Dental and Medical Problems

Dent Med Probl
Index Copernicus (ICV 2020) – 128.41
MEiN – 70 pts
CiteScore (2021) – 2.0
JCI – 0.5
Average rejection rate (2021) – 81.35%
ISSN 1644-387X (print)
ISSN 2300-9020 (online)
Periodicity – quarterly

Download PDF

Dental and Medical Problems

2018, vol. 55, nr 4, October-December, p. 389–394

doi: 10.17219/dmp/95201

Publication type: original article

Language: English

Download citation:

  • BIBTEX (JabRef, Mendeley)
  • RIS (Papers, Reference Manager, RefWorks, Zotero)

Creative Commons BY-NC-ND 3.0 Open Access

The influence of the manufacturing process of rotary files on the shaping of L-shaped canals

Wpływ procesu wytwarzania rotacyjnych pilników endodontycznych na opracowanie kanału w kształcie litery L

Mateusz Radwański1,A,B,C,D,F, Michał Łęski1,A,E,F, Halina Pawlicka1,E,F

1 Department of Endodontics, Medical University of Lodz, Poland


Background. The nickel-titanium alloy used in the production of nickel-titanium files contains approx. 56% nickel and 44% titanium by weight. To improve the properties of nickel-titanium files, the manufacturers introduce some innovations in the production process. Their purpose is primarily to decrease the stiffness of the instruments while increasing the resistance to cyclic fatigue, which reduces the risk of file separation. One of the most popular processes is the heat treatment of the nickel-titanium alloy.
Objectives. The aim of the research was to determine the influence of the manufacturing process of rotary files on the shaping of L-shaped canals.
Material and Methods. Fifty L-shaped resin canals were instrumented (10/group) with ProTaper Universal ®, ProTaper Next®, Hyflex CM®, Hyflex EDM®, or WaveOne Gold® files, with the same apical size of 25. Each L-shaped resin canal was photographed both before and after instrumentation. Differences between the change of the working length and apical transportation were analyzed statistically.
Results. The smallest mean loss of the working length was observed after instrumentation with Hyflex CM files. Statistically significant differences in the working length were found between ProTaper Universal and Hyflex CM (p = 0.0032), ProTaper Universal and Hyflex EDM (p = 0.021), and ProTaper Universal and WaveOne Gold (p = 0.0112) files. The lowest apical transportation was noted in the case of WaveOne Gold files. In terms of apical transportation, statistically significant differences were observed between ProTaper Universal and WaveOne Gold files (p = 0.0254). Shaping Lshaped canals with the ProTaper Universal file system resulted in the greatest changes in the working length (x = 0.35 mm) and apical transportation (x = 0.034 mm).
Conclusion. The study, with its limitations, shows that in the files whose nickel-titanium alloy was subjected to a thermal treatment process, a smaller loss of the working length and lower values of apical transportation were observed.

Key words

nickel-titanium rotary files, canal shaping, resin blocks

Słowa kluczowe

niklowo-tytanowe rotacyjne pilniki endodontyczne, opracowanie kanału, bloki żywicowe

References (30)

