Surface Disinfection 101

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Best practices for surface disinfection in dental practices.

Somethings are just so simple, so basic that an explanation doesn’t seem necessary, but sometimes the details are essential. Case in point: surface disinfection. How hard can it be? You wipe on the chemical and then wipe it dry. The fact of the matter is that it’s not so simple. Surface disinfection is an important cog in the infection control machine and one that, regrettably, is often taken for granted.

It starts with the disinfectant chemicals, which are regulated by the Environmental Protection Agency (EPA).

“Disinfectant chemicals are unique,” Jackie Dorst, RDH, BS, observes. Dorst is an infection prevention consultant and speaker. “Disinfectants are regulated by the Environmental Protection Agency, and they come under the category of pesticides. These chemicals have a toxicity to be able to kill the microorganisms. And, of course, we want a chemical to use in healthcare that kills any pathogenic microorganisms in the categories of bacteria, fungus, or viruses. So, EPA regulates and approves disinfectants in different categories of efficacy.”

Those disinfectant categories come with varying levels of toxicity.

“Low-level disinfectants are more those janitorial-type chemicals that you would use in any public place during the pandemic,” Dorst says. “We all saw, even at the grocery store and at retail stores, that the carts that you pick up were wiped down with the disinfectant before you used it. Those were mostly low-level disinfectants, not the higher EPA List E disinfectants that are approved for healthcare and will kill those pathogenic microorganisms or disease-causing microorganisms. Healthcare disinfectants would be in an intermediate level category.

“There are also some disinfectants referred to as a high-level disinfectants, commonly called – in dental practices – ‘cold sterilization’,” she continues. “A high-level disinfectant will kill all vegetative microorganisms, but it doesn’t normally kill spores, and it’s very toxic. You can imagine, if it’s going to kill everything and it’s a liquid that we soak items in, then it’s got to be extremely toxic and very hazardous for the person using it.”

The appropriate chemicals for healthcare settings are included in a specific list.

“EPA has a list and it’s called the List E, which is for healthcare disinfectants,” Dorst says. “Any dental practice that wants to verify the disinfectant that they’re using is approved for healthcare and is it going to kill those pathogenic microorganisms, they need to search on the label or on the safety data sheet and locate the EPA registration number. They’ll use that registration number to search this EPA List E.”

Follow the Directions
It may seem that common sense dictates how to simply open a container of disinfectant wipes or spray on a disinfectant and wipe it dry. However, each disinfectant has its own usage rules, and those are laid out by the manufacturer.

“I think that people often don’t read the manufacturer’s instructions or the label on the actual product that they’re using,” Karen Gregory, RN, Director of Compliance and Education for Total Medical Compliance, observes. “And they may not make sure that the contaminated surface stays wet for the appointed contact time. Only when that contact time is met can you have the assurance that there has been adequate disinfection of that surface.”

“Contact time” is the magic phrase governing a disinfectant’s use.

“That’s the phrase that they’re looking for,” Dorst adds. “How long is it? It can be anywhere from 10 minutes to 1 minute. You don’t want just the shortest kill time that it says to kill a few microorganisms such as polio virus. There may be 5 different microorganisms that are listed on the front of the label, and it says, ‘Kills these in 30 seconds’. But then when you turn the label around and read the detailed instructions for effective disinfection in a healthcare environment, the manufacturer’s IFU may say, ‘But to kill all pathogens, leave wet for 5 minutes.’ That’s back to basics. What are the best practices for using a disinfectant?”

Regrettably, even the most seasoned professionals fall into bad habits.

“I had a clinician contact me within the past year, and she didn’t realize that the wiping portion of the spray – wipe – spray process was wiping with a paper towel,” Gregory says. “Her comment was, ‘I just didn’t read the directions’. I think, as adults, a lot of times we don’t read the directions. We also get so focused on turnover of that operatory because that next patient is waiting, that the appropriate time is not spent on the cleaning and disinfection process. This also may link back to, ‘I know how to do this. I’ve been in dentistry long enough’.”

Rudimentary as it may sound, team members must also keep an eye on the clock when disinfecting.


