A patient with a history of poor oral health visited his dentist after an interval of five years, complaining of pain in the lower left quadrant. Bitewing radiographs revealed a large occlusal radiolucency at LL6 characteristic of a cavity encroaching the pulp, and the dentist advised the patient that root canal treatment might be necessary.

The following week, the dentist dressed and restored the tooth with an amalgam filling. No pulp exposure was observed but the dentist warned the patient that if tooth became sensitive he would need root canal treatment.

Before his next check-up was due, the patient attended a weekend access centre in severe pain where he was seen by a different dentist. It was noted that LL6 was very tender with buccal swelling and cheek bruising. After opening up the tooth, the dentist disinfected three root canals and provided a temporary filling. The patient was prescribed antibiotics and advised to return to his usual dentist for further treatment.

At this review appointment, the LL6 remained tender to percussion and the patient opted for root canal treatment.

When the patient returned for the procedure, the dentist recorded an estimated working length of 20mm. However, after taking a periapical radiograph, he noted the three endodontic instruments were 4-5mm short of the radiographic apex and increased the working length to 22mm. The radiograph also showed periapical radiolucency characteristic of chronic infection around the mesial root.

During the procedure, an endodontic file broke and a 4mm section was retained in the mesio-buccal canal. The dentist did not record how the fracture happened, although he informed the patient and advised him that the tooth would need to be monitored over the long term. The dentist completed the procedure with the patient's consent.

Soon afterwards, the patient returned because the LL6 tooth had fractured and was causing him severe pain. This time, it was agreed that tooth could not be saved and it was agreed the dentist would make a referral for extraction because the tooth's curved roots made the procedure more complicated.

The extraction was carried out successfully 10 days later when it was discovered the broken endodontic file had penetrated 2mm through the apex of the mesio-buccal root.

The patient later made a claim against the dentist, alleging that the root canal treatment had been negligently carried out and that the dentist had missed earlier opportunities to diagnose and treat the tooth.

The DDU sought the opinion of an expert GDP witness who was critical of the dentist's treatment, believing it fell below an appropriate clinical standard. In particular, the expert was critical that a post-operative radiograph was not taken and of the dentist’s failure to clean, shape and obturate the root canal system.

With the member's agreement, the DDU offered to settle the claim and the claimant accepted £6,000 in compensation.