CC BY 4.0 · Journal of Health and Allied Sciences NU 2023; 13(02): 168-171
DOI: 10.1055/s-0042-1753492
Review Article

Impact of a Retained Instrument on Treatment Outcome: A Systematic Review

Lakshmi Nidhi Rao
1   Department of Conservative Dentistry and Endodontics, ABSMIDS, Nitte (Deemed to be University), Mangalore, Karnataka, India
Sembaga Lakshmi Thirunarayanan
1   Department of Conservative Dentistry and Endodontics, ABSMIDS, Nitte (Deemed to be University), Mangalore, Karnataka, India
Aditya Shetty
1   Department of Conservative Dentistry and Endodontics, ABSMIDS, Nitte (Deemed to be University), Mangalore, Karnataka, India
› Author Affiliations


Instrument separation during endodontic therapy is a frequent accident with rotary instruments being more likely to separate than manual ones. There are various treatment options when the instrument separates in a canal depending on the location, complexity of the canal anatomy, and the operators' ability. The success of the tooth that has a retained fragment of instrument in the canal has been assessed in various studies but no clear conclusion has been drawn. The goal of this systematic review is to answer as many questions as possible. Does the retention of a separated instrument, compared with no retained separated instrument, result in a worse clinical outcome in adult patients who have received nonsurgical root canal treatment?

Materials and Methodology The search was conducted with the boolean terms in various database following the PRISMA guidelines. The inclusion and exclusion criteria were set for the inclusion of the study for the systematic review.

Results Out of the 330 articles that were obtained, 28 were duplicates. After screening for eligibility, only 7 articles were retrieved for full text. When inclusion and exclusion criteria were applied, none of the studies could be included.

Conclusion There is still a lack of consensus on the treatment option for a separated instrument and there is no clear evidence to suggest whether the prognosis of the tooth with retained instrument is reduced or not.

Publication History

Article published online:
08 August 2022

© 2022. The Author(s). This is an open access article published by Thieme under the terms of the Creative Commons Attribution License, permitting unrestricted use, distribution, and reproduction so long as the original work is properly cited. (

Thieme Medical and Scientific Publishers Pvt. Ltd.
A-12, 2nd Floor, Sector 2, Noida-201301 UP, India

  • References

  • 1 Torabinejad M, Lemon RR. Procedural accidents. In: Walton R, Torabinejad M. eds. Principles and practice of endodontics. Philadelphia: W.B. Saunders Company; 2002: 310-330
  • 2 Rambabu T. Management of fractured endodontic instruments in root canal: a review. J Sci Dent. 2014; 4 (02) 40-48
  • 3 Serene TP, Adams JD, Saxena A. Nickel-titanium instruments. Applications in endodontics. St. Louis, MO: Ishiyaku EuroAmerica, Inc.,; 1995
  • 4 Otsuka K, Wayman CM. Shape Memory Alloys. Cambridge: Cambridge University Press; 1998
  • 5 Sattapan B, Nervo GJ, Palamara JEA, Messer HH. Defects in rotary nickel-titanium files after clinical use. J Endod 2000; 26 (03) 161-165
  • 6 Simon S, Machtou P, Tomson P, Adams N, Lumley P. Influence of fractured instruments on the success rate of endodontic treatment. Dent Update 2008; 35 (03) 172-174 , 176, 178–179
  • 7 Gabel WP, Hoen M, Steiman HR, Pink FE, Dietz R. Effect of rotational speed on nickel-titanium file distortion. J Endod 1999; 25 (11) 752-754
  • 8 Yared GM, Bou Dagher FE, Machtou P. Cyclic fatigue of ProFile rotary instruments after clinical use. Int Endod J 2000; 33 (03) 204-207
  • 9 Parashos P, Gordon I, Messer HH. Factors influencing defects of rotary nickel-titanium endodontic instruments after clinical use. J Endod 2004; 30 (10) 722-725
  • 10 Engström B, Hård L, Segerstad AF, Ramström G, Frostell G. Correlation of positive cultures with the prognosis for root canal treatment. Odontol Revy 1964; 15: 257-270
  • 11 Engström B, Lundberg M. The correlation between positive culture and the prognosis of root canal therapy after pulpectomy. Odontol Revy 1965; 16 (03) 193-203
  • 12 Tordai B, Schreindorfer K, Lempel E, Krajczár K. Factors affecting ultrasonic removal of separated endodontic instruments: A retrospective clinical study. Quintessence Int 2018; 49 (04) 257-266
  • 13 Farid H, Khan FR, Rahman M. ProTaper rotary instrument fracture during root canal preparation: a comparison between rotary and hybrid techniques. Oral Health Dent Manag 2013; 12 (01) 50-55
  • 14 Shahabinejad H, Ghassemi A, Pishbin L, Shahravan A. Success of ultrasonic technique in removing fractured rotary nickel-titanium endodontic instruments from root canals and its effect on the required force for root fracture. J Endod 2013; 39 (06) 824-828
  • 15 Madarati AA, Qualtrough AJ, Watts DC. Effect of retained fractured instruments on tooth resistance to vertical fracture with or without attempt at removal. Int Endod J 2010; 43 (11) 1047-1053
  • 16 Mohammadi Z, Khademi AA. Effect of a separated rotary instrument on bacterial penetration of obturated root canals. J Clin Dent 2006; 17 (05) 131-133
  • 17 Cunha RS, Junaid A, Ensinas P, Nudera W, Bueno CE. Assessment of the separation incidence of reciprocating WaveOne files: a prospective clinical study. J Endod 2014; 40 (07) 922-924
  • 18 Tygesen YA, Steiman HR, Ciavarro C. Comparison of distortion and separation utilizing profile and Pow-R nickel-titanium rotary files. J Endod 2001; 27 (12) 762-764
  • 19 Siqueira Jr JF. Aetiology of root canal treatment failure: why well-treated teeth can fail. Int Endod J 2001; 34 (01) 1-10
  • 20 Vouzara T, , el Chares M, Lyroudia K. Separated instrument in endodontics: frequency, treatment and prognosis. Balkan Journal of Dental Medicine. 2018; 22 (03) 123-132
  • 21 Murad M, Murray C. Impact of retained separated endodontic instruments during root canal treatment on clinical outcomes remains uncertain. J Evid Based Dent Pract 2011; 11 (02) 87-88
  • 22 Miccoli G, Seracchiani M, Zanza A, Giudice AD, Testarelli L. Possible Complications of Endodontic Treatments. J Contemp Dent Pract 2020; 21 (05) 473-474