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Lifetime and fracture patterns of NiTi rotary files in molars


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Lifetime and fracture patterns of NiTi rotary files in molars

Article information

Restor Dent Endod. 2005;30(3):184-192
Publication date (electronic) : 2005 May 31
doi : https://doi.org/10.5395/JKACD.2005.30.3.184
Jin-Woo Kim, Byung-Doo Ahn, Se-Hee Park, Hye-Jin Shin, Kyung-Mo Cho
Department of Conservative Dentistry, College of Dentistry, Kangnung National University, Korea.
Corresponding author: Jin-Woo Kim. Department of Conservative Dentistry, College of Dentistry, Kangnung National University, Jibyun-Dong, Kangnung City, Kangwon-Do, Korea, 210-702. Tel: 82-33-640-3189, Fax: 82-33-640-3113, mendo7@kangnung.ac.kr
Received 2004 October 27; Revised 2004 December 08; Accepted 2005 February 16.

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.

Keywords: NiTi file; separation; Unwinding; SEM

References

1. Schilder H. Cleaning and shaping the root canal. Dent Clin North Am 1974. 18269–296.
2. Skidmore AE, Bjorndal AM. Root canal morphology of the human mandibular first molar. Oral Surg Oral Med Oral Pathol 1971. 32778–784.
3. Weine F, Kelly R, Lio P. The effect of preparation procedures on the original canal shape and on apical foramen shape. J Endod 1975. 1255–262.
4. Walia H, Brantely WA, Gerstein H. An initial investigation of the bending and torsional properties of nitinol root canal files. J Endod 1988. 14346–351.
5. Glossen CR, Haller RH, Dove SB, del Rio CE. A comparison of root canal preparations using Ni-Ti hand, Ni-Ti engine-driven, and K-Flex endodontic instruments. J Endod 1995. 21146–151.
6. Serene TP, Adams JD, Saxena A. Nickel-titanium instruments: applications in endodontics 1995. St. Louis: Mosby; 67–78.
7. Barbakow F, Lutz F. The "Lightspeed" preparation technique evaluated by Swiss clinicians after attending continuing education courses. Int Endod J 1997. 3046–50.
8. Zuolo ML, Walton RE. Instrument deterioration with usage: Nickel-Titanium versus stainless steel. Quintessence Int 1997. 28397–402.
9. Mandel E, Adib-Yazdi M, Benhamou LM, Lachkar T, Mesgouez , Sobel M. Rotary Ni-Ti profile systems for preparing curved canals in resin blocks: influence of operator on instrument breakage. Int Endod J 1999. 32436–443.
10. Ruddle C. Cleaning and shaping the root canal system. Pathways of the Pulp 2002. 8th edth ed. Mosby: St. Louis; 231–292.
11. Sattapan B, Nervo GJ, Palamara JEA, Messer HH. Defect in rotary nickel-titanium files after clinical use. J Endod 2000. 26161–165.
12. Haikel Y, Serfaty R, Bateman G, Senger B, Allemann C. Dynamic and cyclic fatigue of engine-driven rotary nickel-titanium endodontic instrument. J Endod 1999. 25434–440.
13. Gambarini G. Cyclic fatigue of Profile rotary instruments after prolonged clinical use. Int Endod J 2001. 34386–389.
14. Pruett JP, Clement DJ, Carnes DL Jr. Cyclic fatigue testing of nickel-titanium endodontic instruments. J Endod 1997. 2377–85.
15. Gary C. Influence of material properties on the rotational speed of engine-driven nickel-titanium instrument. Contemporary Endod 2002. 28–30.
16. Mize SB, Clement DJ, Carnes DL, Pruett JP. Effect of sterilization on cyclic fatigue of Ni-Ti instruments. Abstracts of research. AAE 54th session. J Endod 1997. 23(OR9)251.
17. Yared GM, Bou Dagher FE, Machtou P. Cyclic fatigue of Profile rotary instruments after clinical use. Int Endod J 2000. 33204–207.
18. Peters OA, Barbakow F. Dynamic torque and apical forced of ProFile .04 rotary instruments during preparation of curved canals. Int Endod J 2002. 35379–389.
19. Booth JR, Sheetz JP, Lemons JE, Eleazer PD. A comparison of torque reqiured to fracture three different nickel-titanium rotary instruments around curves of the same angle but of different radius when bound at the tip. J Endod 2003. 2955–57.
20. Gambarini G. Cyclic fatique of nickel-titanium rotary instruments after clinical use with low- and high torque endodontic motors. J Endod 2001. 27772–774.
21. Cho JC, et al. Metal Failure Analysis 2002. Seoul: Jinyoungsa; 15–41.
22. Lee DR. Mechanical Metallurgy 1985. Seoul: Moonundang; 219–291.
23. Zinelis S, Margelos J. In : Eliades G, Eliades T, Brantley W, Watt DC, eds. Aging of endodontic instruments and materials. Dental materials in vivo: aging and related phenomena. Carol Stream 2003. Carol Stream: Quintessence Publishing Co Inc; 180–186.

Article information Continued

Copyright © 2005 Korean Academy of Conservative Dentistry
(open-access) :

This is an Open Access article distributed under the terms of the Creative Commons Attribution Non-Commercial License (http://creativecommons.org/licenses/by-nc/3.0/) which permits unrestricted non-commercial use, distribution, and reproduction in any medium, provided the original work is properly cited.

Figure 1

Figure 1

SEM photographs of representative fracture surface.

a: ProFile group b: ProTaper group

c: K3 flaring group d: K3 shaping group

Figure 2

Figure 2

SEM photoghaph of representative cutting blade.

Files shown are (from top to bottom): K3 #20/.06, new K3 #20/.06, ProFile #20/.06 and new ProFile #20/.06. Unwinding of K3 file was seen to the point of fracture.

Table 1

Angle and radius of curvature of root canals in this study

Table 1

Table 2

Classification of NiTi rotary file used in this study

Table 2

Table 3

Mean numbers of the canals which one file could prepare

Table 3

†: (# of fractured files / # of unwinding files).

*: Statistically significant difference, p < 0.05 by Mann-Whitney test.