By Kay Carl, RN, BS, Infection Preventionist
After reading this article, the reader should be able to:
- Compare and contrast disinfectants that are available in the dental setting.
- Select a safe and effective product for surface disinfection throughout your clinical areas.
- Devise a more efficient system for operatory turnover.
DEFINITIONSDisinfection: a process that eliminates many or all pathogenic microorganisms except bacterial spores, on inanimate objects.
Disinfectant: a chemical agent used on inanimate objects to destroy recognized pathogenic microorganisms, but not necessarily all microbial forms.
Hospital disinfectant: a germicide that is registered by the Environmental Protection Agency (EPA) for use on inanimate objects in hospitals, clinics, dental offices, or any other medical-related facility.
CATEGORIES OF PATIENT CARE ITEMSLet’s review Spaulding’s Classifications. In the mid-twentieth century, Dr. Earle H. Spaulding divided patient care items into three categories based on the risk of infection involved in their use. The three categories were critical, semi-critical and non-critical. This system has had universal acceptance in the infection control community, has been refined over the years and still is in use today.
Critical items present a high risk of infection to a patient if the items are contaminated with any microorganism. If the objects enter normally sterile tissue or the vascular system, they should be rendered sterile prior to use to prevent disease transmission. These objects should be purchased as sterile, or steam sterilized if possible.
Semicritical items address objects that come in contact with mucous membranes; high-level disinfectants may be used to process these items eliminating all microorganisms with the exception of a few bacterial spores.
Noncritical items are items that come in contact with intact skin; cleaning and intermediate or low-level disinfection is necessary if bioburden is present. Risk is only present if the contaminated objects come in contact with mucous membranes or non-intact skin.
Since the original Spaulding Classifications, the CDC added another category, Environmental, such as walls and floors that would only require cleaning or a low-level disinfectant. In general, the Food and Drug Administration (FDA) regulates disinfectants for use for critical and semicritical items and the EPA regulates non-critical and environmental disinfectants. We have to decide what disinfection process we should use for each category. It can be confusing and frustrating to find the right balance.
HISTORY OF DISINFECTANTS USED IN DENTISTRYIn the 1980s, Human Immunodeficiency Virus (HIV) was discovered. It was found to be a deadly bloodborne disease that, at the time, had no treatment and could expose both other patients and staff. We started looking for an appropriate disinfectant other than alcohol that was primarily in use in dental practices at the time. In addition, there was a concern about another bloodborne disease, Hepatitis B, that also could be a danger to both staff and patients.
As usual, dentistry was behind the curve suffering the “trickle-down effect” on what was available to us. A big reason was that if a product was accepted by a hospital, it was a major purchase, whereas a dental representative had to sell his products one office at a time. There was little incentive to do so and to be honest, little available to the market. We were eager to embrace whatever our dental supply rep could provide for us but there wasn’t much we had to work with and not a lot of information on what worked. The hospitals were struggling too, and there was little research at the time to guide us. That is why the Centers for Disease Control (CDC) first stepped in and wrote the 1985 Guideline for Handwashing and Environmental Control and then updated it to the evidence–based recommendations, Disinfection and Sterilization in Healthcare Facilities in 2008 which has been updated many times since.
When The Occupational Safety and Health Administration (OSHA) Bloodborne Pathogens Standard became law in 1992, it mandated that we use a certain type of disinfectant to kill the Hepatitis B virus (HBV) and HIV. Initially, we were required to use a hospital level disinfectant that was tuberculocidal. This meant that the disinfectant would kill Mycobacterium tuberculosis, a rather hearty bacteria, and therefore kill the weaker viruses such as HBV and HIV. Problem: the tuberculocidal disinfectants were very strong and very toxic to use. In addition, staff were not using these products appropriately. Walls were being wiped down and paint was being removed as a result. It took years but finally, the healthcare industry, along with the scientists, convinced OSHA that there were products out there that were safer to use and although were not tuberculocidal, were effective in killing the disease-bearing bloodborne viruses. In addition, we were told that we had to clean everything before we disinfected and some of the disinfectants were not compatible with cleaners. We had to clean with a different product before we could use the disinfectant which was more work and more confusion.
CHEMICAL DISINFECTANTS USED IN DENTISTRYAlcohol: 2x2’s or 4x4’s soaked in alcohol was the main disinfectant used to wipe down operatorys before the 80s. Problem: it set protein and did not clean well. It is no longer recommended for use as it is effective to inactivate certain spores and viruses.
Chlorine and Chlorine Compounds:
They have great kill times. Problems: we had to clean first with soap and water and chlorine damaged surfaces very quickly if the wrong concentration was used. Whole operatories were destroyed before personnel stopped using bleach as a surface disinfectant. It is used in hospitals to fight Clostridioides difficile, which is spread by fecal contamination.
