Since most dental health care workers are expected to reuse their face shields, it is important to understand how to clean and disinfect this personal protective equipment (PPE). Proper and effective cleaning is a hot topic online. Typically, the comments are off-the-cuff and anecdotal.
Last week I spent hours trying to get answers to these questions. I contacted numerous distributors and manufacturers and quite honestly there was very little consensus regarding how to care for these devices, but here is what I learned.
Plastic face shields
The actual face shield material is some type of plastic, but that is where the similarity ends. Shields are made with a variety of materials, including polycarbonate and polyethylene terephthalate (also known as PET or polyester). Some materials are more rigid than others and some shields are more scratch-resistant, prolonging the overall life of the shield. Optical clarity in a plastic shield is also critical.
Sifting through the information
One company did not have a specific cleaning protocol. This decision was based on the manufacturer not having specific clearance from the Occupational Safety and Health Administration (OSHA) about cleaning and disinfecting their specific product. Another company deems their product to be single use only and recommends the shield should be discarded after each patient use. The remaining five companies had a variety of responses including using plain soap and water, or an EPA-approved product commonly used as a hard surface disinfectant or cleaner in a dental office, or 70% isopropyl alcohol as a disinfectant.
The mere lack of information or conflicting advice is not shocking. Until this recent pandemic few dental professionals routinely wore face shields, so quite simply the conversation is a new one for most companies. Out of desperation, I sought the advice of a chemical engineer on how to safely clean a plastic device. While he is not an infection control expert, he would know how to keep the shield clean without damaging the optical properties of the plastic. Since this engineer is married to a dental hygienist, he has a vested interest in a positive outcome.
Basic cleaning and disinfecting tidbits
To avoid creating surface scratches, submerge the face shield in warm water to dislodge particulate matter. Adding a mild liquid dish, like Dawn, reduces surface tension, and allows the soapy water to evenly disperse across the surface. A soft cloth or sponge can be used to gently clean the shield. Rinse the shield in clear water and dry with a soft cotton towel or a microfiber cloth. Remember soap and water removes microbes on our hands, so it will work on your shield as well.
Some clinicians also wish to use a surface disinfectant wipe or spray, but these products can leave a visible residue, which then needs to be removed. Time also matters when it comes to disinfectant solutions. Strictly follow the specific product directions for use to ensure complete disinfection. While a quick wipe may seem efficient, the contact time must be a followed. The required wet contact time can range from thirty seconds to as long as four minutes. A 70% alcohol wipe will also disinfect and keep plastic surfaces clear, but it is critical to remove the bioburden prior to disinfecting.
Damaging a face shield
Avoid using household cleaners that contain ammonia or products formulated to clean glass surfaces. Cleaners like these have the potential to damage plastic surfaces resulting in a permanently cloudy surface. Commercial cleaners that contain any type of grit are also contraindicated, including toothpaste. Avoid using paper towels, which can create microscopic scratches.
If you are worried that a specific cleaner or disinfectant might damage your face shield it is easy to run a compatibility test. Apply a small amount of the product in an inconspicuous place on the shield, such as the edge. To avoid an oops moment, make sure the test area is out of your line of sight.
Patient eye protection
In addition to face shields, many clinicians offer patients protective eyewear or goggles. Most likely this practice will become more common. Patient eye protection can be cleaned and disinfected in the same way as our shields. Once dry, store the protective eyewear in individual zip lock bags. Patients are bound to appreciate this additional consideration.
OSHA weighs in on PPE
According to OSHA, clinical dental health care workers are deemed a very high exposure risk for COVID-19. Current guidelines include minimizing the use of dental handpieces, air water syringes, and ultrasonic dental scalers and any other aerosol-generating procedures. OSHA recommends the use of an 8 mm diameter HVAC suction systems to help capture splatter and control aerosols. In addition to a mask, a face shield is recommended for all aerosol-generating procedures on all patients considered well, and for any procedure when treating a person with suspected or confirmed COVID-19. In addition, OSHA recommends performing as many tasks as possible away from patient care areas, such as cleaning a face shield.