Selecting the right disinfectant

Dec. 1, 2004
I am frequently asked questions about disinfectants, particularly, "Which is the right disinfectant to use?" As hygienists, we would prefer that there is only one clear choice...

by Mary Govoni

I am frequently asked questions about disinfectants, particularly, "Which is the right disinfectant to use?" As hygienists, we would prefer that there is only one clear choice, but, in reality, there are actually many products to choose from. However, before outlining the selection criteria, it is important to clarify some common misconceptions about disinfectants.

Three types of disinfectants are commonly used in dental health care settings. High level disinfectants, also referred to as chemical sterilants or "cold sterile solutions", are meant to be used as immersion products. These are most commonly glutaraldehydes and, to a lesser extent, hydrogen peroxide compounds. In both cases, these chemicals are not designed for use on environmental surfaces, as they are toxic and potentially damaging to surfaces and equipment. Their use should be restricted to disinfecting or sterilizing reusable items that cannot be autoclaved.

Disinfectants designed to decontaminate equipment and work surfaces come in many formulations. The more commonly used compounds are phenols, quaternary or "quats", iodophors, chlorines, and alcohols. These products are then classified as low or intermediate level disinfectants, depending on the types of microorganisms that they act against. According to the Centers for Disease Control and Prevention's 2003 infection control guidelines, low level disinfectants which kill HIV and hepatitis B, are appropriate for use in most dental health care settings. However, the guidelines also state that an intermediate level disinfectant should be used when visible blood is present. An intermediate level disinfectant kills mycobacterium tuberculosis, in addition to HIV and hepatitis B. Therefore, it is advisable to use an intermediate level product on all surfaces, rather than guessing about the presence of blood. It is always preferable to err on the side of caution.

The type or brand of surface disinfectant that your facility uses may be based on a preference for formulation (e.g. phenol vs. quat), and/or other characteristics such as: compatibility with equipment and materials, lack of staining, odor and method of application. Disinfectants are available as sprayable liquids, aerosols, and pre-moistened wipes. I prefer pre-moistened wipes for their convenience, but mostly because they are not applied as a spray. Unfortunately, wipes are often not used correctly. For example, in order to avoid evaporation of the solution, the tab on the top of the dispenser must be closed after each use. Periodically, the container should also be turned upside down (with the tab closed) to allow the solution to saturate the wipes. Additionally, use one wipe (or several, depending on the amount of surface area) for cleaning, and then a fresh wipe to reapply the disinfectant.

Recently, medical researchers have linked cleaning and disinfecting sprays to a phenomenon called "occupational asthma." Continuous exposure to these chemical sprays can damage your respiratory system. The following Website is an excellent resource for information regarding this subject:

In the past, we were taught to use the "spray-wipe-spray" technique for surface disinfection. Although the phrase has changed, it is actually the same "clean first, and then disinfect" procedure currently endorsed by the CDC. Also, surfaces covered with an impervious (usually plastic) barrier do not need to be disinfected, unless the barrier has been compromised, which will result in contamination. These disposable barriers must be replaced after each patient.

Regardless of the type of product selected, make certain that the product is active against the appropriate microorganisms, as recommended by the CDC. Examine the label for mixing instructions, if appropriate; for recommended personal protective equipment during use; and for information about the expiration of the product.

Mary Govoni, CDA, RDH, MBA, is the owner of Clinical Dynamics, a consulting company based in Michigan. She is a member of the Organization for Safety and Asepsis Procedures and is a featured speaker on the ADA Seminar Series. She also writes a column for Dental Equipment & Materials magazine. She can be contacted at [email protected].