Evaluation of the effect of temperature on cyclic fatigue resistance of three types of Nickel-Titanium rotary files with various alloy properties: An in vitro study

  • Dara H. Saeed Department of Conservative Dentistry, College of Dentistry, Hawler Medical University.
  • Fadi A. Rafea Department of Conservative Dentistry (M.Sc. student), College of Dentistry, Hawler Medical University
Keywords: Cyclic fatigue, files, nickel-titanium, temperature


Background and objectives: the fracturing of nickel-titanium rotary instruments during endodontic treatment because of the cyclic fatigue remains a common incidence. This study evaluated the effect of temperature on the cyclic fatigue of various nickel-titanium rotary files and compare between them.

Methods: Three types of rotary instruments with tip size 0.25 were used: HyFlex EDM (OneFile, variable taper, Colten/Whaledent), ProTaper Gold (F2, 0.08 taper, Dentsply) and 2Shape (TS2, 0.06 taper, Micro-Mega). Twenty files for each instrument were tested for cyclic fatigue at (20°C and 37°C) temperatures and rotated until fracture occurred in a simulated canal with an angle curvature of about 60°, a radius curvature of 5 mm, and a canal width of 1.5 mm. Six groups were formed for all instruments (total number = 60), with ten files in each group. The number of cycles to fracture was recorded, and statistical analysis was completed using analysis of variance and independent t-test with significance at a (P<0.05).

Results: HyFlex EDM OneFile registered no differences in fatigue life between the 2 temperatures tested (P > .05), whereas ProTaper Gold F2 and 2Shape TS2 showed a statistically significant reduction in fatigue life at body temperature compared with room temperature ( P <0.05). HyFlex EDM OneFile exhibited statistically higher resistance to cyclic fatigue than ProTaper Gold F2 and 2Shape TS2 both at room and body temperatures (P<0.05).

Conclusions: Within the limitations of this study, body temperature influenced the cyclic fatigue resistance of ProTaper Gold F2 and 2Shape TS2 files, whereas it did not influence the fatigue life of HyFlex EDM OneFile. The HyFlex EDM OneFile was more resistant to cyclic fatigue than the ProTaper Gold F2 and 2Shape TS2 files at room and body temperatures.


Arias A, Perez-Higueras JJ, de la Macorra JC. Differences in cyclic fatigue resistance at apical and coronal levels of Reciproc and WaveOne new files. J Endod. 2012;38:1244–1248.

Perez-Higueras JJ, Arias A, de la Macorra JC. Cyclic fatigue resistance of K3, K3XF, and twisted file nickel-titanium files under continuous rotation or reciprocating motion. J Endod. 2013;39:1585–1588.

McGuigan MB, Louca C, Duncan HF. Clinical decision-making after endodontic instrument fracture. Br Dent J. 2013;214:395–400.

Sattapan B, Nervo GJ, Palamara JE, Messer HH. Defects in rotary nickel-titanium files after clinical use. J Endod. 2000;26:161–165.

Pedulla E, Savio FL, Boninelli S, et al. Torsional and cyclic fatigue resistance of a new nickel-titanium instrument manufactured by electrical discharge machining. J Endod. 2016;42:156–159.

Bouska J, Justman B, Williamson A, et al. Resistance to cyclic fatigue failure of a new endodontic rotary file. J Endod. 2012;38:667–669.

Setzer FC, Bohme CP. Influence of combined cyclic fatigue and torsional stress on the fracture point of nickel-titanium rotary instruments. J Endod. 2013;39:133–137.

Kim HC, Kwak SW, Cheung GS, Ko DH, Chung SM, Lee W. Cyclic fatigue and torsional resistance of two new nickel-titanium instruments used in reciprocation motion: Reciproc versus WaveOne. J Endod. 2012;38:541–544.

Peters O, Gluskin A, Weiss R, Han J. An in vitro assessment of the physical properties of novel Hyflex nickel–titanium rotary instruments. Int Endod J. 2012;45:1027–1034.

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.

