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Asian Journal of Dental and Health Sciences 
Open Access to Dental and Medical Research 

Copyright  © 2025 The  Author(s): This is an open-access article distributed under the terms of the CC BY-NC 4.0 
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Instrument Retrieval in Endodontics: A Literature Review 

Dr Pavithra Gopal *1 , Dr H Murali Rao 2 , Dr B S Keshava Prasad 3 , Dr Sahana Umesh 4 , Dr Rashmi 
Shetty 5  

1 Post Graduate, MDS, Department of conservative dentistry and Endodontics, DAPM RV Dental College, Bengaluru, Karnataka 560078 

2 Professor, Department of conservative dentistry and Endodontics, DAPM RV Dental College, Bengaluru, Karnataka 560078 

3 Professor and Head of the department, Department of conservative dentistry and Endodontics, DAPM RV Dental College, Bengaluru, Karnataka 
560078 

4 Lecturer, Department of Conservative Dentistry and Endodontics, DAPM RV Dental College, Bengaluru, Karnataka 560078 

5 Reader, Department of Conservative Dentistry and Endodontics, DAPM RV Dental College, Bengaluru, Karnataka 560078 

Article Info: 
_____________________________________________ 
Article History: 

Received   29 May 2025     
Reviewed  16 June 2025 
Accepted   25 June 2025 
Published 15 Sep 2025 

_____________________________________________ 
Cite this article as:  

Gopal P, Rao HM, Prasad BSK, Umesh S, Shetty 
R, Instrument Retrieval in Endodontics: A 
Literature Review, Asian Journal of Dental 
and Health Sciences. 2025; 5(3):13-15 DOI: 
http://dx.doi.org/10.22270/ajdhs.v5i3.133 

__________________________________________________ 

*Address for Correspondence:   

Dr Pavithra Gopal, Post Graduate, MDS, 
Department of conservative dentistry and 
Endodontics, DAPM RV Dental College, 
Bengaluru, Karnataka 560078              

Abstract 
_________________________________________________________________________________________________________________ 

Instrument separation poses a notable challenge in endodontic therapy, with occurrence rates 
between 2% and 6%. While a separated instrument does not automatically equate to treatment 
failure, it can hinder complete debridement and obturation, which might result in bacterial survival 
and inflammatory responses. This review of the literature examines the various factors that 
contribute to instrument separation, including mechanical fatigue, instrument design, and clinical 
aspects such as canal curvature and operator experience and evaluates the current methods 
available for retrieving these instruments. These methods encompass mechanical techniques (e.g., 
ultrasonics, retrieval kits), chemical solutions (e.g., EDTA), and surgical procedures when non-
surgical methods are ineffective. Advances in technology, including improved magnification, 
ultrasonic devices, and platforms like Endo Rescue, have enhanced retrieval success rates. 
Additionally, bioceramic materials and CAD/CAM-assisted restorations provide better outcomes 
following retrieval. Nonetheless, challenges persist, including the risk of root perforation, tooth 
fractures, and the presence of retained fragments. The success of the retrieval process depends on 
the position and size of the fragment, the anatomy of the canal, and the clinician's expertise. 
Research indicates that the presence of a retained instrument may not significantly impact 
prognosis when apical periodontitis is absent, though outcomes worsen in cases with infection. 
Ultimately, the clinician’s expertise, proficiency, and the integration of modern tools are crucial for 
effective management. Ongoing research and continuous professional development are vital for 
enhancing retrieval methods and improving patient results in endodontics. 

Keywords:  Instrument separation, Endodontic complications, Fractured file removal, Ultrasonic 
retrieval, Nickel-titanium instruments, Root canal anatomy, Endodontic retreatment, Masserann kit 

 

Introduction 

Instrument retrieval is a critical aspect of endodontic 
treatment. The incidence of instrument separation can 
range from 2% to 6%, posing a significant challenge for 
endodontists. Successful retrieval of separated 
instruments is essential to ensure the continued success 
of root canal therapy and prevent complications 1 

