Dental professionals often carry out procedures involving very small instruments, and occasionally hazardous materials, and patients generally trust them to do so. However, foreign body ingestion is a well-known complication of dental treatment. The risk factors involved in the dental environment include the difficulty in handling small instruments and other objects such as restorative materials while working in the restricted area of the mouth, coupled with the patient being treated while lying back in the dental chair.

DDU analysis

Despite this, in the DDU's experience the number of successful claims resulting from a patient inhaling or swallowing a foreign body is relatively low. During a recent ten year period, we opened 68 case files and settled 22 formal negligence claims in this area, ranging in size from under £500 to over £25,000 in compensation and legal costs.

The five most common procedures identified in the DDU's files were:

• endodontics: 16 cases
• fillings: 15 cases
• scale and polish: 5 cases
• implants: 5 cases
• extractions: 4 cases.

Other procedures which featured in the files were orthodontics and bridgework.

The most common instruments or materials to be accidentally swallowed or inhaled were:

• endodontic files/reamers: 17 cases
• burs: 17 cases
• filling material: 8 cases
• implant screwdriver: 4 cases
• prosthesis (crown, veneer or implant): 4 cases
• scaler tip: 4 cases.

The majority of cases (80%) concerned incidents of accidental swallowing, which generally required no further treatment as the instrument passed uneventfully through the patient's gastro-intestinal tract. In a handful of these cases, the patient had to attend accident and emergency for an X-ray, and in at least two cases gastro-intestinal surgery was needed to remove the foreign body.

Of patients who inhaled a foreign body, the outcomes were generally more serious because of the risk of choking and infection. A small number of patients required hospital treatment, including emergency bronchoscopy or surgery, to remove the object.

Dento-legal implications

Although these adverse incidents are rare, the risk of anxiety and potential harm to patients can be significant. There can also be serious consequences for the dental professional involved, as well as possible reputational damage for the practice.

It can be difficult to argue that a dental professional was not negligent if the incident results in a claim, but it may be possible to successfully defend them if suitable precautions were taken to mitigate the risk of harm.

Duty of candour

This type of incident would usually meet the threshold for the statutory duty of candour. In such situations, the dental practice is required to formally notify the patient, provide a full explanation of what is known at the time (as well as an apology) and provide reasonable support. The practice would also be obliged to notify the CQC (or the relevant national regulator) about serious patient safety incidents.

After any serious adverse incident, it's important for you and your practice to reflect on what happened and the lessons learned, and to implement necessary changes. Contact the DDU or your own dental defence organisation for advice about your obligations.

DDU advice

The following advice, based on the DDU's analysis, will help you limit the risk of a patient swallowing or inhaling a foreign body during dental treatment and make sure you're in a position to manage any incident appropriately.

• Consider using securely positioned rubber dam to isolate the affected tooth or teeth when carrying out procedures like fillings or root canal treatment, as suggested by research in this area. If it's not possible to apply rubber dam because the tooth is broken, consider other measures, such as a parachute chain, throat sponges or gauze throat screen.
• Use high vacuum suction when carrying out procedures such as cementing crowns or removing fillings - again, an approach suggested by researchers.
• If you're concerned that a patient is at particular risk, consider postponing the procedure or referring them for treatment.
• Make sure dental instruments are regularly checked and serviced so they are in good condition and working properly before use.
• If you drop a dental instrument in the patient's mouth, take immediate action to retrieve it if possible, then tell the patient and apologise.
• If you suspect something has been inhaled and the patient can't cough it up, they should be advised to attend hospital for investigation. You should provide a detailed referral letter, and it can be useful to include a sample or picture of the instrument with a ruler alongside, so the size of the instrument, as well as what it's made of, is clear to the A&E doctor.
• If the patient can't be persuaded to attend hospital, they should be given advice on red flag symptoms and what action to take.
• Patients who have swallowed or inhaled an instrument should be closely monitored until it has been passed in the faeces or removed.
• Make full records - document exactly what happened, the action taken and the discussion with the patient.
• Ensure the incident is reported appropriately and seek advice from the DDU.

This article first appeared in Dentistry magazine and has been edited for publication here.