By Dr. David Lewis | TLB Science Advisor
In 1992, the CDC and FDA began recommending heat-sterilization of dental handpieces used to drill and polish teeth. According to my industry sources, however, compliance may currently be as low as 50%, particularly in low-income areas of the Deep South. Many dentists are just wrapping their handpieces in disinfectant between patients. When heat-sterilization guidelines aren’t followed, you and your family are at risk of contracting hepatitis C, HIV and other infectious agents.
Public health organizations worldwide adopted the current heat-sterilization standard after research my coauthors and I published may have explained how an outbreak of HIV in a Florida dental practice occurred in the late 1980s. There, at least six patients were infected with their dentist’s HIV strain, which he acquired from one of his sexual partners. Investigators discovered that he used poor infection-control, and treated his HIV-infected partners after hours.
In studies we published in Lancet and Nature Medicine, I organized a team of researchers at Washington University’s Retrovirus Clinic and Loma Linda University’s School of Dentistry. Dr. Benjamin Patrick, my family’s local dentist in Athens, Georgia, coauthored the study. We demonstrated that even the fragile AIDS virus can survive disinfection when trapped in lubricants and patient materials that collect inside dental handpieces. When these devices are reused, infectious material can be ejected directly into open wounds in the next patient’s mouth. The risk is similar to a nurse experiencing a needle-stick injury while injecting an HIV-positive patient.
Regular dental care not only saves your teeth. It may save your life as well. Still, I would never let any dentist or hygienist work on my family’s teeth if their handpieces are not heat-sterilized after every patient. Only heat can penetrate patient materials that collect inside them. And, the risk of not heat-sterilizing them may be far higher than many dentists realize.
As pressurized air drives turbines inside high-speed handpieces during drilling, patient materials are constantly being sucked back into the devices. Red blood spit back out when handpieces are reused and not heat-sterilized can be visualized by simply operating the drill in contact with water, or placing the contaminated turbines in water.
Dentists who don’t heat-sterilize their handpieces often point to a lack of documented cases of infection. Usually, however, infections are only documented when outbreaks involve scores or hundreds of patients at the same facility. Sporadic infections spread over many different dental practices go unnoticed. Normally, your family doctor would never consider the possibility that your hepatitis C infection, for example, may have been caused by a blood-contaminated dental handpiece. Still, considering how often dental handpieces are being reused without heat sterilization, the total numbers of infections occurring nationally could be very large. Every patient should ask his or her dentist: “Do you heat-sterilize your handpieces after every patient?”
David Lewis, Ph.D.
Former U.S. EPA Research Microbiologist
David Lewis is an internationally recognized research microbiologist whose work on public health and environmental issues, as a senior-level Research Microbiologist in EPA’s Office of Research & Development and member of the Graduate Faculty of the University of Georgia, has been reported in numerous news articles and documentaries from TIME magazine and Reader’s Digest to National Geographic.
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