Effect of Size and Taper on Cyclic Fatigue in EndoMagic Gold M06 Files: An In Vitro Study

Abstract

Aim: The aim of this study was to evaluate the effects of different size and taper combinations of the EndoMagic Gold M06 rotary file system on cyclic fatigue resistance and fragment length, and to investigate the contribution of file geometry to overall mechanical performance. Method: A total of 120 new EndoMagic Gold M06 files (10/06, 15/06, 19/08, 20/06, 25/06, 30/06; n=20 for each group) were used. The files were tested in distilled water at 35 ± 1 °C and positioned in a stainless-steel block with a 60° curvature angle, 5 mm radius, 1.5 mm inner diameter, with the curvature center located 5 mm from the file tip. Files were operated in rotary motion at 300 rpm and 2.2 N/cm torque, following the manufacturer's instructions, until fracture occurred. The number of cycles to fracture (NCF) was calculated by multiplying the fracture time by the rpm value. Fragment lengths were measured using a digital caliper. Data were analyzed using one-way ANOVA followed by post-hoc Tukey tests (p < 0.05). Results: A statistically significant difference was found among the file groups in terms of the number of cycles to fracture (p < 0.05). The 19/08 file exhibited significantly lower NCF values compared to the 15/06 and 25/06 groups, while no significant differences were observed among the other groups. Regarding fragment length, the 19/08 file produced significantly longer fragments than all other file groups (p < 0.05). Conclusion: In the EndoMagic Gold M06 system, increases in file size and taper significantly influence cyclic fatigue resistance and fracture behavior. The 19/08 file, with its greater taper, demonstrated lower fatigue resistance and a more coronal fracture pattern, indicating higher susceptibility to mechanical stress. Clinically, prolonged use of high-taper instruments in severely curved canals should be approached with caution.

Keywords

• Cyclic fatigue
• EndoMagic Gold M06
• Fragment length
• Number of cycles to fracture

EndoMagic Gold M06 Eğelerinde Boyut ve Konikliğin Döngüsel Yorgunluğa Etkisi: Bir İn Vitro Çalışma

Öz

Amaç: Bu çalışmanın amacı, EndoMagic Gold M06 döner eğe sistemine ait farklı boyut ve koniklik kombinasyonlarının döngüsel yorgunluk direnci ve kırık parça uzunluğu üzerindeki etkilerini değerlendirmek ve eğe geometrisinin mekanik performansa katkısını incelemektir. Yöntem: Toplam 120 adet yeni EndoMagic Gold M06 eğe (10/06, 15/06, 19/08, 20/06, 25/06, 30/06; her grup n=20) kullanıldı. Eğeler, 35 ± 1 °C’de distile su içinde, kurvatür merkezi uçtan 5 mm uzaklıkta olacak şekilde; 60° eğrilik açısı, 5 mm yarıçap ve 1,5 mm iç çapa sahip metal blokta sabitlendi. Üretici önerilerine uygun olarak 300 rpm ve 2,2 N/cm tork ile rotary modda kırılıncaya kadar çalıştırıldı. Kırılmaya kadar tur sayısı, kırılma süresinin rpm değeri ile çarpılmasıyla hesaplandı. Kırık parça uzunlukları dijital kumpas ile ölçüldü. Veriler tek yönlü ANOVA ve post-hoc Tukey testi ile değerlendirildi (p < 0,05). Bulgular: Eğe grupları arasında kırılmaya kadar tur sayısı açısından istatistiksel olarak anlamlı fark bulundu (p <0,05). 19/08 eğesi, 15/06 ve 25/06 gruplarından anlamlı düzeyde daha düşük kırılmaya kadar tur sayısı değerleri gösterdi; diğer gruplar arasında fark izlenmedi. Kırık parça uzunluğu açısından 19/08 eğesi tüm gruplardan daha uzun kırık fragmanı oluşturdu (p < 0,05). Sonuç: EndoMagic Gold M06 sisteminde eğe boyutu ve koniklik artışı döngüsel yorgunluk direncini ve kırık davranışını belirgin biçimde etkilemektedir. Yüksek konikliğe sahip 19/08 eğesi, daha düşük döngüsel yorgunluk direnci ve daha koronal kırık eğilimiyle artmış mekanik gerilime daha duyarlıdır. Klinik açıdan, yüksek koniklikteki eğelerin şiddetli eğimli kanallarda uzun süreli kullanımından kaçınılması önerilmektedir.

