Ask Nancy Andrews from TotalCare

Feb. 18, 2013

Readers submit their questions to expert Nancy Andrews:

Q: We are wondering which way to place sterilization bags into the autoclave ... plastic side up or plastic side down? -- Terri

A: Terri, this is an issue that confuses many people. First, if you have racks and can stack the pouches on their sides (plastic touching paper, all facing the same direction), this is the best.

For those who lay the pouches down, the answer depends on the direction of the steam flow in your sterilization chamber. If you have a gravity steam sterilizer, the steam will rise inside the pouches. If the plastic side is up, it traps the steam; condensation collects inside the pouch under the plastic and drips down on the instruments. So, for gravity steam sterilizers, place the paper up so the steam will escape and dry better.

If you have a vacuum sterilizer, the vacuum directs the steam downward to vent. For those models, place the paper down and the plastic up.

Q: We are concerned about the environmental impact of plastic barriers. However, we are more concerned with patient safety. Our local dental hygiene program has recently discontinued the use of all plastic barriers. We cannot find any definitive information on whether or not to use barriers, or should we just use approved wipes? Please help! — Jacqueline

A: Jacqueline, your question about the environmental impact of surface barriers is a growing concern among many members of the dental community. The worldwide issue of environmental protection should, in my opinion, be at the top of everyone’s list of challenges. At the same time, patient protection is a requirement of our role as clinicians, and many of us are confronting ways to better balance these two goals. Unfortunately, information that helps us compare the overall environmental impact of using barriers vs. chemical disinfectants is not readily available.

As you said, the other issue is reliable infection control. Research comparing surface disinfection vs. using new barriers for each patient shows that if both methods are used correctly, they provide similar reliability. Therefore, each office must optimize factors such as time efficiency, patient preferences, cost of supplies, storage, and waste management. Most offices use barriers on a few complex surfaces that take more time to clean and disinfect. Barriers improve time efficiency and are believed to reduce human error that result from time and technique limitations. The barriers are visible and communicate asepsis to patients, which some may view positively, or in some cultures may see as a wasteful use of plastic.

The bottom line is that there is no compelling science to support either barriers or disinfectants as superior — both are equally effective and neither is clearly more environmentally “green” than the other. If recyclable barriers can be used and recycled from dental offices, barriers might offer a more sustainable option than chemicals.

Q: We use the same prophy angle handpiece (the motor) for an entire day of patients, wiping it down between patients with CaviWipes. Is this OK?

A: In the past, leaving slow-speed handpiece motors on the cord connectors and wiping them with surface disinfectants between patients was accepted. Only the prophy angle was removed and autoclaved or disposed of. The rationale for this was that the slow-speed motors worked differently than the high-speed handpieces. Because they do not have air and water passing through them, they were thought to be “clean inside.” Also, the motor portion was considered less critical because it typically remains outside the mouth. The recommendations changed after research showed that slow-speed motors can become contaminated internally and are potential vehicles for disease transmission. Current recommendations are to remove the slow-speed motor and sterilize it between patients. You should always consult your manufacturer’s instructions for cleaning and sterilization.

Many people think that sterilizing slow-speed motor handpieces will be much more costly. However, equipment repair experts say that wiping the outside of a slow-speed motor with any surface disinfectant is likely to introduce disinfectant into the motor and shorten the life of the mechanism more than if it is correctly processed through sterilization cycles. So, while sterilizing requires having more handpiece motors, they should last longer.

Q: Will a surface disinfectant that kills M. tuberculosis also kill MRSA? Or does that function need to be stated separately in the directions? — Sharon

A: Sharon, whenever a company claims efficacy against a particular organism on the label, it has been tested specifically against that organism and is therefore more reliable than if the target organism is not listed on the label. Having said that, the concept that intermediate-level disinfectants have been tested against mycobacterium tuberculosis, a benchmark organism, implies strongly that the product should destroy other, less resistant pathogens. However, it is not guaranteed unless it is stated on the label. The key factor that must not be forgotten here is contact time (the time a surface remains wet during disinfection, after precleaning). Some pathogens actually require more contact time than TB, depending on the disinfectant. Vegetative bacteria, including MRSA, are generally considered to be within the group of organisms that intermediate-level disinfectants kill during the recommended contact time, but due to the resistant nature of MRSA and the importance of controlling this pathogen, I recommend using a product with this target organism specifically listed on the label.

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