History

The patient complained of pain in the UL4 and UL5 area. The dentist noted that these teeth were tender to percussion and that they tested positive for signs of pulpitis. Periapical radiographs were obtained, and the dentist noted that these showed recurrent caries under the UL5 crown and periapical pathology in relation to UL4. She started root canal treatment on both teeth.

A few days later, the patient visited an emergency dentist complaining of acute pain. Radiographs showed fractured instruments in both teeth and the emergency dentist opened both root canal systems, cleaned them and left them open to drain. He prescribed antibiotics and analgesics.

The patient consulted a specialist in endodontics. He obtained radiographs, which confirmed the presence of fractured instruments. He advised that root canal treatment be continued, but also warned that there was a reduced prognosis for the teeth and that apicectomy and retrograde seal might be required in the future.
The patient went back to his dentist several times for the completion of the root canal treatment. The fractured instrument in UL4 was successfully by-passed, and the one in UL5 was left in place. During this time, it was noted that the palatal cusp of UL4 had fractured sub-gingivally and this cusp was removed. Preparations were made for the construction of a cast post and diaphragm core and a porcelain fused to metal crown for UL4. The crown was fitted without any complication being noted. (No radiograph was obtained.)

The patient did not visit his dentist again after this treatment. However, a year later, he visited another dentist, with whom he had been registered three years previously. This dentist noted that the post in UL4 had perforated the root canal system, and also that the root filling was through the apex. He noted that both UL4 and UL5 had apical areas and there was an area associated with the perforation. This dentist performed apicectomy and retrograde root filling of UL4 and UL5, and a perforation repair of UL4. He told the patient that both these teeth had a poor prognosis and he would probably need dental implants.

Negligence alleged

It was alleged that the dentist had carried out unnecessary root canal treatment on both teeth, and had done so negligently. Instruments had broken and been left in the root canals, and the post in UL4 had perforated through the side of the root.

Expert opinion

The DDU approached a consultant in restorative dentistry. He looked at the periapical radiographs of UL4 and UL5, taken by the dentist before she began the root canal treatment. The expert agreed there was evidence of recurrent caries under the UL5 crown, but did not endorse the dentist's findings in relation to UL4.
He said the dentist should initially have treated just the UL5:

"The diagnosis of pulpitis is usually straightforward ...However, the identification of the offending tooth can be exceedingly difficult, due to the lack of mechano-receptors in the dental pulp. (The dentist) seems to have relied on tenderness to palpation and radiographic changes, neither of which are appropriate tests. It is also extremely rare that two adjacent teeth would become pulpitic at the same time...Her lack of application of thermal tests and electronic pulp testing could be open to criticism..."

He denied that the broken instruments were proof of negligence, and said there was no evidence that these fractures had damaged either of the teeth:

"A fracture of fine endodontic instruments inside root canals is a well known complication of endodontic therapy ...However, the fact that (the dentist) was unaware that this had happened gives cause for concern..."

He considered the claim by the second dentist that he had been presented with a perforation of the post in the UL4. Having studied an undated radiograph supplied by this dentist, he concluded :

"...it does show a deviation from the root canal system of a serrated post, as well as a distal radiolucency, which is consistent with a perforation but would also be consistent with a root fracture which may have occurred subsequent to the post being placed ... I can see no independent conclusive evidence that there was a perforation, although clearly there is some morbidity associated with the root".

Outcome

It was felt that the dentist's diagnosis and treatment plan were vulnerable to criticism. She agreed that the patient should be offered an out-of-court settlement. The patient accepted £10,000.

Risk management advice

Before embarking on any root canal therapy it is essential to obtain a full history, and to carry out appropriate special tests, including vitality tests and radiographs. These should be clearly recorded in the clinical notes, so that you are in a position to demonstrate that root canal treatment was appropriate

The patient should be given clear and comprehensive explanations, in laymen's terms, of what is involved in root canal therapy, of the significant complications, the chances of success, and the alternatives

The fracture of an endodontic instrument, leaving a portion in situ, is not of itself negligent. However, to successfully resist an allegation of negligence, the instrument must have been in good condition, the complication must be recognised, the patient must be informed of the complication, and appropriate arrangements must be made to remedy or review the situation. Again, all these actions should be clearly recorded in the clinical notes, including the fact that the patient has been informed of the complication

Patients are entitled to a second opinion, and if the patient asks for one, or specialist advice/treatment is appropriate, the dentist is obliged to refer the patient

Fractured instruments

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