In 2014/15, over 5.6 million NHS dental patients received root canal treatment in England, although many more would have received the treatment privately. The British Endodontic Society (BES) suggests the treatment has a success rate of 90% if it is carried out to a good standard, which means there would have been a positive outcome for most of these patients.

At the same time, root canal procedures demand a higher level of technical skill than many other dental restorations and there are a range of risk factors to be considered as part of any pre-treatment assessment (see box - A specialist's perspective).

In short, endodontic procedures are risky and a miscalculation can prove costly. Root canal treatment featured in 1,429 dental claims notified between 2005 and 2014, which was 23% of the total. And there was a clear upwards trend; the number of claims in the second half of the period was 42% higher than in the first five years (838 compared with 591).

Cost and compensation

Endodontics claims also proved significantly harder to defend successfully, with 62% of claims settled between 2005 and 2014, compared with 46% where other types of treatment were involved.

Compensation awards tended to be lower than for claims involving other types of treatment, reflecting the fact that the treated teeth were already compromised. The average compensation payment was £5,112 for endodontic cases, compared with £13,397 for settled periodontal claims.

The highest amount awarded in an endodontic compensation was £65,000 plus costs, although substandard root canal treatment was one of several allegations made by the claimant, who lost several teeth. Where the allegations were solely about root canal treatment, the highest compensation award was £25,000 for a claimant who was left with persistent numbness and tingling in the lip.

Root cause

To get an insight into the most common reasons for endodontic claims, we reviewed 155 claims settled in 2013 and 2014. The most common primary reasons for claims were as follows:

No. of claims Reason
50 'Unsatisfactory' treatment (including other procedures)
35 Failed/inadequate endodontic treatment
18 Post-treatment complications: infection, persistent pain and fractured teeth
14 Fractured and/or retained instrument
14 Adverse incidents during treatment, e.g. burn to lip, swallowed instrument
13 Poor management, including failure to take radiographs or refer appropriately
8 Perforation
3 Valid consent not obtained

The most common settled claims involved patients who alleged their overall treatment was 'unsatisfactory' after having a number of different procedures, including root canal treatment. Unfortunately, it's not uncommon for claimants to make several allegations to strengthen their claim. From a dentist's perspective, it highlights the importance of a clear written treatment plan for patients with multiple dental problems which can be reviewed if the treatment doesn't produce results within the expected time.

Allegations of inadequate or failed treatment were common and in these cases the patient was obliged to have further root canal treatment, usually from a specialist, or have the tooth extracted. There's no guarantee that endodontic treatment will be successful, but a settled claim is more likely if the dentist's records don't show that a thorough pre-treatment assessment was undertaken. This would usually include relevant history, radiographs and recorded findings, as well as vitality tests.

A specialist's perspective

The variables in root canal treatment make it technically challenging and mistakes can be difficult to rectify, explains endodontist Howard Lloyd.

'General dental practitioners can put be in an impossible position, because patients aren't prepared to pay more for specialist endodontic treatment and pressure them to undertake the procedure. Sometimes patients are referred to me after their own dentist has started treatment and run into difficulties, but once something has gone wrong it can be difficult to save the tooth and surgery is often necessary. Common problems include ledging, debris being pushed into the root canal and broken instruments.

'There are many factors that can make an endodontic procedure more difficult, including the type of tooth, the morphology of the canal and root (curved roots, narrow canals, divided canals), and the history of the patient. It's important that dentists know when something is beyond their capabilities and make an early referral to a specialist. The American Association of Endodontists (AAE) has produced a case difficulty assessment form and guidance which can help you evaluate the patient and decide whether a referral is appropriate.

'If you do carry out the treatment, it's essential to warn the patient about possible complications so they can give informed consent and have realistic expectations. These include the possibility of damage to an existing crown, the risk of post-treatment flare-ups and of course, the risk of failure and subsequent tooth loss.

'One of the most important things to stress to patients ahead of the procedure is that they must speak up immediately if they feel a painful burning sensation as it means sodium hypochlorite has been extruded beyond the root canal. This is a rare complication but it can cause catastrophic damage if not caught early. Some research studies suggest that the most susceptible patient group is middle-aged women, particularly when receiving treatment to an upper premolar or molar.

'As with any treatment, dentists have to be trained and competent to provide endodontic treatment. Develop your technical skills and knowledge on a training course to give you the chance to practise on extracted teeth. But given the risks and complexity of root canal procedures, the most important skill that practitioners may need is saying no when the treatment is way outside their comfort zone or skill level.'