When an instrument breaks during a cleaning and 
shaping procedure, the clinician must consider various 
factors, including the pulp status, root canal infection, 
anatomy, position, type of the fractured instrument, and 
potential damage to the tooth structure. The success of 
nonsurgical removal of a broken instrument depends on 
the canal anatomy, fragment location, length, diameter, 
curvature, accessibility, fragment location, and 
visualization. Approaches for managing the separated 
instrument include removal, bypassing, sealing the 

fragment within the root canal, or creating a true 
blockage.2 

While a broken instrument may not directly cause 
treatment failure, the fragment in the root canal can 
obstruct proper cleaning, shaping, and obturation of the 
root canal space, leading to the accumulation of bacteria 
and dentin debris, which leads to inflammation. 3 

Root canal treatment is a cornerstone of modern 
dentistry, aiming to preserve natural dentition. However, 
the inherent complexity of root canal anatomy and the 
delicate nature of endodontic instruments can lead to 
unforeseen complications, such as instrument 
separation. This literature review will comprehensively 
examine current knowledge and techniques pertaining to 
instrument retrieval in endodontics, encompassing the 
challenges, available methodologies, and their respective 
successes and limitations. 

 

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Pavithra Gopal et al.                                                                                                                  Asian Journal of Dental and Health Sciences. 2025; 5(3):13-15 

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Causes of Instrument Separation 

Instrument separation can occur due to various factors, 
including: 

• Mechanical Factors: Excessive force, improper use, 
and cyclic fatigue of endodontic instruments can lead 
to separation. Instruments may also separate due to 
torsional stress when the tip of the instrument binds 
in the canal while the shank continues to rotate. 

• Instrument Design: The design and material of 
endodontic instruments, such as nickel-titanium 
(NiTi) files, can influence their susceptibility to 
separation. NiTi instruments, while flexible, are more 
prone to cyclic fatigue compared to stainless steel 
instruments. 

• Clinical Factors: Root canal anatomy, curvature, and 
operator experience play a significant role in the 
likelihood of instrument separation. Complex root 
canal systems with severe curvatures increase the 
risk of instrument separation. 

Techniques for Instrument Retrieval 

Several techniques have been developed for the retrieval 
of separated instruments, including: 

Mechanical Methods: 

• Ultrasonic Devices: Ultrasonic tips can be used to 
create vibrations that help dislodge the separated 
instrument. The use of ultrasonics under 
magnification allows for precise and controlled 
removal of the separated fragment. 

• Specialized Retrieval Kits: Kits such as the 
Masserann kit and the IRS (Instrument Removal 
System) are designed specifically for instrument 
retrieval. These kits include various tools and devices 
that can be used to grasp and remove the separated 
instrument. 

Chemical Methods: 

• Although less commonly used, chemical agents can 
sometimes aid in the dissolution of separated 
instruments. For example, EDTA 
(ethylenediaminetetraacetic acid) can be used to 
soften dentin and facilitate the removal of the 
separated instrument. 

Surgical Methods: 

• In cases where mechanical and chemical methods fail, 
surgical approaches such as apicoectomy may be 
necessary to retrieve the separated instrument. This 
involves surgically accessing the root tip and 
removing the separated instrument through a 
retrograde approach. 

Advances in Technology 

Recent advancements in technology have significantly 
improved the success rates of instrument retrieval: 

1. Ultrasonics and Magnification: 

a) Ultrasonics: Ultrasonic devices have revolutionized 
instrument retrieval by generating high-frequency 

vibrations that help loosen the separated instrument 
from the canal walls. This facilitates its removal and 
reduces the risk of further iatrogenic damage. 

b) Magnification: The use of dental operating 
microscopes provides magnified views of the working 
field, enabling clinicians to visualize better the 
separated instrument, its orientation within the canal, 
and the surrounding anatomical structures. This 
enhanced visualization significantly improves the 
precision and effectiveness of retrieval attempts. 

2. New Devices and Techniques: 

a) Endo Rescue System: This innovative system utilizes 
a micro-motor with specialized retrieval tips to 
engage and remove broken instruments with minimal 
risk of further fracture or canal wall perforation. 

b) Bioceramic Materials: Bioceramic materials, such as 
Mineral Trioxide Aggregate (MTA), play a crucial role 
in sealing the root canal after instrument retrieval and 
promoting tissue healing. The MTA's excellent 
biocompatibility and sealing properties help prevent 
post-treatment complications, such as infection and 
microleakage. 

