Sir, I felt I must contact the BDJ after reading the paper in BDJ 2004, 197: 527. This, I believe, is the 6th in a series of endodontic papers and covered the subject of rubber dam.

I agree with Dr Carrotte that the use of rubber dam may protect patients from inhalation or ingestion of foreign materials at the time of restorative dental work being carried out. I also believe that where inhalation is suspected, in either an adult or a child, further investigation is required. The Royal College of Radiologists have produced guidelines for clinicians which, among other topics, covers the situation of foreign body inhalation/ingestion. In the adult patient without abdominal signs or symptoms the only radiograph indicated would be an Antero-Posterior Chest Film.1

Figure 1 in the paper by Dr Carrotte claims to show 'An endodontic instrument has been inhaled due to a lack of airway protection.' This is incorrect. The Figure 1 radiograph is in fact a plain abdominal film showing a small, radio-opaque abnormality (possibly a foreign body; and possibly even an endodontic instrument) lying at the level of L1-L2. I think this merits a mention as this radiograph would not be indicated in most cases and in fact represents ingestion rather than inhalation, if indeed it represents either.

Author of the paper P Carrotte responds: I am grateful to Mr Devlin for his observations, indeed I would like to thank all those who have contacted me either by letter or e-mail with interesting and often helpful comments related to this series of endodontic papers.

In reply to Mr Devlin, may I first say that I was sorry that he chose to doubt what could clearly be seen on the original and full sized radiograph. That aside, the picture was intended to illustrate one of the serious consequences of not using rubber dam during root canal treatment and not to give radiographic advice, but I am indeed grateful to Mr Devlin for drawing the Royal College of Radiologist's Guidelines to the attention of the dental profession.

It would appear that these may not have been as widely disseminated as the College would wish, as several colleagues to whom I have spoken would have ordered a plain abdominal film in the unfortunate event of loss of a sharp object by ingestion or inhalation.

Having read a copy of the guidelines I find that they are, in fact, both detailed and complicated depending upon several different case scenarios, and the prudent clinician would obviously be advised to seek professional radiographic guidance in this unfortunate situation. This will certainly be discussed in the next edition of the BDA's textbook A Clinical Guide to Endodontics from which the papers were taken.