Cross Infection

The emergence of vCJD has provided significant challenges to infection control and instrument decontamination procedures in all areas of health care. In particular it has highlighted the absolute importance of instrument cleaning, to permit removal of protein and other biological materials from instrument surfaces prior to sterilisation. Difficulties have arisen in relation to those instruments and items of equipment which cannot be readily cleaned. Within dentistry, endodontic files have come under close scrutiny because of their small size and complex surface topography, within which debris can accumulate.

Two recently published papers (1,2) have identified that following standard instrument cleaning procedures, a very high proportion of used endodontic files have residual debris on them, visible by low power microscopy. Furthermore, residual protein was present on all of 220 cleaned files examined. This objective evidence strongly supports the contention that endodontic files should be viewed as single use devices, unless significantly more effective cleaning methods can be devised that are suitable and validated for use in dental practice.

In May 2006 the UK Spongiform Encephalopathy Advisory Committee (SEAC) released a position statement on vCJD and endodontics which concluded that: 'It is unclear whether or not vCJD infectivity can be transmitted via endodontic files and reamers. However, given the plausibility of such a scenario and the large number of procedures undertaken annually, it would be prudent to consider restricting these instruments to single use as a precautionary measure. Since sufficiently rigorous decontamination of these instruments is difficult, single use of these instruments would eliminate this risk, should it exist' (http://www.seac.gov.uk/statements/statement0506.htm). On the basis of the evidence now available, there can be no doubt that this is best practice.

1. LETTERS S, SMITH AJ, MCHUGH S, BAGG J (2005)
A study of visual and blood contamination on reprocessed endodontic files from general dental practice.
British Dental Journal 199: 522-525

2. SMITH A, LETTERS S,
LANGE A, PERRETT D, MCHUGH S, BAGG J (2005)
Residual protein levels on reprocessed dental instruments.
Journal of Hospital Infection
61: 237-241

Professor Jeremy Bagg PhD, FDS, FRCPath, FFPH
Professor of Clinical Microbiology & Head of School
University of Glasgow Dental School, 378 Sauchiehall Street, Glasgow G2 3JZ

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