What Should I Use?

“What disinfectant should we use?”  This is one of the most frequently asked questions that we receive from you at Safelink.  In my April article this year, I took you Back to Basics in infection control procedures so you can refer to that article for the areas where infection control procedures are described.  Also refer to the January 2005 article for handling of bloody items.   (Both articles can be found in JDT Unbound’s archives here.) This continues to be a problem that requires communication between the dental office and the laboratory to prevent your receipt of these items and special handling in the laboratory.  From the beginning of Safelink’s existence, this issue has been a challenge and continues to be a challenge for many of you.

Over the years, some popular disinfectants have been removed from the market for various reasons with the most recent being the discontinuance of the manufacture of Biocide.  A distributor of Biocide informed us that the reason for this discontinuance was only due to the lack of adequate sales, not a problem with the product itself.  The chemical ingredients in Biocide were phosphoric acid (75 percent) and iodine.  This product was sold in the concentrated form and in that form presented many health risks since it was a corrosive.  Not only was it a corrosive, but it left a residue that discolored walls, countertops, floors and everything else that it came into contact with over a period of time.  In spite of all that, however, laboratories liked it and even used it to immerse casts or models without pitting or other problems with the cast.  So now that it’s off the market, at least in dentistry, what are the alternatives?

I hesitate to make recommendations of specific products so will address the types of disinfectants that are most prevalent in dental laboratories.  You must decide which chemical works best in your procedures.  The first reference that I use for the selection of a disinfectant is the recommendation by the Centers for Disease Control and Prevention that you use a hospital-grade, EPA registered, intermediate level disinfectant to decontaminate items received from the dental office.  Refer to the December 2003 MMWR Infection Control Guidelines for Dentistry that are available at www.cdc.gov for the CDC’s explanation of this type of disinfectant.  To determine the contact time needed for disinfecting, the CDC recommends that you use the tuberculocidal claim so select a product that provides that information.

The most prevalent active ingredient category products at this time being used in dental laboratories are referred to as the New Generation Quat/Alcohol Technology.  These types of quaternary ammonium chloride-containing products combine with alcohol to provide a faster contact time, which seems to be one of the determining factors considered by dental laboratories to minimize the processing time in the receiving area.  Reports received by Safelink from users of these chemicals have been positive, however, you should time the disinfecting carefully and also only spray casts or models received from the dental office to avoid pitting and deterioration of the cast.  Rinse thoroughly after disinfection.  Some reports that have been published indicate that no rinsing is required, but Iíd rather stay on the cautious side and make the recommendation that you rinse after disinfection.

Phenol-based products are somewhat common in the dental laboratories.  Phenols are considered toxic and are also flammable and corrosive.  The manufacturers of these products indicate that they can cause sinus and respiratory problems as well as headaches due to overexposure.  This means that you must use them in well-ventilated areas.  Daily mixing is also recommended.   Dental laboratories that use phenolics are pleased with the results, but meeting the well-ventilated area can be a challenge since receiving areas don’t typically have exhaust systems in place at the receiving bench.

Sodium hypochlorite (bleach) is also used in some dental laboratories as well as similar products containing sodium bromide and sodium dichloroisocyanurate dehydrate.  To ensure the efficacy of these types of products, thorough removal of blood and saliva prior to disinfection with this chemical is highly recommended.  Sodium hypochloriteís instability requires daily mixing and must be stored in an opaque container to prevent exposure to light.  Other factors to consider when using these chemicals are odor (can be extremely offensive to the workers) and corrosiveness to certain metals.  The economics of using sodium hypochlorite tends to be the major factor when this is the choice in the dental laboratory.

You have many choices, so select the product that best meets your needs.  Some factors you may want to consider when making this selection are:

    * Compatibility with your materials
    * Ease of use
    * Contact time
    * Odor
    * Engineering controls (ventilation)
    * Toxicity to humans
    * Personal protective equipment required
    * Label claims by manufacturer
    * Testing and approval by EPA or FDA

This is my disclaimer that I do not recommend any of the above chemicals nor is my intention to limit your use to these types of chemicals.  There are many products on the market and any omission or reference to any product by me in this article is not an indication that you shouldn’t evaluate it and consider it for your use.  The information provided here is simply to provide you some simple guidelines for selection of the chemicals that will work best for you.