Dental practices have long relied on high-level disinfectant/sterilants as part of the instrument reprocessing protocol. I can remember the days of using simple quaternary ammonium compounds or "quats" that were not high-level disinfectants, but we referred to them as the "cold sterile" solution.
The use of these solutions as high-level disinfectants was banned by the Food and Drug Administration in the 1980s, and solutions that contained glutaraldehydes became the accepted cold sterile solutions.
The term "cold sterile" comes primarily from the fact that items can be disinfected at a high level or sterilized if left in the solution for the required amount of time. The types of items that are appropriately processed in these solutions are those that are heat sensitive and would be damaged by placing them in a steam autoclave, unsaturated chemical vapor sterilizer, or in a dry-heat sterilizer.
This was especially helpful in the past, as many of the plastic items that are used during procedures – such as plastic suction tips, brush handles, and cheek retractors – were not heat tolerant. Many of these items now are heat tolerant, and it should be noted that if the items can be heat sterilized, they should be.
If a practice or facility chooses to use high-level disinfectant/sterilants, there are some important things to consider. The first is which type of product to use. The most common are glutaraldehydes, such as Banicide from Pascal, Biocide from Biotrol, Cidex Plus from Johnson & Johnson Dental Products, and Procide from Metrex Research. These products have a specific use life, typically 28 days, once activated and/or put into use.
Items placed in the solution can be disinfected at a high level, meaning that most microorganisms, but not bacterial spores, are killed. This occurs in 15 to 30 minutes, depending on the product. Sterilization can occur if the items are left in the solution for the required time, typically three to six hours. Again, this depends on the product. But it is important to note that, if additional items are added to the solution during a specific time period, the timing must be restarted.
There are other, non-glutaraldehyde-containing solutions for chemical disinfection and sterilization. These include Cidex OPA from Johnson & Johnson Dental Products, Metricide OPA from Metrex, and Rapicide OPA from Crosstex. These solutions are ortho-pthaladehydes. Another non-glutaraldehyde solution is Sporox II from Sultan, which is a hydrogen peroxide solution. All of these products have been cleared by the FDA for efficacy and for use in dental settings.
Other considerations with the use of cold sterile solutions are safety issues for the dental team members and environmental hazards for disposal of the products. All glutaraldehyde and OPA products should be used in well-ventilated areas. In addition, the cover on the container with the solution and items should always be closed to prevent evaporation of the solution. This could cause an environmental hazard or decrease the effectiveness of the solution.
Items should never be retrieved from the solution without the use of chemical-resistant (utility) gloves. These solutions, as well as hydrogen peroxide solutions, can be corrosive to skin. Safety glasses should also be worn to avoid the possibility of splashing of the solution into eyes. It is also important to note that these solutions can damage metal instruments and should not be used for items that can be heat sterilized.
Some states such as California have begun to regulate the disposal of glutaraldehyde solutions. Dental practices should check with their state environmental protection agency to determine if there are special requirements for the disposal of cold sterile solutions. In addition, some products have neutralizers or inactivators that can be added to the solutions prior to disposal (pouring down the drain if allowed).
Cold sterile solutions have a somewhat decreased role in dentistry with the introduction of heat- tolerant plastics and disposable items; however, they can be useful in instrument reprocessing when used appropriately.