• Restoration with a crown.
• Periapical radiolucency.
• Separated instruments in disto-buccal and palatal canals.
• No evidence of root filling in mesio-buccal canal.
• Good marginal bone levels.

Diagnosis and treatment planning

The diagnosis is chronic periapical periodontitis associated with a root canal treated tooth.

What are the treatment options generally in cases with
separated instruments?

• No treatment.
• Non-surgical root canal re-treatment attempting to bypass or retrieve the instrument.
• Surgical treatment (periapical microsurgery).
• Extraction.

A surgical or non-surgical approach?

The decision to treat the case by a surgical or non-surgical approach depends on a combination of factors. The position of the separated file in the canal is important. If it is positioned at the apex or in the root curvature beyond the straight portion of the canal, it is unlikely to be removed by non-surgical treatment. However, this does not mean that the case should immediately be treated surgically. As a general rule, non-surgical re-treatment should always be completed first. In practical terms, if the instrument cannot be removed, and disease or symptoms persist after good quality root canal retreatment, a surgical approach can be considered.

Which devices are available to retrieve fractured instruments non-surgically?

• Ultrasonics. A range of lengths and sizes are available for controlled ‘troughing’ around the head of the fractured segment. Ultrasonics can also be used to vibrate and ‘unscrew’ the file from the canal wall. Drawbacks include the cost of the tips and the tendency to remove excess tooth substance.
• Holding devices (e.g. Masseran kit, Meitrac Endo Safety System). A range of drills trephine around the head of the separated instrument prior to a second instrument engaging the coronal aspect, hence allowing the instrument to be withdrawn for the canal. This technique is generally only possible when the separated instrument is in the middle or coronal aspects of straight canals, and invariably requires considerable dentine removal to be effective.

What are the treatment options in this case?

• No treatment.
• Extraction.
• Non-surgical root canal retreatment (attempting retrieval) followed by core build-up and cuspal coverage restoration.

The 16 was tender and recently had a ‘flare-up’. The patient found the tooth was painful during mastication and had been informed that there was a risk of another acute ‘flare-up’. Therefore, he did not wish to leave the tooth untreated. The crown was marginally defective and there was decay present mesially; however, it was not possible to decide whether the tooth was restorable without removing the crown first.

The patient was informed of this uncertainty and asked if he wished to proceed on the understanding that restorability could not be guaranteed and the tooth may need to be extracted. The periodontal condition around the 16 was satisfactory and the tooth was in occlusion with the mandibular second premolar and first molar. If the fractured files could be successfully removed, there would be an anticipated good outcome. Extraction would have resulted in an increased edentulous area as tooth 15 had already been extracted some years previously. Therefore, the decision was made to investigate the 16 initially and, if restorable, proceed with root canal re-treatment.

What advice should be given to the patient prior to treatment?

• Advise that the restorability of the tooth is questionable and will need to be verified.
• Inform the patient that there is more than one separated instrument in the root canals.
• Explain to the patient that the instruments are not the source of infection, rather an obstruction preventing proper disinfection of the canals.
• Suggest that it may not be possible to remove the fragments and give options if unsuccessful.

Treatment

Removal of crown and investigation

The crown was easily removed using an excavator and gentle pressure palatally. Afterwards, the tooth was isolated with rubber dam, and a sealing material was used to provide further resistance to the ingress of saliva. Decay was present mesially and this was removed using a round bur in a slow handpiece. The tooth was examined and found to be restorable, with sufficient coronal tooth substance remaining.

Removal of fractured instruments

The pulp chamber was ultrasonically cleaned and the anatomy explored. Using the operating microscope, Gates Glidden burs and ultrasonic tips were used to create a small ‘staging platform’ above the head of the fractured files, first in the palatal root, and afterwards in the disto-buccal root. The heads of the separated instruments could now be visualized with the microscope. The canals were gently negotiated with hand files to assess the possibility of bypassing the separated instruments; this was not successful. Thereafter, using long ultrasonics (Figure 5.5.2

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