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Year : 2022  |  Volume : 25  |  Issue : 1  |  Page : 105-108
Cyclic and spontaneous movement of a fractured and extruded instrument back into the root canal: A rare case report

1 Department of Conservative and Endodontics, K. M Shah Dental College and Hospital, Munjmahuda, Vadodara, Gujarat, India
2 Department of Conservative and Endodontics, Manubhai Patel Dental College and Dental Hospital, Munjmahuda, Vadodara, Gujarat, India

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Date of Submission08-Jun-2021
Date of Decision31-Oct-2021
Date of Acceptance01-Nov-2021
Date of Web Publication02-May-2022


Retreatment of endodontically involved teeth may require the removal of obstruction from root canal space. Instrument fracture is an undesirable and stressful incident which can negatively affect the prognosis of the tooth. Any corrective step taken should be performed with utmost care to prevent extrusion of the fragment into periapex. This case report describes a rare occurrence of movement of a fractured instrument during inter-appointment period. A previously treated left mandibular first molar with a fractured instrument was taken up for retreatment. During the course of treatment, the fractured fragment which was previously located in the apical third of the distal canal was dislodged into the periapical region. However, it was found that fragment moved back inside the canal after the inter-appointment period. The same sequence of events repeated before the instrument could be retrieved. Hydrostatic and vascular pressure build due to periapical inflammation could be cited reasons for such a movement.

Keywords: Fractured instrument; inflammation; movement; periapical; retreatment

How to cite this article:
Hirani AJ, Arora A, Hadwani KD, Cherian A. Cyclic and spontaneous movement of a fractured and extruded instrument back into the root canal: A rare case report. J Conserv Dent 2022;25:105-8

How to cite this URL:
Hirani AJ, Arora A, Hadwani KD, Cherian A. Cyclic and spontaneous movement of a fractured and extruded instrument back into the root canal: A rare case report. J Conserv Dent [serial online] 2022 [cited 2022 Aug 18];25:105-8. Available from:

   Introduction Top

Retreatment of endodontically treated teeth may require the removal of an obstruction from the root canal space. Instrument fracture is an undesirable and stressful incident that leads to psychological distress to practitioners as well as patients.[1] It can happen even to experienced clinicians if appropriate preventive measures are not followed.

The reported prevalence of retained fractured instruments ranges between 0.7% to 7.4% in teeth undergoing root canal treatment.[2],[3],[4] Instrument separation can occur at different levels along the length of the canal, but the incidence in the apical third beyond the curvature is 33 times greater compared to the coronal third and almost six times when compared to the middle third of the root canal.[5]

The separated file fragment is often engaged and firmly held inside the root canal wall. However, it is not uncommon to encounter a loose fragment, especially after gutta-percha (GP) removal or use of ultrasonics in a canal with a fractured instrument. In rare cases, it can get displaced into sinus or nerve canals during vigorous attempts to remove the same.[5] However, the reverse migration of a fractured instrument from the periapical region into the root canal has never been reported.

This case report describes a rare case of migration of separated instrument. During the course of treatment, the broken fragment oscillated twice between the canal and the periapex during inter-appointment periods.

   Case Report Top

A 37-year-old female patient presented to the department of conservative dentistry and endodontics with pain on mastication in the lower left back tooth region for the past 2 months.

The patient reported with a history of root canal treatment performed 6 months earlier. Extraoral examination showed no remarkable findings. Intraoral examination revealed tooth no. 36 had a temporary restoration and it was tender on percussion. Intraoral periapical (IOPA) radiograph revealed under-obturated both canals [Figure 1]a and [Figure 1]b.
Figure 1: (a) Preoperative clinical picture (b) Preoperative intraoral periapical radiograph irt 36 showing under-obturated canals with separated instrument at the apical third; (c) Displaced broken file extending 3 mm beyond apex; (d) CBCT depicting fractured file fragment in the coronal section; (e) Fractured fragment 2.14 mm beyond apex; (f) Broken file fragment back within the root canal

