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Your tooth just broke my file!

25 March 2022

Dr Roger Dennett, Dentolegal Consultant at Dental Protection, considers the commonly reported incident of a fractured endodontic file in the context of a recent case

Hopefully, “your tooth just broke my file” are not the not words practitioners use when an endodontic file breaks inside a canal. We are all too aware that the performance of such treatment is a delicate operation, involving fine and often calcified anatomy and using delicate and sometimes fragile instruments.

File fracture is a common enough event, and yet it can be said that the event is often unforeseen and not understood by the patient. Patients do not necessarily appreciate the surgery at the same level as the dentist, and they often have a vastly different perspective.

Who is in control?

People feel safer when they perceive that they are in control. Lay people are often inherently talented at weighing benefits and risks. Most patients recognise that different treatment options represent a trade-off in terms of aesthetics, time, comfort and cost.

It is critical that every patient is meaningfully aware of the risks and warnings of their treatment, and patients would likely prefer to hear that there is zero risk of an adverse outcome, but as we all know that is not true. How do we impart this valuable information to patients, so that they can make an informed decision and consent to treatment?

An article that reviews negligence claims and complaints in Australia concerning consent makes for interesting reading:

“Malpractice complaints and claims regarding informed consent are not uncommon events. When they arise, they are most likely to centre on a mundane factual disagreement over who said what and when. This underscores that, for the informed consent process - like most other areas of clinical dental practice - regular and careful documentation of interactions with patients is a prudent risk-management strategy. Documentation of the details of consent discussions in the lead-up to clinical or surgical procedures is particularly important, as most informed consent disputes involve complications following operations.

“Courts do not accept that merely handing a consent form to a patient, however well designed and exhaustive the form may be, is a valid way of obtaining informed consent. Consequently, clinicians must decide which risks to discuss and emphasise. For busy dentists, this necessitates choices, because time is limited, and effort devoted to consent discussions has an opportunity cost. Courts regard the possibility of an adverse outcome occurring as a crucial element in determining what qualifies as a “material risk” that must be disclosed, but it is only one of several elements.”

Rarity and severity

“The severity of an outcome associated with a risk also matters. Rarity and severity are considerations which operate together. A small risk of a catastrophic outcome usually warrants emphasis, as does a substantial risk of a relatively minor adverse outcome, but not a low risk of a minor adverse outcome. A common example in the case of oral surgery to remove a lower molar would be the risk of jaw fracture, which would require specialist surgical treatment to immobilise the jaw and would involve the patient in significant levels of pain, swelling and incapacity to work as well as a period of hospitalisation and interference in their daily life. Such would be regarded as an example of a small risk with a catastrophic outcome.

“It also must be recognised that details of risk tend to matter more towards the elective end of the treatment spectrum than the urgent end, which goes some way to explaining the higher incidence of post treatment dissatisfaction associated with cosmetic dental procedures.” [1]

Communication post-treatment: honesty is the best policy

The need for effective communication to ensure valid consent principles have been met prior to treatment is universally recognised. What about the situation that arises when a mistake has been made, or when there is a treatment event that exposes the dentist to a complaint?

Honesty is the best policy. If something untoward occurs during treatment, inform the patient and let them know you will work with them to rectify the problem. An honest and apologetic approach, coupled with a genuine wish to assist the patient, can defuse any negative emotions that the patient may initially express and avoid a claim being pursued.

If remedial treatment is required, discuss the options of carrying it out yourself if you are suitably competent to do so, or refer the patient elsewhere. Leave it to the patient to decide which path to choose. It is desirable and helpful that, wherever possible, cost is not a consideration at this point. Offers of financial assistance, when appropriate, often help minimise any friction with the patient and bring about resolution of the matter.

Case study: A perforation during root canal therapy

A patient presented for emergency treatment of pain on the lower right side of her mouth. The dentist commenced RCT on the deeply filled 46, during which he perforated the lateral wall of the mesial root. This was confirmed radiographically.

It was explained to the patient that the perforation had occurred and this had reduced the prognosis for long-term retention of the tooth. A specialist endodontic consultation was recommended should the patient wish to continue with the treatment. The patient, fortunately, was not too concerned and was more interested in having the tooth extracted and a bridge placed. She declined specialist referral.

After further discussion, the dentist suggested that she consider what had been discussed before making a final decision and temporised the tooth. The following day the patient experienced severe pain and attended another dentist at the practice who adjusted the temporary filling, provided a script for antibiotics and analgesics, and referred the patient to the endodontist. One month later, the patient wrote to the practice principal accusing the assistant dentist of being “negligent” in his treatment of her. She stated that she had not been given any antibiotics or painkillers by him, the temporary filling had not been completed properly, and he should not have commenced RCT if he was not capable. She advised that she would now be continuing treatment with the endodontist.

The original treating dentist sent a courteous letter of reply to the patient outlining how the perforation had come about and been addressed, their detailed discussion about the problems with it, and treatment options available for tooth 46 at a visit prior to the RCT appointment. As a result of those discussions, it had been agreed that although the tooth may have to be eventually extracted, they would attempt to salvage it with RCT. The patient had been informed that no guarantees could be given and that there was a failure rate of around 10-15%. The dentist ended by saying that he was nevertheless happy to offer the patient a full refund ($200) for the treatment he had provided to tooth 46 because of the unfortunate outcome and his strong wish that he did not want his patients to feel disadvantaged by any treatment he had provided, financially or otherwise.

Five months later the dentist had still heard nothing in reply and the patient chose not to accept the offer of refund, but rather to let the matter go. The letter of explanation helped her contextualise what had happened, and once out of pain she felt very differently about the matter. The RCT was completed by the endodontist and the patient was happy with the service that had been provided. A crown was planned to be placed soon by another dentist at the practice.


Complications of a procedure are more easily dealt with when the patient has been warned about them prior to the procedure being commenced.

Perforations are more common when treatment has been conducted in an emergency appointment when staff can be rushed and unprepared. When a perforation occurs, it can be tempting to try to hide it by not taking adequate radiographs, which would assist in demonstrating the problem. However, by doing so, this may only delay its discovery (often by a future practitioner) when the inconvenient truth inevitably comes out. It was fortunate in this case that the perforation did not render the tooth unsalvageable. The outcome was assisted in part by both the dentist’s prompt admission of the problem and specialist attention at an early stage.

It was significant for the non-escalation of this case that the patient was well-informed prior to treatment. When unforeseen consequences occurred, the patient was provided with expert advice and assistance, plus a well-worded letter of explanation with a genuine expression of regret. These are key factors.

As always, if you are unsure of what to say to the patient or are having difficulty in coming to a prompt resolution with them, please contact Dental Protection. We are always here to help.

Considerations in treatment

Build the patient relationship by encouraging patients to talk.

Consent forms alone are not a valid way to obtain consent.

Consent is a process. A form may be a useful part of that process.

A dentist must determine which risks to discuss and emphasise.

Consider risk and severity – warnings about small risks with catastrophic outcomes and high risks with minor adverse outcomes.

Record details of your discussions in the clinical notes or send a follow up letter.



[1] Bismark MM, Gogos AJ, Clark RB, Gruen RL, Gawande AA et al (2012 Legal Disputes over Duties to Disclose Treatment Risks to Patients: A Review of Negligence Claims and Complaints in Australia. PLoS Med 9(8): e1001283

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