Hieawy A, Haapasalo M, Zhou H, et al. Phase transformation behavior and resistance to bending and cyclic fatigue of ProTaper Gold and ProTaper Universal instruments. J Endod. 2015;41:1134–1138.

Uygun AD, Kol E, Topcu MK, et al. Variations in cyclic fatigue resistance among ProTaper Gold, ProTaper Next and ProTaper Universal instruments at different levels. Int Endod J. 2016;49:494–499.

MicroMega. The 2Shape brochure. Available at: http://www.denta.be/pdf/MicroMega-2shape-ENG.pdf. 2017 (last accessed 10/2018).

Elnaghy A. Cyclic fatigue resistance of ProTaper next nickel titanium rotary files. Int Endod J. 2014;47:1034–1039.

Plotino G, Grande NM, Cotti E, et al. Blue treatment enhances cyclic fatigue resistance of vortex nickel-titanium rotary files. J Endod. 2014;40:1451–1453.

de Hemptinne F, Slaus G, Vandendael M, et al. In vivo intracanal temperature evolution during endodontic treatment after the injection of room temperature or preheated sodium hypochlorite. J Endod. 2015;41:1112–1115.

Jamleh A, Yahata Y, Ebihara A, et al. Performance of NiTi endodontic instrument under different temperatures. Odontology. 2016;104:324–328.

de Vasconcelos RA, Murphy S, Carvalho CA, et al. Evidence for reduced fatigue resistance of contemporary rotary instruments exposed to body temperature. J Endod. 2016;42:782–787.

Dosanjh A, Paurazas S, Askar M. The Effect of temperature on cyclic fatigue of nickel-titanium rotary endodontic instruments. J Endod. 2017;43:823–826.

Pruett JP, Clement DJ, Carnes DL Jr. Cyclic fatigue testing of nickel-titanium endodontic instruments. J Endod. 1997;23:77–85.

Larsen CM, Watanabe I, Glickman GN, He J. Cyclic fatigue analysis of a new generation of nickel titanium rotary instruments. J Endod. 2009;35:401–403.

Grande, N. M., Plotino, G., Silla, E., Pedullà, E., Dedeus, G., Gambarini, G., & Somma, F. (2017). Environmental Temperature Drastically Affects Flexural Fatigue Resistance of Nickel-titanium Rotary Files. J Endod, 43(7), 1157-1160.

Plotino G, Grande NM, Cordaro M, Testarelli L, Gambarini G. A review of cyclic fatigue testing of nickel-titanium rotary instruments. J Endod. 2009;35:1469–1476.

Iacono F, Pirani C, Generali L et al. (2017) Structural analysis of HyFlex EDM instruments. Int Endod J 50, 303-13.

Arias, A., Macorra, J. C., Govindjee, S., & Peters, O. A. (2018). Correlation between Temperature-dependent Fatigue Resistance and Differential Scanning Calorimetry Analysis for 2 Contemporary Rotary Instruments. J Endod, 44(4), 630-634.

Kaval ME, Capar ID, Ertas H. Evaluation of the cyclic fatigue and torsional resistance of novel nickel-titanium rotary files with various alloy properties. J Endod. 2016;42:1840–1843.

Özyürek T, Gündoğar M, Uslu G, et al. Cyclic fatigue resistances of Hyflex EDM, WaveOne gold, Reciproc blue and 2shape NiTi rotary files in different artificial canals. Odontology. 2018;106(4):408–413.

Gündoğar M, Özyürek T. Cyclic fatigue resistance of OneShape, HyFlex EDM, WaveOne gold, and Reciproc blue nickel-titanium instruments. J Endod. 2017;43:1192–1196.

Cheung GS, Zhang EW, Zheng YF. A numerical method for predicting the bending fatigue life of NiTi and stainless steel root canal instruments. Int Endod J. 2011;44:357–361.

How to Cite
Saeed, D., & Rafea, F. (2019). Evaluation of the effect of temperature on cyclic fatigue resistance of three types of Nickel-Titanium rotary files with various alloy properties: An in vitro study. Erbil Dental Journal (EDJ), 2(1), 157-163. https://doi.org/10.15218/edj.2019.05
Original Articles