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Furthermore, the distal canal showed separated instrument extending 1 mm beyond the apex with diffuse periapical radiolucency around it. Based on clinical and radiographic findings, a diagnosis of previously treated tooth with chronic apical periodontitis in relation to 36 was formulated. It was planned to retrieve the instrument considering it as one of the etiological factors for persisting disease. The patient was informed about the treatment procedure and informed consent form from the patient was taken. Local anesthesia (LA) (Lignox, Indoco Remedies Ltd., Warren Pharma, Mumbai, Maharashtra, India) was administered as the patient reported with pain, the tooth was tender to percussion and even the rubber dam application occasionally leads to discomfort due to impingement of the prongs. Hence, to avoid any pain to the patient during instrumentation and alleviate the patient anxiety, LA was administered. As a part of emergency treatment, old restoration was removed, three orifices were located, and GP was removed from all the canals using H-files (Mani, INC., Japan) in the same appointment. Extreme care was taken not to disturb the broken file. IOPA was taken to confirm the removal of GP. It was observed that GP was removed but the separated instrument was displaced further, around 3 mm beyond the apex [Figure 1]c. No further attempt was made to remove the file and the patient was prescribed anti-inflammatory drugs and was recalled after 2–3 days.

As the patient reported back with persistent pain, cone-beam computed tomography (CBCT) scan and mandatory blood investigations were advised for the patient to plan the removal of the fractured file surgically. Fractured fragment measured 2.14 mm in length in the sagittal view of CBCT [Figure 1]d and [Figure 1]e. A day before surgery, IOPA was taken as per the protocol. To our surprise, separated instrument's radio-opacity was observed within the confines of the canal in the middle third [Figure 1]f. Two angulated radiographs at different horizontal angulation were taken to rule out any error in position.

Considering the position of the file, it was deemed necessary to attempt its removal nonsurgically. Build-up of the missing distal wall was done using composite resin (Tokuyama Dental Deutschland, GmbH, Altenberge, Germany). After bypassing the fragment with #10 and #15 K file (Mani, INC., Japan), attempt was made to dislodge it out of the canal using vigorous irrigation with saline, H file (Mani, INC. Japan) and the use of ultrasonics under magnification (Labomed Prima DNT, Labomed India, Bangaluru). Unfortunately, within the recommended time frame of 45 min, none of techniques worked and we could only manage to loosen the fragment.[6],[7] Further attempt led to the displacement of the file back into the periapical region [Figure 2]a.
Figure 2: (a) Displacement of the file again into the periapical region; (b) Broken file back inside the canal again; (c) Retrieved instrument; (d) Confirmatory IOPA after file retrieval; (e) Post-obturation IOPA; (f) Follow up IOPA at 2 years

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Assuming that the instrument was mobile in a rare interconnection between the root canal and the periapical region, the patient was recalled after a week again with the hope that it would migrate back like it did before. IOPA revealed the surprising movement of the file fragment back up to the middle third of root canal [Figure 2]b.

As a final attempt, extreme precautions were taken this time to retrieve the instrument. Coronal flaring of the distal canal was done using GG drills no. 1 and 2 (Mani, INC., Japan) for improved visibility, thereby creating space for the fragment to move coronally. Vigorous saline irrigation was performed initially using #30-gauge side vented needle (Neo-Endo, Orikam Dental Pvt. Ltd., India) with its end placed apical to the fragment end.

Ultrasonic tips (IR2; IR3 Retrieval tips, Cric Dental, Mumbai) were then used to remove any interfering coronal root dentin and loosen the fragment on a power setting of 3. The fractured file fragment popped out on when the canal was irrigated again with saline. Periapical radiograph was taken postoperatively for confirmation of file retrieval [Figure 2]c and [Figure 2]d. Biomechanical preparation was completed in the same visit and calcium hydroxide dressing (Prime Dental RC Cal, Prime Dental Products, Mumbai, Maharashtra, India) was placed for 2 weeks.