Anahtar Kelimeler

• Döngüsel yorgunluk
• EndoMagic Gold M06
• Kırık parça uzunluğu
• Kırılmaya kadar tur sayısı

Kaynakça

1. Schilder H. Cleaning and shaping the root canal. Dent Clin North Am. 1974; 18: 269-96.
2. Schilder H. Filling root canals in three dimensions. Dent Clin North Am. 1967; 11: 723-44.
3. Walia HM, Brantley WA, Gerstein H. An initial investigation of the bending and torsional properties of Nitinol root canal files. J Endod. 1988; 14: 346-51.
4. Kosa DA, Marshall G, Baumgartner JC. An analysis of canal centering using mechanical instrumentation techniques. J Endod. 1999; 25: 441-5.
5. Tsujimoto M, Irifune Y, Tsujimoto Y, et al. Comparison of conventional and new-generation nickel-titanium files in regard to their physical properties. J Endod. 2014; 40: 1824-9.
6. Lopes HP, Elias CN, Vedovello GA, et al. Torsional resistance of retreatment instruments. J Endod. 2011; 37: 1442-5.
7. Shen Y, Cheung GS, Bian Z, et al. Comparison of defects in ProFile and ProTaper systems after clinical use. J Endod. 2006; 32: 61-5.
8. Pruett JP, Clement DJ, Carnes DL. Cyclic fatigue testing of nickel-titanium endodontic instruments. J Endod. 1997; 23: 77-85.

9. Gao Y, Shotton V, Wilkinson K, et al. Effects of raw material and rotational speed on the cyclic fatigue of ProFile Vortex rotary instruments. J Endod. 2010; 36: 1205-9.
10. All In Dental. M-PRO Gold Rotary File System – Technical Specifications. Kocaeli, Türkiye NiTi Alloy Inspection Report (ASTM F2063 compliant). S1.2 Test Report, 2024.
11. NiTi Wire for Medical Application. Material Safety Data Sheet (MSDS), 2025.
12. Faus-Llácer V, Kharrat NH, Ruiz-Sánchez C, et al. The effect of taper and apical diameter on the cyclic fatigue resistance of rotary endodontic files using an experimental electronic device. Applied Sci. 2021; 11: 863.
13. Pedulla E, Lizio A, Scibilia M, et al. Cyclic fatigue resistance of two nickel-titanium rotary instruments in interrupted rotation. Int Endod J. 2017; 50: 194-201.
14. Shen Y, Zhou HM, Zheng YF, et al. Metallurgical characterization of controlled memory wire nickel-titanium rotary instruments. J Endod. 2011; 37: 1566-71.
15. Zupanc J, Vahdat-Pajouh N, Schafer E. New thermomechanically treated NiTi alloys - a review. Int Endod J. 2018; 51: 1088-103.
16. Martins JNR, Silva EJNL, Marques D, et al. Design, metallurgical features, and mechanical behaviour of niti endodontic instruments from five different heat-treated rotary systems. Materials. 2022; 15: 1009.
17. El Feky HM, Ezzat KM, Bedier MMA. Cyclic fatigue resistance of M-Pro and RaCe Ni-Ti rotary endodontic instruments in artificial curved canals: a comparative in vitro study. Restor Dent Endod. 2019; 44: E44.
18. Abdellatif D, Iandolo A, Scorziello M, et al. Cyclic fatigue of different ni-ti endodontic rotary file alloys: a comprehensive review. Bioengineering (Basel). 2024; 11: 499.
19. Silva E, Zanon M, Hecksher F, et al. Influence of autoclave sterilization procedures on the cyclic fatigue resistance of heat-treated nickel-titanium instruments: a systematic review. Restor Dent Endod. 2020; 45: E25.
20. Hiran-Us S, Morakul S. Effect of temperatures on cyclic fatigue resistance of 3 different Ni-Ti alloy files. Int Dent J. 2023; 73: 904-9.
21. Hwang KC, Choi JJE, Hussaini HM, et al. Effect of diabetes and hyperglycaemia on the physical and mechanical properties of dentine: a systematic review. Clin Oral Investig. 2025; 29: 55.
22. Kinney JH, Marshall SJ, Marshall GW. The mechanical properties of human dentin: a critical review and re-evaluation of the dental literature. Crit Rev Oral Biol Med. 2003; 14: 13-29.
23. Plotino G, Grande NM, Cordaro M, et al. A review of cyclic fatigue testing of nickel-titanium rotary instruments. J Endod. 2009; 35: 1469-76.