“When it comes to contact time, I feel like people don’t really understand how long 1 minute is or 3 minutes is,” Gregory says. “Contact time is equal to kill time. That surface has to be in contact with that disinfectant for the appropriate contact time to kill any contaminates that may be on that surface.”

Also, it’s important that staff take appropriate measures to protect themselves while using disinfectants.

“People may not realize how often they are coming in contact with these surface disinfection chemicals,” Gregory observes. “They may not protect themselves adequately. Over the course of 1 year workers could be exposed to this chemical thousands of times. I still have managers say to me, ‘I had a worker that was doing surface cleaning and disinfection, and they weren’t wearing any gloves’. So, knowing that this is a chemical and that they should be protecting themselves when they’re using the chemical, I think is something that needs to be stressed.”

How a product is applied is another important consideration with surface disinfection.

“A surface must be clean before you can disinfect it,” Dorst reminds. “Then the next step is to apply the disinfectant, and everybody’s heard this phrase, ‘Leave it wet for the contact time to kill all the microorganisms’. And that’s the important piece of information that is going to be on those detailed manufacturer’s instructions for use (IFU) on the back of that label.”

How the chemical is delivered matters, as well. That is, is the chemical used to spray onto the surface or applied using a premoistened wipe? Each has its own method of application.

“Most offices, for convenience, have gone to using disinfectant wipes,” Dorst says. “Not all wipes are the same. Some of them are a smaller size. Some are a larger size. Some of the disinfectant wipe containers contain more of the chemical. And those wipes are what I refer to as ‘juicier’. You really want a juicy wipe. When an assistant or a hygienist pulls that wipe out, it goes through a little sweeping process that wipes off the excess. You don’t want it to be dripping chemical all over every surface, but when you pull that wipe out, it should be wet enough that if you squeezed it in your hand, you could get a few drops of chemical out. If it’s not juicy and when you pull that wipe out and you squeeze it in your hand and nothing comes out, then that wipe is too dry. It doesn’t have enough chemical in it to leave the surface wet for the contact time to kill all the pathogens.”

Team members must also be mindful of how they are applying the surface disinfectant, being careful to be thorough.

“What is your technique for wiping down those surfaces?” Dorst asks. “Because a quick swipe over could miss some critical surfaces. It only takes a few viral particles of the norovirus to transmit a disease or a few viral particles of measles. Or as we have learned, if someone’s coughing with a COVID infection, and those aerosol droplets are on the surface –and we don’t get them clean – then touch that surface with our gloves on as we’re treating the patient there is a risk of infecting the patient (cross contamination).”

Check Your Work
Surface contaminants are hard – impossible, really – to see. The right product and a good technique is, of course, necessary to eliminate those contaminants.

To underscore just how hard it is to see contamination, the Organization for Safety, Asepsis and Prevention (OSAP) produced a video called “If Saliva Were Red”. The video graphically depicts how patients’ saliva is left all over the operatory – including on team members.

“I would encourage people to see that video,” Dorst says. “It allowed us, with a dye, to see where the red splashes were in an operatory and why we need to wear PPE and what surfaces needed to be cleaned and disinfected.”

“The “If Saliva Were Red” video shows all the contamination that occurs in dentistry through the delivery of care,” Gregory adds. “If you could see where it was, you would be really surprised. There may be a contaminated surface that, because you can’t see the contamination, you might not clean it as well as you should. The takeaway is that that surface cleaning and disinfection is critically important, because there may be areas that are contaminated and you can’t see the blood on it. Just think about everywhere your hands may have touched or where you may have put a contaminated instrument, and make sure that those surfaces are taken care of appropriately.”

Dorst recommends using a product called Highlight, which is an additive that colorizes bleach spray so team members can visualize where bleach has been applied.

“Something like Highlight that can be added to the disinfectants is another visual that will prove to be a training benefit for many dental practices,” she says. “As we have new team members join the office – and as a refresher for us experienced infection preventionists – we need to be thorough with our cleaning and disinfection, so we don’t have any of those missed surfaces that could inadvertently transmit a disease.”

Surface disinfection may seem like an easy, rote task. However, taking the process for granted is the first step down the path toward a terrible mistake.