In the subsequent visit, obturation was done with GP and AH plus sealer (Dentsply Maiellefer, Tulsa, Oklahoma, USA) using cold lateral compaction technique [Figure 2]e. Post-endodontic restoration was done using packable composite (Tokuyama Dental Deutschland, GmbH, Altenberge, Germany) after sealing the orifices using flowable composite. After the removal of rubber dam, final occlusion was checked and adjusted. Finishing and polishing of restoration were done using composite finishing and polishing kit (Shofu, Super-Snap Rainbow Kit, Shofu Dental Corporation, USA). The patient did not report for prosthetic rehabilitation further and was not available for follow-up due to COVID restrictions. The patient reported no complaints with regard to the same tooth telephonically. The patient came for follow-up directly after 2 years. Radiograph shows complete periapical healing is seen in relation to both the roots [Figure 2]f.

   Discussion Top

Separation of endodontic instruments within the root canal is an unfortunate occurrence that may hinder root canal procedures and affect the outcome.[8] With the increased use of rotary Nickel − Titanium rotary files, there has been an increased prevalence (0.4%–5%) of fractured instruments due to their low yield strength and tensile strength as compared to stainless steel files.[3],[4]

The decision on the management of fractured instruments is generally based on the constraints of the root canal accommodating the fragment, the stage of root canal instrumentation, the expertise of the clinician, armamentarium available, the strategic importance of the tooth involved, the presence or absence of periapical pathosis, and associated complications.[2],[8] In the present case, the decision to retrieve the instrument was taken as the instrument was interfering in complete debridement of the apical part of the distal canal which had a periapical lesion.

Majority of instrument fracture occurs in the apical third of the root canal as was seen in this case.[9]

Retreatment was justified in the present case as the patient was symptomatic, temporary restoration was fractured, microleakage around the restoration was evident, and a fractured instrument was seen radiographically in the distal root which also had a periapical lesion. In the emergency visit, GP was removed with the aim of relieving the patient of the pain. H-files were used to remove the GP as they are rigid and their flutes easily engage the GP allowing effortless removal with slight clockwise motion.[8]

In the present case, even after taking precautions to avoid disturbing the fractured file, it moved into the periapex. The broken file was probably loose and only held by GP. Removal of GP with H-file would have let the file free. Furthermore, the contact of the fractured fragment with the H-file would have pushed it beyond the apex.

Any instrument which is pushed beyond the apex needs to be removed if the symptoms of disease and pain persist.[10] In the above case, the patient was symptomatic and the success with nonsurgical technique for the removal of fractured instrument from the periapical region was unlikely without extensive dentin loss and weakening of tooth.[5] Hence, surgical removal of the instrument was planned.

A CBCT was required to plan for the surgical removal of the instrument.[11] In the present case, it helped in surgical treatment planning by assessing the exact dimensions and location of fractured file segment with respect to the root end and to determine the dimensions of the drill site. It also helped in the evaluation of the tooth morphology and proximity of the root end to the mandibular canal.

Coronal enlargement of distal canal was carried out for enhanced visibility, accessibility, and creating space for the fragment to move coronally.[1] Ultrasonic agitation with retrieval tips was done under 16 X magnification at a lower power setting. It is a less invasive procedure that delivers controlled vibrational motion at the interface of file and tooth and loosens file fragment leading to outward displacement or popping out of the separated file from the canal.[12]

Copious irrigation was performed with normal saline to remove root dentin debris and dentin chips to enhance visibility and facilitate the removal of loosened file from the canal.[13]

The above case is the first report of such an incident where a separated file fragment got dislodged twice into the periapex and moved back inside the canal up to the middle third, travelling distance of 4 mm against gravity. There are various assumptions for intra-appointment movement of the instrument in and out of the tooth. Irrigation and negative aspiration alone can move the fragment because of fluid dynamics.[14] Intracanal medicaments can lead to inadvertent movement of the file, especially in Vertucci type 2 canal configuration.

