Treatment of fine canals

canal painDickon Adams presents a case study focusing on severe pain in the UL6.

Patient complaint

The 43-year-old patient attended with severe pain in her upper left quadrant.

UL6 had been found to be tender and a diagnosis of acute apical periodontitis was made. The patient reported that her bridge had been placed a few years previously.


The previous examination had revealed a diagnosis of acute periapical periodontitis in the UL6.

The options presented to the patient were extraction. Also, possible replacement with an implant, removal of the bridge and root canal treatment or root canal treatment through the bridge.

As the bridge was relatively new, the patient opted for root canal treatment through the bridge. The radiographs (Figure 1) gave a suggestion of distal caries. Although, it was not possible to identify any issue around the margin of the abutment crown.

Figure 1: Preoperative radiograph showing widening of periodontal ligament space


The root canals were accessed through the metal ceramic crown. The canals were extremely fine and required size six C files to reach the apical foramen. The canals were then widened with hand files to a size 20.

A Hyflex EDM 25/~ niti file (Coltene) was used to within about 4mm of the working length. It was not possible to instrument to the full working length with the EDM 25/~ file in view of the tightness of the canals.

Consequently, the apical section was instrumented first with a Hyflex EDM glide file (10/0.05) prior to completion of instrumentation with a Hyflex EDM 25/~. This ensured a much-reduced likelihood of fracture of the 25/~ file.

A second mesio-buccal canal was located midway between the MB1 and palatal openings. It appeared to be separate to the MB1 canal. This was filed in a similar fashion, although the working length was somewhat shorter.

The canals were irrigated with a combination of 2% sodium hypochlorite (NaOCl) and ultrasonics, with patency maintained throughout, before final irrigation with ethylenediaminetetraacetic acid (EDTA), ultrasonics and NaOCl.

Finally, EDM 25/~ gutta percha (GP) points were sealed with Bioroot root canal sealer (Figure 2). The GP points were cut off near to the canal orifice with a dry ultrasonic scaling tip and compressed into the top of the canal to ensure a good seal.

Figure 2: Following obturation. Note the curvature of the canals has been retained

Treatment outcome

Due to the controlled memory effect of the Hyflex files, I was able to accurately and safely follow the anatomy of all canals, reducing the risk of ledging, transportation and perforation. This in turn, helped to maintain the anatomy and patency of the root canal system and not over prepare the apical sections, as seen in the final radiograph.

The patient reported little discomfort following the procedure and the tooth has remained symptom free.

This article first appeared in Endodontic Practice magazine.

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