This page contains general Dental Decontamination questions.
What are the main public health risks associated with reusable instruments?
Any medical or dental procedure that has the potential to transfer infectious tissue between patients must be regarded as a potential health risk. The principal concern for dental instruments is that improper sterilization might lead to the transfer of tissues with the potential to cause infections such as human immunodeficiency virus (HIV), Hepatitis B and C, and variant Creutzfeldt Jakob Disease (vCJD).
Why does variant CJD appear to be the focus of attention for dental instruments?
Although there have been no reported cases of vCJD having been transmitted as a result of surgical procedures, the possibility cannot be ruled out. vCJD is a “prion” disease and therefore presents the most rigorous challenge to instrument decontamination processes. Therefore, a focus on ensuring that decontamination is effective in removing potential vCJD infectivity provides confidence that the risks from other infectious agents have been properly addressed.
What is a prion?
Prions are unconventional infection agents which may consist solely of a protein. They pose particular problems for public health because of characteristics including relative resistance to sterilisation, prolonged incubation periods and no available in vivo test for infection. There is no effective treatment.
What is CJD ?
CJD is a universally fatal brain disease, which occurs worldwide with an incidence of 1-2 cases per million per annum.
What are the potential routes of transmission of vCJD during dental treatment?
There are significant levels of infectivity in lympho-reticular and neural tissues in variant CJD. Dental instruments could be contaminated by contact with these tissues and, if inadequately decontaminated, could pose a risk of transmission from patient to patient. Direct inoculation, ingestion or contact with infective material could all potentially transmit disease.
What is the evidence for the routes of transmission for vCJD during dental treatment?
No evidence for transmission of vCJD in humans. Experiments cannot be conducted in humans. Using equivalent strains in animal models, results support the possibility of transmission via both direct inoculation and contact with many oral tissues.
Are there different oral tissues that present a higher risk of disease transmission?
Gingival margin and dental pulp contain highest levels but all oral tissues showed some infectivity in animal models.
Are there different dental instruments that present a higher risk of disease transmission?
Many instrument types have the potential to contact the gingival margin, which is both a potential source of infectivity and a potential route of transmission. As such, emphasis should be on effective decontamination for all instruments.
There is no evidence of transmission of vCJD, so why do we have to make all these changes?
There is currently no evidence that vCJD has been transmitted by clinical dental practice, although collecting appropriate epidemiological data is difficult. A number of experimental studies have highlighted the potential infectivity of oral tissues reinforcing the need for continuing best practice in instrument decontamination. It is possible that dental/oral tissues of patients already infected could carry the infective agent. If so, material adhering to instruments may transmit infection to subsequent patients treated with the same dental instruments. The very large number of dental procedures performed annually means that even small transmission risks per procedure could create an appreciable risk to public health. The risk of transmission of vCJD and other healthcare acquired infections will be greatly reduced by compliance with current decontamination policies and procedures for all patients as outlined by the HPS LDU guidance.
How could routine dental procedures such as fillings present a risk of vCJD transmission?
A number of laboratory studies in animals have shown that dental/oral tissues such as, tongue, gingiva, dental pulp and saliva have been shown to contain infectious material for prion diseases. Consequently, residual tissue on instruments following dental treatment, such as a filling, that have been inadequately cleaned and sterilized theoretically pose a risk of transmission of infectious agents to subsequent patients.