclusions: SS K-file, Profile, and LightSpeed showed differences in the degree of apical transportation depending on the size of the master apical file.

연구목적: 본 연구에서는 micro CT를 사용하여 SS K-file, Profile, LightSpeed로 #25부터 #40 크기까지 근관을 형성할 때 근단부 근관 형태의 연속되는 변화를 평가하였다. 연구 재료 및 방법: 30개 하악 대구치의 근심 근관을 ProFile, LightSpeed와 SS K-file로 #25번에서 #40번까지 순차적으로 근관 형성하였고, 매 단계 확대 후 micro CT를 시행하였다. 치근단 1, 2, 3, 5 mm 에서 근관 중심 변위와 삭제되지 않은 단면의 비율을 측정하여 'repeated nested design' 분석방법과 Mann-Whitney test로 유의 수준 p = 0.05에서 검정하였다. 결과: SS K-file군에서 #30 이상 근관 형성 후 유의할 만한 근관 중심 변위가 증가하였고, 근관 형성 과정 어느 단계에서도 삭제되지 않은 면적의 비율이 유의성 있게 감소되지 않았다. ProFile군에서는 치근단 1, 2 mm에서 #40 file로 근관 형성 후 근관 중심 변위가 크게 증가하였고, 치근단 1 mm에서 #35 크기로 근관 형성한 후에 삭제되지 않은 면적의 비율이 유의성 있게 감소하였다. LightSpeed군에서는 급격한 근관 중심 변위를 관찰할 수 없었고, 근관 중심 변위가 ProFile군보다 적게 관찰되었다. 결론: SS K-file, Profile, LightSpeed에서 형성되는 근관의 변이 정도는 근단부 근관 형성 크기에 따라 다르게 나타났다.



  1. Kerekes K, Tronstad L. Morphometric observations on the root canals of human molars. J Endod 1977;3:114-118.
  2. Gani O, Visvisian C. Apical canal diameter in the first upper molar at various ages. J Endod 1999;25:689-691.
  3. Short JA, Morgan LA, Baumgartner JC. A comparison of canal centering ability of four instrumentation techniques. J Endod 1997;23:503-507.
  4. Albrecht LJ, Baumgartner JC, Marshall JG. Evaluation of apical debris removal using various sizes and tapers of ProFile GT files. J Endod 2004;30:425-428.
  5. Rhodes JS, Ford TR, Lynch JA, Liepins PJ, Curtis RV. Micro-computed tomography: a new tool for experimental endodontology. Int Endod J 1999;32:165-170.
  6. Rhodes JS, Ford TR, Lynch JA, Liepins PJ, Curtis RV. A comparison of two nickel-titanium instrumentation techniques in teeth using microcomputed tomography. Int Endod J 2000;33:279-285.
  7. Bergmans L, Van Cleynenbreugel J, Wevers M, Lambrechts P. A methodology for quantitative evaluation of root canal instrumentation using microcomputed tomography. Int Endod J 2001;34:390-398.
  8. Schneider SW. A comparison of canal preparations in straight and curved root canals. Oral Surg Oral Med Oral Pathol 1971;32:271-275.
  9. Lee JH, Kim MJ, Seok CI. Evaluation of canal preparation with Ni-Ti rotary files by micro computed tomography. J Kor Acad Cons Dent 2004;29:378-385.
  10. Bramante CM, Berbert A, Borges RP. A methodology for evaluation of root canal instrumentation. J Endod 1987;13:243-245.
  11. Ko HJ, Baek SH. A study of histomorphological change of curved root canal preparation using GT rotary file, profile and stainless steel K-file. J Kor Acad Cons Dent 2002;27:612-621.
  12. Gluskin AH, Brown DC, Buchanan LS. A reconstructed computerized tomographic comparison of Ni-Ti rotary GT files versus traditional instruments in canals shaped by novice operators. Int Endod J 2001;34:476-484.
  13. Wu MK, Fan B, Wesselink PR. Leakage along apical root fillings in curved root canals. Part I: effects of apical transportation on seal of root fillings. J Endod 2000;26:210-216.
  14. Deplazes P, Peters O, Barbakow F. Comparing apical preparations of root canals shaped by nickel-titanium rotary instruments and nickel-titanium hand instruments. J Endod 2001;27:196-202.
  15. Thompson SA, Dummer PM. Shaping ability of Lightspeed rotary nickel-titanium instruments in simulated root canals. Part 2. J Endod 1997;23:742-747.
  16. Versumer J, Hulsmann M, Schafers F. A comparative study of root canal preparation using Profile .04 and Lightspeed rotary Ni-Ti instruments. Int Endod J 2002;35:37-46.
  17. Iqbal MK, Maggiore F, Suh B, Edwards KR, Kang J, Kim S. Comparison of apical transportation in four Ni-Ti rotary instrumentation techniques. J Endod 2003;29:587-591.
  18. Ruddle CJ. Cleaning and shaping the root canal system. In: Cohen S, Burns RC, eds. Pathways of the pulp. 8th ed. St. Louis: C.V Mosby; 2002. p231-245.
  19. Griffiths IT, Chassot AL, Nascimento MF, Bryant ST, Dummer PM. Canal shapes produced sequentially during instrumentation with Quantec SC rotary nickeltitanium instruments: a study in simulated canals. Int Endod J 2001;34:107-112.
  20. Peters OA, Laib A, Go¨hring TN, Barbakow F. Changes in root canal geometry after preparation assessed by high-resolution computed tomography. J Endod 2001;27:1-6.
  21. Kosa DA, Marshall G, Baumgartner JC. An analysis of canal centering using mechanical instrumentation techniques. J Endod 1999;25:441-445.
  22. Peters OA, Schonenberger K, Laib A. Effects of four Ni-Ti preparation techniques on root canal geometry assessed by micro computed tomography. Int Endod J 2001;34:221-230.
  23. Wu MK, Wesselink PR. A primary observation on the preparation and obturation of oval canals. Int Endod J 2001;34:137-141.
  24. Paque F, Ganahl D, Peters OA. Effects of root canal preparation on apical geometry assessed by micro-computed tomography. J Endod 2009;35:1056-1059.