  1. Thompson SA. An overview of nickel-titanium alloys used in dentistry. Int Endod J. 2000;33:297–310.
  2. Kuhn G, Jordan L. Fatigue and mechanical properties of nickel-titanium endodontic instruments. J Endod. 2002;28:716–720.
  3. Kuhn G, Tavernier B, Jordan L. Influence of structure on nickel-titanium endodontic instruments failure. J Endod. 2001;27:516–520.
  4. Zinelis S, Darabara M, Takase T, Ogane K, Papadimitriou GD. The effect of thermal treatment on the resistance of nickel-titanium rotary files in cyclic fatigue. Oral Surg Oral Med Oral Pathol Oral Radiol Endod. 2007;103:843–847.
  5. Alapati SB, Brantley WA, Iijima M, et al. Micro-XRD and temperature-modulated DSC investigation of nickel-titanium rotary endodontic instruments. Dent Mater. 2009;25:1221–1229.
  6. Walid N. Review and classification of heat treatment procedures of NiTi instruments and its implication on files fatigue. J Dent Sci. 2017;2:1–19.
  7. Brantley WA, Svec TA, Iijima M, Powers JM, Grentzer TH. Differential scanning calorimetric studies of nickel titanium rotary endodontic instruments. Analysis. 2002;28:774–778.
  8. Hou XM, Yahata Y, Hayashi Y, Ebihara A, Hanawa T, Suda H. Phase transformation behaviour and bending property of twisted nickel-titanium endodontic instruments. Int Endod J. 2011;44:253–258.
  9. Shen Y, Zhou HM, Zheng YF, Campbell L, Peng B, Haapasalo M. Metallurgical characterization of controlled memory wire nickel-titanium rotary instruments. J Endod. 2011;37:1566–1571.
  10. Zhou HM, Shen Y, Zheng W, Li L, Zheng YF, Haapasalo M. Mechanical properties of controlled memory and superelastic nickel-titanium wires used in the manufacture of rotary endodontic instruments. J Endod. 2012;38:1535–1540.
  11. Shen Y, Zhou HM, Zheng YF, Peng B, Haapasalo M. Current challenges and concepts of the thermomechanical treatment of nickel-titanium instruments. J Endod. 2013;39:163–172.
  12. Kell T, Azarpazhooh A, Peters OA, El-Mowafy O, Tompson B, Basrani B. Torsional profiles of new and used 20/.06 GT Series X and GT rotary endodontic instruments. J Endod. 2009;35:1278–1281.
  13. Berendt C. Method of preparing nitinol for use in manufacturing instruments with improved fatigue resistance. United States Patent & Trademark Office, United States Patent Application 20070072147, March 29, 2007.
  14. Ye J, Gao Y. Metallurgical characterization of M-Wire nickel-titanium shape memory alloy used for endodontic rotary instruments during low-cycle fatigue. J Endod. 2012;38:105–107.
  15. Aminsobhani M, Khalatbari MS, Meraji N, Ghorbanzadeh A, Sadri E. Evaluation of the fractured surface of five endodontic rotary instruments: A metallurgical study. Iran Endod J. 2016;11:286–292.
  16. de Arruda Santos L, de Azevedo Bahia MG, de Las Casas EB, Buono VTL. Comparison of the mechanical behavior between controlled memory and superelastic nickel-titanium files via finite element analysis. J Endod. 2013;39:1444–1447.
  17. Testarelli L, Plotino G, Al-Sudani D, et al. Bending properties of a new nickel-titanium alloy with a lower percent by weight of nickel. J Endod. 2011;37:1293–1295.
  18. Shen Y, Coil JM, Zhou H, Zheng Y, Haapasalo M. HyFlex nickel-titanium rotary instruments after clinical use: Metallurgical properties. Int Endod J. 2013;46:720–729.
  19. De Vasconcelos RA, Murphy S, Carvalho CAT, Govindjee RG, Govindjee S, Peters OA. Evidence for reduced fatigue resistance of contemporary rotary instruments exposed to body temperature. J Endod. 2016;42:782–787.
  20. Pereira ESJ, Peixoto IFC, Viana ACD, et al. Physical and mechanical properties of a thermomechanically treated NiTi wire used in the manufacture of rotary endodontic instruments. Int Endod J. 2012;45:469–474.
  21. Otsuka K, Ren X. Physical metallurgy of Ti-Ni-based shape memory alloys. Prog Mater Sci. 2005;50:511–678.
  22. Brantley WA, Alapati SB. Heat treatment of dental alloys: A review. In: Pardhi Y, ed. Metallurgy – Advances in Materials and Processes. London, UK: IntechOpen; 2012:11–15.
  23. Pirani C, Iacono F, Generali L, et al. HyFlex EDM: Superficial features, metallurgical analysis and fatigue resistance of innovative electro discharge machined NiTi rotary instruments. Int Endod J. 2016;49:483–493.
  24. Iacono F, Pirani C, Generali L, et al. Structural analysis of HyFlex EDM instruments. Int Endod J. 2017;50:303–313.
  25. González Sánchez JA, Duran-Sindreu F, de Noé S, Mercadé M, Roig M. Centring ability and apical transportation after overinstrumentation with ProTaper Universal and ProFile Vortex instruments. Int Endod J. 2012;45:542–551.
  26. Yoo YS, Cho YB. A comparison of the shaping ability of reciprocating NiTi instruments in simulated curved canals. Restor Dent Endod. 2012;37:220–227.
  27. Zmener O, Banegas G. Comparison of three instrumentation techniques in the preparation of simulated curved root canals. Int Endod J. 1996;29:315–319.
  28. Bergmans L, Van Cleynenbreugel J, Beullens M, Wevers M, Van Meerbeek B, Lambrechts P. Progressive versus constant tapered shaft design using NiTi rotary instruments. Int Endod J. 2003;36:288–295.
  29. Gu Y, Kum KY, Perinpanayagam H, et al. Various heat-treated nickel-titanium rotary instruments evaluated in S-shaped simulated resin canals. J Dent Sci. 2017;12:14–20.
  30. Liu Y, Qiu N, Xue M, Wang C, Yu X. Comparison of shaping ability of five nickel-titanium rotary instruments in simulated curved canals. J Dent Oral Health. 2017;3.