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Comparison of torque, force generation and canal shaping ability between manual and nickel-titanium glide path instruments in rotary and optimum glide path motion

  • Pyae Hein Htun
  • Arata EbiharaEmail author
  • Keiichiro Maki
  • Shunsuke Kimura
  • Miki Nishijo
  • Daisuke Tokita
  • Takashi Okiji
Original Article


This study aimed to analyze force/torque generation and canal volume changes of NiTi rotary glide path preparation using HyFlex EDM Glide Path File in comparison to manual stainless steel K-file instrumentation. Thirty extracted mandibular incisors with a minimally curved and narrow root canal were randomly divided into three groups (n = 10) according to the instrumentation kinematics: Optimum Glide Path motion (OGP) or continuous rotation (CR) with HyFlex EDM Glide Path Files using a custom-made automated-root-canal-preparation device and manual instrumentation with stainless steel K-files (SS) in watch-winding motion. Torque and force were monitored with a custom-made torque/force analyzing device. Canal volume changes and transportation values were measured on micro-computed tomographic images taken before and after the glide path preparation. The data were statistically evaluated using Kruskal–Wallis test and Mann–Whitney U test with Bonferroni correction, with a significance level set at 5%. Maximum upward apical force, representing the screw-in force, was lower in groups OGP and CR compared with that in group SS (P < 0.05). Group CR showed the highest maximum clockwise torque value and canal volume changes, followed by groups OGP and SS (P < 0.05). Canal transportation values at 1 and 3 mm from the apex were not significantly different among groups. Within the limitations of this study, rotary glide path preparation generated smaller screw-in force, larger torque and larger canal volume changes than manual preparation. OGP motion generated smaller torque and less canal volume changes than CR.


Canal volume changes Optimum glide path motion Rotary glide path preparation Screw-in force Torque 



This study was supported in part by Grants-in-Aid for Young Scientists from the Ministry of Education, Culture, Sports, Science and Technology, Japan (B)(15K20400).

Compliance with ethical standards

Conflict of interest

The authors declare that they have no conflict of interest.

Supplementary material

10266_2019_455_MOESM1_ESM.tiff (24.6 mb)
Online Resource 1. Determination of the degree of root canal curvature with Schneider’s method [18]. A straight line parallel to the long axis of the canal is drawn from the mid-point of the file at the level of the canal orifice. A second straight line is drawn from the apical foramen to the point where the file starts to deviate from the long axis of the canal. The acute angle formed by the intersection of two straight lines is measured (TIFF 25149 kb)