Formaldehyde: Used to process instruments in a Chemclave Sterilizer but it was toxic, and OSHA has exposure limits, fatal if swallowed. If you still have an old Chemclave, you might want to donate it to the Smithsonian as it is dangerous to personnel.
Iodophor: Good cleaner and disinfectant. Problem: we had to mix solutions up every day, label our containers for OSHA Hazard Communication laws and was very labor intensive. It is no longer recommended because of its unproven efficacy against bacterial spores, M. tuberculosis, and/or some fungi.
Phenolic: When combined with alcohol as a popular brand did, it set protein. It was found to be very toxic and hazardous to the environment. It has been deleted as a high-level disinfectant because of its unproven efficacy against bacterial spores, M. tuberculosis, and/or some fungi.
Glutaraldehyde: Used for high-level disinfectant and chemical sterilant. Regulated by the FDA. Problem: The time for immersion is not easily monitored in a busy practice. The microbial load and wet items can diminish its efficacy and render the glutaraldehyde ineffective before its expiration date. Monitoring with test strips along with documentation is required to use it correctly. It should be in a well-ventilated area as the fumes are toxic. Best practices today avoid this product by using only single-use items that cannot be steam sterilized.
Quaternary Ammonium Compound (Quat): The original Quats were developed in the 1930’s. These solutions were made up to “sterilize” instruments in containers. Problem: Did not sterilize or even disinfect. Newer generations of Quats for surface disinfection were developed to be more effective and still are in use today. Some of these Quats more recently developed were found to be hard on some dental devices. The shields for Nomads were cracking and breaking when cleaned with Quat products that had a faster kill time. These products have warnings of flammability and toxicity to eyes and skin. Read their warnings on their labels. One manufacturer was proud to announce that their product no longer caused permanent blindness, only temporary. Read their Safety Data Sheets (SDSs).
WHAT CHOICES DO WE HAVE IN DENTISTRY?Many hospitals have eliminated the use of glutaraldehyde, formaldehyde, phenol and other disinfectants due to misuse, toxicity, and unproven efficacy, I recommend that you also consider these safety measures. Embrace the concept of steam sterilization for critical items such as dental instruments. Heat sensitive objects can be treated by chemical sterilants, but this presents numerous challenges for the process to be done correctly regarding cleaning, contact time, proper dilution, temperature, pH, and record keeping. There is also a risk management issue in the reuse of disposables intended for single use only. If the item is labeled as disposable and single use only, it should not be used on another patient. It also eliminates the possibility of processing items incorrectly and exposing employees to toxic chemicals. It also eliminates patient exposure to these disinfectants if not rinsed properly.
If we eliminate the need for disinfection for critical and semicritical items, we are down to wiping down the operatory areas that have been contaminated by touch or spray and what is connected to the dental unit that cannot be detached such as the tubing and air/water devices. We want a product that is safe and effective. We want something that will be harmless for the user, the patient and the surface being disinfected. We want a fast kill contact time. We want to only apply once, not the spray/wipe/spray we were taught or the wipe/wipe. Look at the SDSs of the products you are using. Are there still hazard warnings for their use and personal protective equipment still required? What are we supposed to use now? Are we at the point where there is such a thing as an ideal disinfectant that was not available in the past? How do we know what is safe to use and effective? There have been many studies in the past, but a 2022 Health Science Report from the National Institute of Health’s National Library of Medicine provides a meta-analysis of the relationship between cleaning product exposure and respiratory and skin symptoms among healthcare workers in a hospital setting that indicate this is a serious issue for all healthcare workers using disinfectants.
SELECTING THE IDEAL DISINFECTANTFirst. obtain information on the product that is supplied by the manufacturer, primarily the Safety Data Sheet (SDS) that is easily available on the net. What are the warnings for use? Is it toxic? Do the warnings include respiratory and skin issues? Is it flammable? Is personal protection required to use it? Remember that whatever disinfectant that you choose the SDS must be listed in your Hazard Communication Plan.
Kill Claims: Does the product kill the most prevalent healthcare pathogens?
Kill claims and Wet-Contact Times: How quickly does it kill the pathogens? For example, if you have a disinfectant that kills in five minutes, does it dry before the five minutes and therefore require another application? Some disinfectants have long contact times.
Ease of Use: Is the odor acceptable to staff and patients? Does it clean and disinfect in one step?
Other Factors: Is the cost acceptable? Does it standardize your disinfectant use? Can you use it for different surfaces in different clinical areas without changing to another product? Does it save staff time for operatory turnover?