Inter-appointment movement of fractured instrument can be attributed only to gravity or force exerted by any inflammatory products. In the present case, the coronal movement of the fragment was observed twice in a short span of time. The gravitational pull can only lead to apical movement for a mandibular tooth, so the only practical explanation to the movement of the file could be a large communication between the periapex and the root canal and pressure generated by inflammatory products in the periapical region leading to movement of the file. Inflammation can lead to hydrostatic and vascular pressure build-up which can displace the file.[15]

   Conclusion Top

Instrument fracture is a complication in itself and any corrective steps taken should be performed with utmost care to prevent extrusion of the fragment into the periapex. Unexpected, spontaneous and favorable movement of the fractured fragment can occur rarely as was seen in the above case where periapical inflammation possibly proved to be a boon.

Declaration of patient consent

The authors certify that they had obtained all appropriate patient consent forms. In the form, the patient has given her consent for her images and other clinical information to be reported in the journal. The patient understands that her name and initial will not be published and due efforts will be made to conceal their identity, but anonymity cannot be guaranteed.

Financial support and sponsorship


Conflicts of interest

There are no conflicts of interest.

   References Top

Ruddle CJ. Nonsurgical retreatment. J Endod 2004;30:827-45.  Back to cited text no. 1
Spili P, Parashos P, Messer HH. The impact of instrument fracture on outcome of endodontic treatment. J Endod 2005;31:845-50.  Back to cited text no. 2
Khasnis SA, Kar PP, Kamal A, Patil JD. Rotary science and its impact on instrument separation: A focused review. J Conserv Dent 2018;21:116-24.  Back to cited text no. 3
[PUBMED]  [Full text]  
Parashos P, Messer HH. Rotary NiTi instrument fracture and its consequences. J Endod 2006;32:1031-43.  Back to cited text no. 4
Lambrianidis T. Management of Fractured Endodontic Instruments: A Clinical Guide. 1st ed. Cham: Springer; 2018.  Back to cited text no. 5
Suter B, Lussi A, Sequeira P. Probability of removing fractured instruments from root canals. Int Endod J 2005;38:112-23.  Back to cited text no. 6
Rhodes JS. Advanced Endodontics: Clinical Retreatment and Surgery. 1st ed. New York: CRC Press; 2005.  Back to cited text no. 7
Madarati AA, Hunter MJ, Dummer PM. Management of intracanal separated instruments. J Endod 2013;39:569-81.  Back to cited text no. 8
Tzanetakis GN, Kontakiotis EG, Maurikou DV, Marzelou MP. Prevalence and management of instrument fracture in the postgraduate endodontic program at the Dental School of Athens: A five-year retrospective clinical study. J Endod 2008;34:675-8.  Back to cited text no. 9
Pak JG, White SN. Pain prevalence and severity before, during, and after root canal treatment: A systematic review. J Endod 2011;37:429-38.  Back to cited text no. 10
Patel S, Dawood A, Ford TP, Whaites E. The potential applications of cone beam computed tomography in the management of endodontic problems. Int Endod J 2007;40:818-30.  Back to cited text no. 11
Fu M, Zhang Z, Hou B. Removal of broken files from root canals by using ultrasonic techniques combined with dental microscope: A retrospective analysis of treatment outcome. J Endod 2011;37:619-22.  Back to cited text no. 12
Haapasalo M, Shen Y, Qian W, Gao Y. Irrigation in endodontics. Dent Clin North Am 2010;54:291-312.  Back to cited text no. 13
Loroño G, Zaldivar JR, Arias A, Cisneros R, Dorado S, Jimenez-Octavio JR. Positive and negative pressure irrigation in oval root canals with apical ramifications: A computational fluid dynamics evaluation in micro-CT scanned real teeth. Int Endod J 2020;53:671-9.  Back to cited text no. 14
Mohan H, Mohan S. Essential Pathology for Dental Students. 4th ed. New Delhi, India: Jaypee Brothers Medical Publishers Ltd.; 2012.  Back to cited text no. 15

Correspondence Address:
Dr. Anoli Jagdishbhai Hirani
Department of Conservative and Endodontics, K. M Shah Dental College and Hospital, Piparia, Vadodara - 391 760, Gujarat
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Source of Support: None, Conflict of Interest: None

DOI: 10.4103/jcd.jcd_303_21

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