Untested autoclave, tools for ‘infected’ patients

‘No sterilization log was present’

The state investigative report in a Tulsa dental practice where the first case of hepatitis C virus transmission between patients occurred found some extraordinary lapses in the sterilization protocols for used instruments.

In a particularly strange protocol, two separate sets of dental instruments were kept, one set for patients “known” to have infectious diseases and another set for patients “unknown or not believed to have an infectious disease,” investigators were told.1

It goes without saying that the subjective nature of this process and the known window period for various bloodborne infections — even if frequent patient testing was done — would not allow a caregiver to accurately triage infected and non-infected patients in such a fashion. The two instrument kits had separate cleaning protocols, with the set for “infected” patients dipped in bleach as an extra step. As a possible result of this policy, the instruments designated for infected patients appeared to be rusted and could no longer be properly sterilized.

“The areas where rust occurs on an instrument do not allow the sterilization process to work properly,” says Noel Brandon Kelsch, RDHAP, of Moor Park CA, a registered dental hygienist in alternative practice and past president of the California Dental Hygienists’ Association. “We use stainless steel products to avoid rusting. If rusting does occur, we remove the item from service before it leaves sterilization so there is no risk to the patient.”

The report also raised questions about the instruments that were wrapped and stored and noted that standard sterilization bags were not used.

“We follow all the protocols for sterilization and monitor them step-by-step,” Noel says. “In our practice, we use three methods to assure that sterilization has occurred. We have a system in the sterilizer, a system on all our bags, and we send out a weekly spore test to make sure the system is working. We open the packages in front of [patients] so you can be assured they are safe, and we can show you the indicator we use.”

Compounding the problems in the Tulsa office, the autoclave used to sterilize instruments had apparently not been bio-tested for efficacy in years.

“The autoclave used to sterilize all the instruments was not being properly used,” the report states. “According to the manufacturer’s instructions, a monthly test is required to be performed and sent to a lab to determine that the autoclave is successfully sterilizing all instruments. No such test had ever been performed in the six years one dental assistant had been working at the office. No sterilization log was present or had been kept by staff.”

No benefit of the doubt

HIC asked Roland Arnold, PhD, a professor of diagnostic sciences and dental research at the University of North Carolina School of Dentistry in Chapel Hill, to comment on the autoclave findings.

“Most autoclaves if operated properly are able to kill the bacteria in the spore strip which in concept are harder to kill than most pathogens,” he says. “Sterilizers do however fail either due to mechanical failure or operator error. There are several levels of failsafe for sterilizers, none of which this office seemed to be practicing. Without any monitoring, we just don’t know how the autoclave was functioning. Given all the other violations identified, I wouldn’t give [them] the benefit of the doubt.”

The state of North Carolina has very clear rules regarding sterilizer monitoring, which include keeping log books of temperature and/or pressure, time and chemical indicators for every time the sterilizer is run, he added.

“In addition the state requires that biological testing be done at least once a week to confirm the ability of the sterilizer to kill heat-resistant bacterial spores,” Arnold says. “This is usually done by a third party, which is our role. We test approximately 2000 sterilizers per week.”

If a sterilizer fails in testing it is taken offline and any instruments that were run in the interim are not used until the cause of the failure is identified and fixed, he says.

“As far as I am aware, offices are regularly monitored for compliance to these rules,” he says. “We average approximately 15 failures per week. We work with the office to identify the problem. There are certainly instrument failures that occur on a regular basis, but by and large most failures are due to user error that are easily rectified. “

If needed, sterilizer manufactures are generally very good about providing loaner sterilizers while mechanical failures are addressed, he adds.

“We also monitor dental unit water lines,” Arnold says. “This is not a state regulation, but the CDC and the ADA recommend regular testing. We know that if there is no regular disinfection protocols in place that all dental unit water lines will become contaminated with bacterial loads that exceed acceptable levels for drinking water and certainly exceed the CDC and ADA recommendations. This can be the source of potentially infectious agents, especially in compromised patient populations.”

Indeed, it was recently reported that patients of a now-closed dental clinic in Marana, AZ, are being advised to be tested for hepatitis or HIV. The Pima County Health Department is contacting 174 dental patients who were seen at the clinic from January to July of 2010. Reportedly, an improperly installed air compressor that supplied both air and water to patients created the possibility of cross transmission via medical waste. There have also been reported cases of pneumonia and Legionnaires Disease associated with contaminated dental water lines.2


1. Oklahoma Board of Dentistry. Statement of complaint against Wayne Scott Harrington, DMD. March 28, 2013. Available at: http://www.ok.gov/dentistry/

2. Ricci ML, Fontana S, Pinci F, et al. Pneumonia associated with a dental unit waterline. The Lancet 2012;379:684