Fig. 1

Figure 1

37 year-old female patient with non-contributory medical history was referred for root canal retreatment of tooth 46.

Dental records report acute pain and swelling on right lower jaw 3 months ago, for which Amoxicillin (1gr per 12 hours for 1 week) was prescribed by her dentist. Since then no other major pain incident reported aside for slight sensitivity on percussion. Initial radiograph (Figure 1) suggests a large periradicular lesion related to the distal root apex. Two fragments of endodontic files are evident in the mesiobuccal root canal, and one small fragment in the distal root possibly located into an apical split.

After inferior alveolar nerve block with mepivacaine, the tooth was isolated and careful removal of the occlusal composite filling was performed until gutta-percha was revealed in the three root canal orifices (mesiobuccal, mesiolingual, distal).

Mesiobuccal root canal was already enlarged, possibly in an attempt to remove the fragments. Ultrasonic tip ET20 (Satelec, Acteon Group, France) was used to remove lingual dentine overhangs, so as to obtain an improved visualization of the coronal stainless steel fragment. The fragment was then gradually released and removed, using the ultrasonics in a counterclockwise motion.

The same tip was used to release the coronal 2mm of the apically broken Niti file. Because those files are prone to fracture at the point of contact with the ultrasonic vibration, it is vital to avoid constant touch of the coronal part of the fragment and use a lower power mode during dentine removal at the circumference. In addition, it is preferable to use a grasping tool when the right time comes. In this case, EndoCowboy  (Köhrer Medical Engineering GmbH, Germany) was used with a 0.12 lasso tip to grab and retrieve this fragment.

Fig. 2

Figure 2 shows the cone fitting after removal of instruments in the mesiobuccal root canal. A fragment of small size probably 8 or 10 is evident in the mesiolingual canal at the apical third, which has been by-passed by the cone. 

Cone fitting is still not ideal and in the distal root canal the guttaperhca cone is short of the apex, despite the fact that the apex locator (ipex II, NSK, NAKANISHI INC, Japan) gave signal at this point, possibly due to the apically located small metallic fragment distal to the main canal.

Fig. 3

Figure 3

At this point, final obturation of the mesial root canals with warm vertical compaction technique and AH plus sealer was performed, while in the distal root canal the apical fragment is clearly depicted.

With an ultrasonic tip enlargement of the distal root canal to a lingual direction was carefully done and the coronal tip of the instrument became evident. To avoid further enlargement of the distal canal an XP-endo Finisher (FKG Dentaire, Switzerland) at 1000 rpm speed was used at working length with small coronally directed strokes.

Fig. 4

Figure 4

The fragment was finally dislodged and removed. At this point, obturation of the mesiolingual canal was revisited due to some voids and cone fitting for the distal canal was checked. 

In an attempt to compensate for the pre-existing loss of dentin, the middle and coronal part of the mesiobuccal canal were filled with Biodentine (Septodont, France), which has mechanical properties close to human dentin.

Cones in the distal root canal slightly extruded working length and were adapted accordingly.

Fig. 5

Figure 5 

Final obturation of the distal canal and deep split was performed with Ah plus sealer and WVC technique. 

A small piece of Teflon tape was placed just over the floor and the orifices and temporary restoration with Cavit G was done. 

Fig. 6

About the author:

Dr Eleni Protogerou

Endodontist with expertise in orofacial pain differential diagnosis, root canal treatment and traumatic dental injuries. Bringing 11 years of comprehensive experience determining causes, prevention and treatment of diseases and injuries related to teeth's dental pulp. Valued by patients for promoting good dental hygiene through continuous education and encouragement of preventive maintenance measures. Certified in Endodontics.


Many factors influence successful fragment removal such as operator judgment, training, experience, and utilizing the best technologies and techniques. Knowledge and respect for the anatomy of teeth and familiarization with the typical range of variation associated with each tooth type are essential. 

The clinician must keep in mind that fragment removal is just a medium for better disinfection and not an end in itself. The main goal of endodontic treatment of non- vital or revision cases remains to reduce the microbial load to a specific threshold at which the body's immune system can initiate healing. The ultimate goal is to give the treated tooth longevity and boost its survival in a healthy state. 

If fragment removal risks to compromise this goal then alternative, more conservative, approaches should be considered.


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. 2022 May:55 Suppl 3:685-709.