Review Article
Management of Intracanal Separated Instruments

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Abstract

Introduction

Intracanal separation of endodontic instruments may hinder cleaning and shaping procedures within the root canal system, with a potential impact on the outcome of treatment. The purposes of this narrative review of separated instruments were to (1) review the literature regarding treatment options, influencing factors, and complications and (2) suggest a decision-making process for their management.

Methods

An online search was conducted in peer-review journals listed in PubMed to retrieve clinical and experimental studies, case reports, and review articles by using the following key words: instruments, files, obstructions, fractured, separated, broken, removal, retrieval, management, bypassing, and complications with or without root canal and endodontic.

Results

There is a lack of high-level evidence on management of separated instruments. Conventional conservative management includes removal of or bypassing the fragment or filling the root canal system to the coronal level of the fragment. A surgical intervention remains an alternative approach. These approaches are influenced by a number of factors and may be associated with complications. On the basis of current clinical evidence, a decision-making process for management is suggested.

Conclusions

Guidelines for management of intracanal separated instruments have not been formulated. Decisions on management should consider the following: (1) the constraints of the root canal accommodating the fragment, (2) the stage of root canal preparation at which the instrument separated, (3) the expertise of the clinician, (4) the armamentaria available, (5) the potential complications of the treatment approach adopted, and (6) the strategic importance of the tooth involved and the presence/or absence of periapical pathosis. Clinical experience and understanding of these influencing factors as well as the ability to make a balanced decision are essential.

Section snippets

Impact of Retained Separated Instruments on Root Canal Treatment Outcome

When an instrument separates in a root canal system, 2 main concerns need to be addressed to maximize the long-term treatment outcome. The first is the existence of a metal fragment inside the tooth and the possibility of corrosion. The only available report concluded that SS fragments were inert and did not exhibit corrosion after 2 years (21). Future studies in this area on both SS and NiTi instruments are of great importance. The other main concern is that a separated instrument usually

Management Options

Management of separated instruments includes orthograde or surgical approaches. Orthograde approaches are as follows 27, 28: attempts to remove the fragment, attempts to bypass the fragment, or cleaning/shaping and filling of the root canal to the level of the fragment.

In general, it would seem appropriate that the optimum management option was removal of the fragment so that cleaning and shaping of the root canal system could be completed effectively to eliminate microorganisms. Such an

Tooth Factors

Tooth factors largely include anatomic factors that are dictated by the type of tooth, the cross-sectional shape and diameter of the root canal, position of the fragment within the root canal, location of the fragment with regard to root canal curvature, as well as the radius and degree of root canal curvature. Removal of separated instruments is more predictable in the following situations:

  • 1.

    In maxillary teeth 10, 29

  • 2.

    In anterior teeth 10, 29, 30

  • 3.

    When the fragment extends into the coronal third of

Techniques Used for Removing the Separated Instrument

Variations in success rates have been reported according to devices, techniques, methods, and protocols used for removal of separated instruments. Before a clinician makes the decision to remove a separated fragment, he/she should ensure the availability of and successful manipulation of the required materials, instruments, and devices. Each individual case has its own unique characteristics that will dictate the approach taken to manage the case. However, a clinician infrequently might be

Complications Associated with Removal of Separated Instruments

A variety of complications may be associated with removal of separated instruments 10, 29, 31, 42, 52, 71, 73. Ledge formation is common and usually prevents preparing and filling root canal system to the desired length (31). Ledges are also potential areas of stress concentration that may contribute to vertical root fracture (71). With the aid of magnification, ledges can be reduced or even removed by inserting a rotary file with greater taper or a precurved hand file and applying an axial

Bypassing the Separated Instrument

The ultimate goal of management of separated instruments is not only to retrieve the fragment but also to preserve the integrity of the tooth. With the associated complications, bypassing a fragment located deep in the root canal or beyond the root canal curvature, if possible, may be the appropriate treatment option. To some extent, this fulfills the objective of root canal treatment: proper cleaning and shaping of the root canal system followed by good filling. Thus, bypassing the separated

Leaving the Fragment In Situ

If a separated instrument cannot be removed or bypassed, referral of the patient to a specialist who is more experienced and equipped to handle such cases is generally the preferred option. Otherwise, cleaning, shaping, and filling the root canal system to the level of the fragment are the only alternative conservative approach. This may be especially applicable if the separation occurs toward the final stages of root canal preparation or the fragment is located in the apical third beyond a

Surgical Management of Separated Instruments

When conservative management of a separated instrument fails and clinical and/or radiographic follow-up indicates presence of disease, surgical intervention may be warranted if the tooth is to be retained. In addition, because of the evidence of adverse impact of periapical lesions on root canal treatment outcome, a surgical approach can be considered as the optimum management choice if the fragment is inaccessible and a periapical lesion is present at the time of instrument separation.

Summary

Guidelines for management of intracanal separated instruments should be based on the highest level of clinical evidence; however, this has yet to be formulated. The decision on management should consider the following: constraints of the root canal accommodating the fragment, the stage of root canal instrumentation at which the instrument separated, the expertise of the clinician, armamentaria available, possible associated complications, the strategic importance of the tooth involved, and the

Acknowledgments

The authors thank Dr Muhammad Hammad (Jordan University, Jordan) and Dr Alison Qualtrough (University of Manchester, United Kingdom) for their help and advice.

The authors deny any conflicts of interest related to this study.

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