Sir, the letter Rubber dam purpose by R. Mackay (BDJ 2008; 205: 295–296) gave a good argument for not using a rubber dam. In fact we agree on many of the points made. However, a timely reminder of the perils of working without a dam presented itself to our department a day prior to the publication of this letter.

Although we acknowledge that R. Mackay does stress that 'by taking a number of simple measures' endodontic work poses little risk to the patient, rubber dam is a quick to apply, simple to use, inexpensive yet effective tool. It ensures the safety of the patient and high quality work from the clinician. Its use has few contra-indications.

Loss of an instrument in the oropharynx can lead to many serious sequelae. High up the instrument may become lodged in the larynx leading to a varying degree of inflammation and airway compromise. Recovery of an instrument at this level will be defined as invasive. Further down the respiratory tract the foreign body may cause inflammation, infection and bleeding within the lobes of the lung. Retrieval is technically difficult via a bronchoscope. Procedures may need to be converted to an open procedure and the possible loss of a lobe. Swallowing a sharp, needle-like tool can lead to it perforating at any level in its passage through the gastrointestinal tract. Perforations of the gastrointestinal tract needs to be managed very aggressively as leakage of its contents can result in mediastinitis or peritonitis depending on the level at which the breach occurred.

It is clear that such severe consequences can arise out of something very preventable. We would like to share an interesting case of a patient who presented to us after 'an instrument' was lost following a visit to the dentist. Initially a soft tissue radiograph of the neck was performed followed by a flexible nasendoscopy. No instrument was located. A chest radiograph was then performed which was normal. Lastly an abdominal film showed the file (Fig. 1). An urgent referral was made to the gastroenterology team who kindly arranged removal endoscopically. The patient was observed for 24 hours and discharged without incident.

Figure 1
figure 1

Abdominal film showing the lost file

Full size image

Dental defence organisations make guidelines whilst performing root canal treatment abundantly clear. Unless rotary instruments are used (held securely within a handpiece), the use of handheld files should be supported by at least a parachute chain. Their view is so strong that any injury inflicted whilst not using a rubber dam during root treatment is deemed 'indefensible'. The choice ultimately though is that of the practitioner!