Additional Technological Advancements: 

Computer-Aided Design/Computer-Aided 
Manufacturing (CAD/CAM): CAD/CAM technology allows 
for the fabrication of customized posts and restorations, 
which can be particularly beneficial in cases where 
instrument retrieval has altered the root canal anatomy. 
The incorporation of advanced technologies has 
significantly enhanced the predictability and success of 
instrument retrieval in endodontics. By combining 
ultrasonic devices, magnification, innovative retrieval 
systems, and biocompatible materials, clinicians can 
address this challenging complication more effectively, 
improving patient outcomes and preserving natural 
dentition. 

Challenges and Complications 

Despite advancements, instrument retrieval remains 
challenging and can be associated with complications 
such as: 

• Root Perforation: The risk of perforating the root 
during retrieval attempts. This can compromise the 
structural integrity of the tooth and lead to treatment 
failure. 

• Tooth Fracture: The potential for tooth fracture due 
to excessive force or stress during retrieval. Careful 
and controlled techniques are essential to minimize 
this risk. 

• Residual Fragments: In some cases, small fragments 
of the separated instrument may remain in the root 
canal, posing a risk for future complications. 

Discussion 

Intracanal separation of instruments usually prevent 
access to the apex and impede thorough cleaning and 
shaping of the root canal, and thus may compromise the 



Pavithra Gopal et al.                                                                                                                  Asian Journal of Dental and Health Sciences. 2025; 5(3):13-15 

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outcome of endodontic treatment and reduce the chance 
of successful retreatment4 

The following factors influence the removal of detached 
instruments: the fragment's diameter, length, and 
location inside the canal. The circumferential diameter, 
thickness of the remaining dentin, and depth of an 
external concavity of the root determine the diameter, 
length, and curvature of the canal architecture. Generally, 
a stressed instrument such as when the flutes appear 
unwound, it is more likely to split in the canal and hence 
it is not recommended to press or wedge instruments No. 
8 and No. 10 within the canal; they should only be used 
once.  

Removal is not feasible if the broken instrument section 
is apical to the canal's curve and safe access cannot be 
obtained. If symptoms are present, surgery or extraction 
may be necessary.  

Files made of stainless steel are typically easier to 
remove since they don't break when being removed. 
During ultrasonic removal, the NiTi instrument can 
shatter again. Hence, the most crucial element for a 
successful instrument removal is knowledge, training, 
and ability.  

According to YaShen et al., the tooth's curve influences 
how the separated instrument is removed.5 Hulsmann et 
al. discovered that the shattered instrument was easiest 
to remove from the coronal third and had the lowest 
success rate in the apical third.6 In curved canals, Souter 
et al. demonstrated a reduced success rate when 
removing an instrument from the apical third.7 

Fors and Berg concluded that separated instruments in 
the apical third should remain in place, as removal 
attempts could cause perforation, which would worsen 
the prognosis of the endodontic treatment. The canal can 
be prepared and filled to the point where 
instrumentation is possible if the fragment cannot be 
retrieved.  Apical surgery is not required as long as the 
tool fragment is not sticking through the apex. The 
remaining tooth structure shouldn't be weakened by 
removing the detached portion. 

Several general outcome studies have linked the success 
rate of endodontic therapy with the presence or absence 
of Apical periodontitis.8,9,10 A new meta-analysis and 
systematic review examined the endodontic results of 
keeping an instrument in the root canal system.11 The 
prognosis of endodontic therapy in the absence of apical 
periodontitis is not considerably lowered by a retained 
fractured tool; nevertheless, in the presence of apical 
periodontitis, the prognosis is lowered by a fractured 
instrument. This review solely considered de novo cases. 
Notably, it was proposed that, as long as the treatment 
was performed to the most superb technical standard, a 
fractured file would have little effect on canal 
disinfection. 

Conclusion 

Instrument retrieval is a vital component of endodontic 
treatment, and advancements in technology have 

significantly improved success rates. However, 
challenges and complications still exist, and further 
research is needed to develop more effective and less 
invasive retrieval techniques. Continued education and 
training for endodontists are essential to ensure the 
successful management of separated instruments. 

Conflict of interest: No potential conflict of interest 
relevant to this article was reported. 

Author Contributions: All authors have equal 

contributions in the preparation of the manuscript. 

Source of Support: Nil 

Funding: Nil. 

Informed Consent Statement: Not applicable.  

Ethical approval: Not applicable. 

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https://doi.org/10.1097/00004770-200006000-00014
https://doi.org/10.1111/j.1600-9657.1993.tb00278.x
https://doi.org/10.1016/S0099-2399(06)80062-2
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