  1. 1.
    Peters OA, Peters CI, Basrani B. Cleaning and shaping the root canal system. In: Hargreaves KM, Berman LH, editors. Cohen’s pathways of the pulp. 11th ed. St. Louis: Elsevier; 2016. p. 209–79.Google Scholar
  2. 2.
    Ajuz NCC, Armada L, Gonçalves LS, Debelian G, Siqueira JF Jr. Glide path preparation in S-shaped canals with rotary pathfinding nickel-titanium instruments. J Endod. 2013;39:534–7.CrossRefPubMedGoogle Scholar
  3. 3.
    Berutti E, Cantatore G, Castellucci A, Chiandussi G, Pera F, Migliaretti G, Pasqualini D. Use of nickel-titanium rotary PathFile to create the glide path: comparison with manual preflaring in simulated root canals. J Endod. 2009;35:408–12.CrossRefPubMedGoogle Scholar
  4. 4.
    Pasqualini D, Bianchi CC, Paolino DS, Mancini L, Cemenasco A, Cantatore G, Castellucci A, Berutti E. Computed micro-tomographic evaluation of glide path with nickel-titanium rotary PathFile in maxillary first molars curved canals. J Endod. 2012;38:389–93.CrossRefPubMedGoogle Scholar
  5. 5.
    Shi L, Wagle S. Comparing the centering ability of different pathfinding systems and their effect on final instrumentation by Hyflex CM. J Endod. 2017;43:1868–71.CrossRefPubMedGoogle Scholar
  6. 6.
    Rowan MB, Nicholls JI, Steiner J. Torsional properties of stainless steel and nickel-titanium endodontic files. J Endod. 1996;22:341–5.CrossRefPubMedGoogle Scholar
  7. 7.
    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;21:146–51.CrossRefPubMedGoogle Scholar
  8. 8.
    Short JA, Morgan LA, Baumgartner JC. A comparison of canal centering ability of four instrumentation techniques. J Endod. 1997;23:503–7.CrossRefPubMedGoogle Scholar
  9. 9.
    Aydin ZU, Keskin NB, Özyürek T, Geneci F, Ocak M, Çelik HH. Microcomputed assessment of transportation, centering ratio, canal area, and volume increase after single-file rotary and reciprocating glide path instrumentation in curved root canals: a laboratory study. J Endod. 2019. Scholar
  10. 10.
    Paleker F, van der Vyver PJ. Comparison of canal transportation and centering ability of K-files, ProGlider File, and G-Files: a micro-computed tomography study of curved root canals. J Endod. 2016;42:1105–9.CrossRefPubMedGoogle Scholar
  11. 11.
    Nishijo M, Ebihara A, Tokita D, Doi H, Hanawa T, Okiji T. Evaluation of selected mechanical properties of NiTi rotary glide path files manufactured from controlled memory wires. Dent Mater J. 2018;37:549–54.CrossRefPubMedGoogle Scholar
  12. 12.
    Ha JH, Lee CJ, Kwak SW, El Abed R, Ha D, Kim HC. Geometric optimization for development of glide path preparation nickel-titanium rotary instrument. J Endod. 2015;41:916–9.CrossRefPubMedGoogle Scholar
  13. 13.
    Ha JH, Park SS. Influence of glide path on the screw-in effect and torque of nickel-titanium rotary files in simulated resin root canals. Restor Dent Endod. 2012;37:215–9.CrossRefPubMedPubMedCentralGoogle Scholar
  14. 14.
    Capar ID, Kaval ME, Ertas H, Sen BH. Comparison of the cyclic fatigue resistance of 5 different rotary pathfinding instruments made of conventional nickel-titanium wire, M-wire, and controlled memory wire. J Endod. 2015;41:535–8.CrossRefPubMedGoogle Scholar
  15. 15.
    Pedullà E, Lo Savio F, Boninelli S, Plotino G, Grande NM, La Rosa G, Rapisarda E. Torsional and cyclic fatigue resistance of a new nickel-titanium instrument manufactured by electrical discharge machining. J Endod. 2016;42:156–9.CrossRefPubMedGoogle Scholar
  16. 16.
    Uslu G, Özyürek T, Yilmaz K, Gündoğar M. Cyclic fatigue resistance of R-Pilot, HyFlex EDM and PathFile nickel-titanium glide path files in artificial canals with double (S-shaped) curvature. Int Endod J. 2018;51:584–9.CrossRefPubMedGoogle Scholar
  17. 17.
  18. 18.
    Schneider SW. A comparison of canal preparations in straight and curved root canals. Oral Surg Oral Med Oral Pathol Oral Radiol Endod. 1971;32:271–5.CrossRefGoogle Scholar
