Prions in dentistry--what are they, should we be concerned, and what can we do?
OBJECTIVE
To briefly review the characteristics of prions, the risk of transmission and implications for infection control in dentistry.


METHODS
The literature on prion disease in the context of dentistry up to March 2005 was reviewed using the PubMed, MEDLINE, Cumulative Index to Nursing & Allied Health Literature, Google Scholar databases and the Web sites of the departments of health of countries affected by the disease.


RESULTS
The sporadic form of Creutzfeldt-Jakob disease (CJD) is the most common human prion disease; the mean age of those affected to date is 68 years, the mortality rate is 85% within 1 year, and the average death rate is 1 per million persons. Variant CJD (vCJD) affects people (mean age 26 years) with a history of previous extended periods of residence in certain countries, mainly in the United Kingdom. Currently, there is no evidence of human-to-human transmission of CJD or vCJD following casual or intimate contact or blood transfusion, nor is there evidence of iatrogenic transmission of vCJD in a health care setting. Furthermore, there is no evidence indicating increased occupational risk of CJD or vCJD among health workers or clustering of vCJD among people associated with a dental practice. The risk of transmission of prions through dentistry is unknown but is thought to be very low if appropriate infection control measures are taken.


CONCLUSIONS
The theoretical risk of transmission of prion disease through dental treatment emphasizes the need to maintain optimal standards of infection control and decontamination procedures for all infectious agents, including prions.
Azarpazhooh
Amir
A
Department of Community Dentistry, Faculty of Dentistry, University of Toronto, Toronto, Ontario. amir.azarpazhooh@utoronto.ca
Leake
James L
JL
D000818:Animals; D001803:Blood Transfusion; D002170:Canada; D017742:Dental Care for Chronically Ill; D003762:Dental Instruments; D018562:Disease Transmission, Infectious / Q000517:prevention & control; D004866:Equipment Contamination / Q000517:prevention & control; D017408:Guidelines as Topic; D006801:Humans; D019552:Infection Control, Dental / Q000379:methods*; D017096:Prion Diseases / Q000635:transmission*; D012307:Risk Factors; D014944:World Health Organization