Cyclic Fatigue Resistance and SEM Evaluation of Fractured Instrument Surfaces; Comparison of ProTaper Universal and ProTaper Gold Files

Abstract

Purpose:To compare the cyclic fatigue resistance of ProTaper Universal (PTU) and ProTaper Gold (PTG) nickel titanium files at different angles and to examine the fractured surface areas by using scanning electron microscope (SEM). Materials and Methods: A special static test device made of stainless steel with artificial canals at 3 different angles. The files were rotated until they were broken in artificial canals with 45°, 60° and 90° angles and also the time was recorded using a digital stopwatch. The number of cycles to failure was calculated for each instrument. Statistical analyzes were made by using one-way analysis of variance (Anova) for comparison between main groups. Results: PTG files showed higher fatigue resistance (p<0.001) than PTU files in all groups. SEM results displayed similar characteristic structures in pits and fissures caused by fracture due to cyclic fatigue regardless of angle and file type. Conclusion: Although surface properties of broken instruments do not play a decisive role in clinical practice it was observed that heat-treated Ni-Ti files exhibited higher fatigue resistance at all angles compared to conventional files according to the number of cycles during experimental period

Keywords

• Cyclic fatigue
• Fractured instrument
• ProTaper Gold
• ProTaper Universal
• Scanning Electron Microscopy

References

1. 1. Peters OA. Current challenges and concepts in the preparation of root canal systems: a review. J Endod. 2004;30(8):559-67.
2. 2. Schäfer E, Schulz-Bongert U, Tulus G. Comparison of hand stainless steel and nickel titanium rotary instrumentation: a clinical study. J Endod. 2004;30(6):432-5.
3. 3. Walia H, Brantley WA, Gerstein H. An initial investigation of the bending and torsional properties of Nitinol root canal files. Journal of endodontics. 1988;14(7):346-51.
4. 4. Bird DC, Chambers D, Peters OA. Usage parameters of nickel-titanium rotary instruments: a survey of endodontists in the United States. J Endod. 2009;35(9):1193-7.
5. 5. Sattapan B, Nervo GJ, Palamara JE, Messer HH. Defects in rotary nickel-titanium files after clinical use. J Endod. 2000;26(3):161-5.
6. 6. Young JM, Van Vliet KJ. Predicting in vivo failure of pseudoelastic NiTi devices under low cycle, high amplitude fatigue. J Biomed Mater Res B Appl Biomater. 2005;72(1):17-26.
7. 7. Jamleh A, Alghaihab A, Alfadley A, Alfawaz H, Alqedairi A, Alfouzan K. Cyclic Fatigue and Torsional Failure of EdgeTaper Platinum Endodontic Files at Simulated Body Temperature. J Endod. 2019;45(5):611-4.
8. 8. Turpin YL, Chagneau F, Vulcain JM. Impact of two theoretical cross-sections on torsional and bending stresses of nickel-titanium root canal instrument models. J Endod. 2000;26(7):414-7.

9. 9. Tripi TR, Bonaccorso A, Condorelli GG. Cyclic fatigue of different nickel-titanium endodontic rotary instruments. Oral Surg Oral Med Oral Pathol Oral Radiol Endod. 2006;102(4):e106-14.
10. 10. Alapati SB, Brantley WA, Iijima M, Clark WA, Kovarik L, Buie C, et al. Metallurgical characterization of a new nickel-titanium wire for rotary endodontic instruments. J Endod. 2009;35(11):1589-93.
11. 11. Hieawy A, Haapasalo M, Zhou H, Wang ZJ, Shen Y. Phase Transformation Behavior and Resistance to Bending and Cyclic Fatigue of ProTaper Gold and ProTaper Universal Instruments. J Endod. 2015;41(7):1134-8.
12. 12. 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(2):163-72.
13. 13. Uygun AD, Kol E, Topcu MK, Seckin F, Ersoy I, Tanriver M. Variations in cyclic fatigue resistance among ProTaper Gold, ProTaper Next and ProTaper Universal instruments at different levels. Int Endod J. 2016;49(5):494-9.
14. 14. Plotino G, Grande NM, Sorci E, Malagnino VA, Somma F. Influence of a brushing working motion on the fatigue life of NiTi rotary instruments. Int Endod J. 2007;40(1):45-51.
15. 15. Fishelberg G, Pawluk JW. Nickel-titanium rotary-file canal preparation and intracanal file separation. Compend Contin Educ Dent. 2004;25(1):17-8, 20-2, 4; quiz 5, 47.
16. 16. Mounce R. Rotary nickel titanium instrumentation. A literature review. Dent Today. 2004;23(2):119-20, 24-6, 28; quiz 29.
17. 17. Yao JH, Schwartz SA, Beeson TJ. Cyclic fatigue of three types of rotary nickel-titanium files in a dynamic model. J Endod. 2006;32(1):55-7.
18. 18. 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(11):1469-76.
19. 19. Grande NM, Plotino G, Pecci R, Bedini R, Malagnino VA, Somma F. Cyclic fatigue resistance and three-dimensional analysis of instruments from two nickel-titanium rotary systems. Int Endod J. 2006;39(10):755-63.
20. 20. Pruett JP, Clement DJ, Carnes DL, Jr. Cyclic fatigue testing of nickel-titanium endodontic instruments. J Endod. 1997;23(2):77-85.
21. 21. Haïkel Y, Serfaty R, Bateman G, Senger B, Allemann C. Dynamic and cyclic fatigue of engine-driven rotary nickel-titanium endodontic instruments. J Endod. 1999;25(6):434-40.
22. 22. Ruiz-Sánchez C, Faus-Matoses V, Alegre-Domingo T, Faus-Matoses I, Faus-Llácer VJ. An in vitro cyclic fatigue resistance comparison of conventional and new generation nickel-titanium rotary files. J Clin Exp Dent. 2018;10(8):e805-e9.
23. 23. Alqedairi A, Alfawaz H, Bin Rabba A, Almutairi A, Alnafaiy S, Khan Mohammed M. Failure analysis and reliability of Ni–Ti-based dental rotary files subjected to cyclic fatigue. Metals. 2018;8(1):36.
24. 24. Elnaghy AM, Elsaka SE. Mechanical properties of ProTaper Gold nickel-titanium rotary instruments. Int Endod J. 2016;49(11):1073-8.
25. 25. Plotino G, Grande NM, Bellido MM, Testarelli L, Gambarini G. Influence of temperature on cyclic fatigue resistance of ProTaper Gold and ProTaper Universal rotary files. Journal of endodontics. 2017;43(2):200-2.
26. 26. 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(12):1840-3.
27. 27. Nguyen HH, Fong H, Paranjpe A, Flake NM, Johnson JD, Peters OA. Evaluation of the resistance to cyclic fatigue among ProTaper Next, ProTaper Universal, and Vortex Blue rotary instruments. J Endod. 2014;40(8):1190-3.