Cleaning & Disinfecting Environmental Surfaces

Cleaning is the necessary first step of any disinfection process. Cleaning removes organic matter, salts, and visible soils, all of which interfere with microbial inactivation. The physical action of scrubbing with detergents and surfactants and rinsing with water removes substantial numbers of microorganisms. If a surface is not cleaned first, the success of the disinfection process can be compromised. Removal of all visible blood and inorganic and organic matter can be as critical as the germicidal activity of the disinfecting agent. When a surface cannot be cleaned adequately, it should be protected with barriers.

Disinfection destroys most pathogenic and other microorganisms by physical or chemical means. In contrast, sterilization destroys all microorganisms, including substantial numbers of resistant bacterial spores, by heat (steam autoclave, dry heat, and unsaturated chemical vapor) or liquid chemical sterilants. Disinfection does not ensure the degree of safety associated with sterilization processes.

Environmental surfaces can be divided into clinical contact surfaces and housekeeping surfaces. Clinical contact surfaces can be directly contaminated from patient materials either by direct spray or spatter generated during dental procedures or by contact with gloved hands of dental health care personnel. These surfaces can subsequently contaminate other instruments, devices, hands, or gloves. Housekeeping surfaces (e.g., walls, floors, sinks) are not directly touched during dental treatment and carry the lowest risk of disease transmission.   

Recommendations for Cleaning and Disinfecting Environmental Surfaces

* High-level disinfectants should never be used on environmental surfaces.

Abbreviation: EPA, Environmental Protection Agency

There are three levels of disinfection: high, intermediate, and low. High-level disinfectants, such as glutaraldehyde, are used as chemical sterilants and should never be used on environmental surfaces. Intermediate-level disinfectants are registered with the Environmental Protection Agency (EPA) and have a tuberculocidal claim, and low-level disinfectant are EPA-registered without a tuberculocidal claim (i.e., hepatitis B virus and HIV label claims).

The Environmental Protection Agency regulates low- and intermediate-level disinfectants that are used on environmental surfaces (clinical contact surfaces and housekeeping). The Food and Drug Administration regulates liquid chemical sterilants/high-level disinfectants (e.g., glutaraldehyde, hydrogen peroxide, and peracetic acid) used on heat-sensitive semicritical patient care devices.

CDC does not test, evaluate, or otherwise recommend specific chemical germicides. The CDC dental guidelines [PDF-1.2M] provide overall guidance for dental health care personnel to choose from among general classes of products based on infection prevention and control principles. This guidance recommends appropriate application of liquid chemical disinfectants registered with the Environmental Protection Agency (EPA) for use in dental health care settings.

The EPA maintains a list of selected EPA-registered disinfectants.

The ability to kill Mycobacterium tuberculosis is used as a benchmark to measure how well a disinfectant can kill germs. Mycobacteria have among the highest levels of resistance of all microorganisms. Therefore, any germicide with a tuberculocidal claim is considered capable of inactivating a broad spectrum of pathogens, including less resistant organisms such as bloodborne pathogens (e.g., hepatitis B and C viruses, HIV). The use of such products on environmental surfaces plays no role in preventing the spread of tuberculosis (which is airborne).

When used correctly, commercially available disposable disinfectant wipes, cloths, or towelettes are effective for cleaning and disinfecting environmental surfaces in dental settings. Any disinfectant used in a dental setting should be registered by the Environmental Protection Agency (EPA) and be approved for use in health care settings (i.e., hospital grade). Dental health care personnel should always follow manufacturer recommendations for use of cleaners and EPA-registered disinfectants (e.g., amount, dilution, contact time, safe use, disposal). Disinfectant wipes that you can buy at the grocery store are not EPA-registered and are not recommended for use in a dental setting.

Both techniques refer to the two-step procedure used to clean and disinfect environmental surfaces. If using liquid disinfectant, the user would spray the surface with the disinfectant and wipe it using a disposable towel to clean the surface ("spray-wipe"), followed by another "spray" to disinfect the surface. When using disposable disinfectant wipes, the process is described as wipe-discard-wipe because the user uses one wipe to clean the surface, discards the wipe, and uses a second wipe to disinfect the surface. Disinfectant products should not be used as cleaners unless the label indicates the product is suitable for such use. The Centers for Disease Control and Prevention recommends following manufacturer recommendations for use (e.g., amount, dilution, contact time, safe use, disposal).  

Because of the risks associated with exposure to chemical disinfectants and contaminated surfaces, dental health care personnel (DHCP) should wear appropriate PPE to prevent exposure to infectious agents or chemicals PPE can include gloves, gowns, masks, and eye protection. Chemical- and puncture-resistant utility gloves offer more protection than patient examination gloves when using hazardous chemicals. DHCP should follow manufacturer instructions and review the manufacturer Safety Data Sheet (formerly called Material Safety Data Sheet) regarding correct procedures for handling or working with hazardous chemicals.

General-purpose utility gloves are not regulated by the Food and Drug Administration because they are not promoted for medical use. Thus, they can be washed and disinfected for reuse.

Consult the manufacturer about appropriate barrier use and disinfection/sterilization procedures for electronic equipment. In the absence of a manufacturer’s cleaning instructions, use barrier protective coverings as appropriate for noncritical equipment surfaces that are 1) touched frequently with gloved hands during patient care, 2) likely to become contaminated with blood or body substances, or 3) hard to clean (e.g., computer keyboards).

Radiography equipment such as the radiograph tube head/cone/arm and control panel should be protected with surface barriers that are changed after each patient. If barriers are not used, equipment that has come into contact with gloved hands of dental health care personnel or contaminated film packets should be cleaned and then disinfected after each patient use.

Digital radiography sensors are considered semicritical and should be protected with a Food and Drug Administration- (FDA-) cleared barrier to reduce contamination during use, followed by cleaning and heat sterilization or high-level disinfection between patients. If the item cannot tolerate these procedures then, at a minimum, it should be protected with an FDA-cleared barrier and cleaned and disinfected with an Environmental Protection Agency-registered hospital disinfectant with intermediate-level (i.e., tuberculocidal claim) activity, between patients. Because these items vary by manufacturer, refer to manufacturer instructions for reprocessing.

Carpeting and cloth furnishings are harder to keep clean than nonporous, hard-surface flooring, and cannot be reliably disinfected, especially after spills of blood and body substances. Carpeted flooring and upholstered furnishings are not recommended for use in dental operatories, laboratories, or instrument processing areas.