Please note that the definition for the hospital disinfectant is for use in hospitals, Clinics, dental offices, and any other medical-related facility. If you are one of those people who buys virtually everything for your practice that you can from these clubs, be careful what you are buying. Two mistakes are easily made about the disinfectants sold there. First, if you read the directions, they indicate that these products are for household use such as kitchens and bathrooms. These cannot be used in your clinical areas; they are not hospital disinfectants. The second mistake is that many people think Clorox is another name for bleach. If it is a Clorox product, it does not necessarily mean that it contains bleach. If it is a wipe, the product is probably a Quat. Read the label.
What’s new?Accelerated hydrogen peroxide surface disinfectant now available has no SDS hazard warnings, cleans and disinfects in 30 seconds to one minute. It is benign for the environment; noncorrosive; surface compatible. This is not the product that you buy in the brown bottle in the drugstore. This has been reformulated to be used as a highly safe and effective surface disinfectant in the healthcare field. This product is not considered hazardous by OSHA Hazard Communication Standard (29 CFR 1910.1200. You do not have to clean first then reapply. Just wipe once.
When we look at the advantages, it seems perfect. But then look at the expense. It is more expensive but If it has a faster kill claim, requiring no reapplication before it dries, that is a plus. What about the TB kill time? Remember that we are no longer concerned about killing the TB, just killing the pathogens that are viruses and that happens in a minute or less. This is a product that has no hazard warnings on its safety data sheet. It is gentle on all of your surfaces. The odor is not offensive. You can use this for all your surfaces including operatory patient chairs and equipment. By not needing to change to different products, you are increasing your efficiency and in the long run, you are saving money. Consider asking your dental supply rep for the accelerated hydrogen peroxide product. Better yet, ask for the one that is only 0.5% hydrogen peroxide. It has a faster kill claim and is easier on your hands than the other hydrogen peroxide that turns your hands white; smells better too. Yes, I know that you use wipes sometimes without gloves. I have done it myself if the surface is not contaminated. These products actually do not require personal protective equipment to use, but you should wear gloves if you are cleaning potentially infectious material when turning over an operatory. The wipes available today are very wet unlike the ones in the past so I recommend only wipes to be used in operatory cleanup. I do not advocate spraying chemicals of any kind to expose healthcare personnel to respiratory inhalation.
Candida auris (C. auris) is an emerging invasive, multidrug-resistant fungus. Many disinfectants used in healthcare facilities may not be effective against C. auris, despite claims about its effectiveness against C. albicans or other fungi. It is found and transmitted in hospitals and nursing homes. I have lectured for AzDA in the past about a 0.5% hydrogen peroxide disinfectant product that is safe and effective and now it can also kill C. auris in one minute. See Dr John Molinari: Environmental Surface Cleaning Investigation: https://www.youtube.com/watch?v=hGP4zlTLh78 to show how Optim1, an accelerated hydrogen peroxide, works compared with a Quat and an alcohol. This is now the only category of disinfectant that I recommend.
KAY’S TWO CENTSWhen I first started helping my husband in his dental practice, as an infection control nurse, I knew virtually nothing about disinfectants and sterilizers, and I found that my peers who worked in the hospitals did not either. Housekeeping was responsible for cleaning and “Central Supply” handled processing and sterilization. I set out to find out what we needed to do, and I was shocked! Dental instruments were cleaned in an ultrasonic, sterilized in stainless steel cylinder cages and then sorted out and placed back in the drawer in the operatory. What could not be sterilized was placed in a blue liquid, a Quat, to be disinfected. Later research determined that the liquid not only did not disinfect, but large numbers of germs also grew in it! Thankfully we can safely care for patients and not expose staff to harmful chemicals. Now in hospitals, nursing is required to disinfect many areas daily or more often in the patient’s unit to prevent transmission of disease to other patients. Processing of reusable items is performed in a Central Processing Department that is closely monitored and managed by skilled workers who now have their own organization and certification process. The CDC now recognizes that Dentistry is on the same level as hospitals as healthcare providers and recommendations reflect that. With the exception of dental schools, dental practices are still responsible for processing and sterilization. The OSHA toolkit offered online on AzDA’s website provides extensive information on how to process and sterilize which includes tools for documentation to prove CDC recommendations are being met. What is the difference between OSHA and the CDC? OSHA law must be followed, and CDC provides standards of care that should be followed. Both should be carried out to avoid risk management issues. It is the 21st century and it is much easier than ever before to determine what caused a patient’s infection. In fact, in an epidemiological investigation regarding a bloodborne pathogen one of the questions that may be asked is “have you recently had dental work?