  19. 19.
    Tokita D, Ebihara A, Nishijo M, Miyara K, Okiji T. Dynamic torque and vertical force analysis during nickel-titanium rotary root canal preparation with different modes of reciprocal rotation. J Endod. 2017;43:1706–10.CrossRefPubMedGoogle Scholar
  20. 20.
    Gambill JM, Alder M, del Rio CE. Comparison of nickel-titanium and stainless steel hand-file instrumentation using computed tomography. J Endod. 1996;22:369–75.CrossRefPubMedGoogle Scholar
  21. 21.
    Hülsmann M. Mechanical preparation of root canals: shaping goals, techniques and means. Endod Top. 2005;10:30–76.CrossRefGoogle Scholar
  22. 22.
    Blum JY, Machtou P, Esber S, Micallef JP. Analysis of forces developed during root canal preparation with the balanced force technique. Int Endod J. 1997;30:386–96.CrossRefPubMedGoogle Scholar
  23. 23.
    Peters OA, Laib A, Göhring TN, Barbakow F. Changes in root canal geometry after preparation assessed by high-resolution computed tomography. J Endod. 2001;27:1–6.CrossRefPubMedGoogle Scholar
  24. 24.
    Sattapan B, Nervo GJ, Palamara JE, Messer HH. Defects in rotary nickel-titanium files after clinical use. J Endod. 2000;26:161–5.CrossRefPubMedGoogle Scholar
  25. 25.
    Ha JH, Cheung GS, Versluis A, Lee CJ, Kwak SW, Kim HC. ‘Screw-in’ tendency of rotary nickel-titanium files due to design geometry. Int Endod J. 2015;48:666–72.CrossRefPubMedGoogle Scholar
  26. 26.
    Yılmaz K, Uslu G, Özyürek T. In vitro comparison of the cyclic fatigue resistance of HyFlex EDM, One G, and ProGlider nickel titanium glide path instruments in single and double curvature canals. Restor Dent Endod. 2017;42:282–9.CrossRefPubMedPubMedCentralGoogle Scholar
  27. 27.
    Gambarini G, Piasecki L, Miccoli G, Gaimari G, Di Giorgio R, Di Nardo D, Azim AA, Testarelli L. Classification and cyclic fatigue evaluation of new kinematics for endodontic instruments. Aust Endod J. 2018. Scholar
  28. 28.
    Gabel WP, Hoen M, Steiman HR, Pink FE, Dietz R. Effect of rotational speed on nickel-titanium file distortion. J Endod. 1999;25:752–4.CrossRefPubMedGoogle Scholar
  29. 29.
    Ha JH, Kwak SW, Sigurdsson A, Chang SW, Kim SK, Kim HC. Stress generation during pecking motion of rotary nickel-titanium instruments with different pecking depth. J Endod. 2017;43:1688–91.CrossRefPubMedGoogle Scholar
  30. 30.
    Maki K, Ebihara A, Kimura S, Nishijo M, Tokita D, Okiji T. Effect of different speeds of up-and-down motion on canal centering ability and vertical force and torque generation of nickel-titanium rotary instruments. J Endod. 2019;45:68–72.CrossRefPubMedGoogle Scholar
  31. 31.
    Bürklein S, Stüber JP, Schäfer E. Real-time dynamic torque values and axial forces during preparation of straight root canals using three different endodontic motors and hand preparation. Int Endod J. 2019;52:94–104.CrossRefPubMedGoogle Scholar
  32. 32.
    Melo MC, Pereira ES, Viana AC, Fonseca AM, Buono VT, Bahia MG. Dimensional characterization and mechanical behaviour of K3 rotary instruments. Int Endod J. 2008;41:329–38.CrossRefPubMedGoogle Scholar
  33. 33.
    Alves Vde O, Bueno CE, Cunha RS, Pinheiro SL, Fontana CE, de Martin AS. Comparison among manual instruments and PathFile and Mtwo rotary instruments to create a glide path in the root canal preparation of curved canals. J Endod. 2012;38:117–20.CrossRefPubMedGoogle Scholar

Copyright information

© The Society of The Nippon Dental University 2019

Authors and Affiliations

  • Pyae Hein Htun
    • 1
  • Arata Ebihara
    • 1
    Email author
  • Keiichiro Maki
    • 1
  • Shunsuke Kimura
    • 1
  • Miki Nishijo
    • 1
  • Daisuke Tokita
    • 1
  • Takashi Okiji
    • 1
  1. 1.Department of Pulp Biology and Endodontics, Division of Oral Health Sciences, Graduate School of Medical and Dental SciencesTokyo Medical and Dental University (TMDU)TokyoJapan

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