Separation of Nickel-Titanium Rotary and Reciprocating Instruments: A Mini-Review of Clinical Studies

Marcelo Santos Coelho1, *, Marcos de Azevêdo Rios2, Carlos Eduardo da Silveira Bueno1
1 Department of Endodontics, São Leopoldo Mandic Dental Research Center, Campinas, SP, Brazil
2 Department of Endodontics, State University of Feira de Santana, Feira de Santana, Brazil

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Creative Commons License
© 2018 Coelho et al.

open-access license: This is an open access article distributed under the terms of the Creative Commons Attribution 4.0 International Public License (CC-BY 4.0), a copy of which is available at: ( This license permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.

* Address correspondence to this author at the Department of Endodontics, São Leopoldo Mandic Dental Research Center, Rua José Rocha Junqueira, 13, Campinas - SP, Brazil; Tel: +55 19 98111 6525, Email:



This review aimed to evaluate clinical studies that assessed separated NiTi rotary and reciprocating instruments.

Design and Methods:

This review assessed clinical studies involving treatments performed by undergraduate students, graduate students, and endodontic specialists. This review evaluated studies using rotary instruments, reciprocating instruments, and hybrid techniques. The number of uses of the different NiTi rotary and reciprocating systems was also assessed.


The incidence of separation for rotary instruments ranged from 0% to 23%. Rotary instruments were used from 1 to 50 times depending on the instrument and tooth type. The lowest rate of incidence separation for rotary instruments was obtained by undergraduate students, using a hybrid technique. The separation incidence for reciprocating instruments ranged from 0% to 1.71%. Reciprocating instruments were mostly single-used; one study reported their use up to 3 times. Separation rate in reciprocating instruments was similar in single-use or in multiple uses 0.2%.


Separation of instruments has dropped recently and seems to be a minor problem in current Endodontics. Multiple uses of NiTi rotary instruments are a possibility without significantly increasing the risk of instrument separation. Single and multiple uses of NiTi reciprocating instruments are also associated with low incidence of separation. Attempting to remove separated instruments should be carefully evaluated.

Keywords: Nickel-titanium, Root canal treatment, Rotary, Reciprocating, Separation, Dentinal defects.