Important Practices for Disinfectants in Dental Clinics

These days, disinfectants are as integral to any dental practice as mouth mirrors.  But how much do you know about these chemicals? Do you know the difference between a low level and a high-level product and how to use them safely?  

This blog is a quick crash course in disinfectants in dental clinics! 

Firstly, what is the difference between the levels of disinfectants available?  What does it mean to be a low- or high-level disinfectant?  

Low-level disinfectants (LLD) destroy bacteria on a surface, as well as some fungi and viruses.  These are not effective on mycobacteria or on spores.  This level of disinfection is used for most general cleaning and disinfection in the operatory for non-critical devices. 

Intermediate-level disinfectants kill everything a LLD would, but also a wider range of viruses and fungi, as well as mycobacteria (such as TB).  A lot of the disinfectants used in a dental office are actually intermediate-level solutions when used according to the label. 

High-level disinfectants go one step further and are effective against microbial pathogens as a whole, but may not work on bacterial spores.  These are sometimes used for semi-critical items such as impression trays and occlusal mirrors, but their use is discouraged due to the dangers of the chemicals and the increased workload required to properly track their use.   

So that’s great, we now know what the different levels are used for.  But how do they work? For low- and intermediate-level disinfectants there are a few compounds we commonly see.  These are sometimes the primary active ingredient, but other times two or more active ingredients may work together: 

Alcohols work by dissolving the cell membrane of organism so that it essentially falls apart.  These work very fast but are easily inhibited by organic matter on a surface, so they are only effective on clean surfaces. 

Hydrogen peroxides use hydroxyl free radicals to attack molecules including cell membrane lipids and DNA. These are generally considered safe to use and are commonly used for various levels of disinfection. 

Phenols inhibit permeases which causes the denaturation of proteins and the lysis of the cell.  These solutions tend to be more generally hazardous to humans and should not be used on porous materials, plastics, or items that come in contact with mucous membranes. 

QUATs (Quaternary Ammonium Cations) inactivate enzymes, denature proteins, and contribute to cell lysis.  These solutions tend to have a very short shelf life and are not typically a top choice for environmental cleaning unless mixed with other compounds. 

Most disinfectant products in dental will use these in various concentrations and combinations to achieve fast and effective inactivation of organisms.  It is important to use these products properly to ensure that they are able to do their job.  Here are a few tips to make sure your disinfection practices are safe and effective! 

CHECK CONTACT TIME: The contact time, sometimes called the dwell time, is the amount of time a surface has to be visibly wet in order for the solution to effectively kill or inactivate the organisms on a surface.  Contact times vary by product, and commonly range from 1-10 minutes.  Always check your label to be sure how long your product needs!   

 USE WIPES: Use wipes rather than sprays whenever you can.  Sprays can cause surface contamination to become aerosolized, generate chemical mists in the air, and provide incomplete coverage for surfaces (only the places where the droplets touch are disinfected).  If you are having trouble getting enough solution from your wipes you can always use more at a time or wipe a surface again to prolong the contact time.  It also helps to keep those pesky lids closed 😉 

WEAR GLOVES: Remember to wear gloves when handling disinfectant products.  This is for two reasons: first, to protect your skin from constant chemical exposure, and second, to protect the wipe from oils and contamination on your skin (remember that some products are inactivated by organic matter!). 

 NEVER MIX PRODUCTS: Using two different products together can cause unwanted by-products and side effects including inactivation of the active ingredients.  Single use containers are best when choosing disinfectant products to reduce the chance of contamination and biofilm formation in the bottle. 


Remember that there is no one-size-fits-all when it comes to disinfectant products!  Choosing the right one for your needs requires thought and planning, and it is essential to ensuring your practice is safe.  Talk to a consultant to discuss what will work best for you and book a Practice Audit to ensure your team are using them effectively! 

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