Disinfectant contact times -- do they really matter?

The answer to the headline question is "yes." It is very important to be familiar with and to comply with the contact times ...

by Mary Govoni, CDA, RDA, RDH, MBA

The answer to the headline question is "yes." It is very important to be familiar with and to comply with the contact times listed on the labels of the products used to disinfect noncritical surfaces in dental treatment rooms.

The labels on EPA-registered disinfectants include several contact times, depending on the types of microorganisms that the product has demonstrated efficacy against, and the length of time to kill these microorganisms. For example, some surface disinfectants have a contact or kill time for hepatitis B virus of one to three minutes. But the tuberculocidal contact time is 10 minutes. This can be confusing to some dental team members.

The longest kill or contact time is the one that must be used since there is no way of knowing what specific microorganisms are present on clinical contact surfaces, according to the EPA and the Centers for Disease Control. This means that the surfaces should be precleaned with a cleaner or a cleaner-disinfectant, and the disinfectant must then be applied or reapplied in the case of the cleaner-disinfectant.

The surface must remain moist for the longest listed contact time. Products with 10-minute contact times may not be practical for some dental facilities since slow turnover of the treatment rooms can have a negative effect on scheduling and productivity. In addition, studies have demonstrated that surface disinfectants, especially those with high alcohol content, typically dry on surfaces within three minutes. This does not meet the recommended use guidelines for disinfectants with the contact times of four minutes or longer, unless the product is reapplied (which also may not be practical).

I recommend two methods of dealing with the dilemma of complying with contact times. The first is to use impervious barriers on surfaces, eliminating the need to clean and disinfect the surface. This makes contact times irrelevant. The second is to research surface disinfectants currently available to determine which products meet the CDC recommendations for intermediate level disinfectants, and which have the shortest contact times that have been proven to the EPA for use on labels.

Some examples of disinfectants that meet these requirements are CaviCide1™ from Sybron TotalCare™ (one minute longest contact time), DisCide Ultra from Palmero Health (one minute longest contact time), and Super Sani-Cloth from PDI (two minute longest contact time).

Other examples include Opti-Cide-3 from SciCan (three minute longest contact time) and CaviCide/CaviWipes from Sybron TotalCare (three minute longest contact time). It is important to note that new or modified products are introduced frequently, so this is not an all-inclusive list of products with shorter contact times.

Read the labels of all disinfecting products that you use in your practice. Become familiar with the types of microorganisms that the products are effective against, and the recommended use and contact times. If the product you use does not come premixed, be aware of the recommended use life for the product. The proper use of disinfecting solutions is a critical piece of the infection prevention puzzle.

Mary Govoni, CDA, RDA, RDH, MBA, is the owner of Mary Govoni & Associates, a consulting company based in Michigan. She is a member of the Organization for Safety, Asepsis and Prevention. Mary can be contacted at mary@marygovoni.com or visit www.marygovoni.com.

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