Effective Management of Dental Aerosols
Because the SARS-CoV-2 virus that causes COVID-19 can be spread through the air, the scientific world has focused on the presence of the virus in droplets and aerosols. Several studies have reported data that indicate the virus can spread long distances and remain airborne for several hours. These findings have not yet been published as peer-reviewed research; however, it is widely accepted the virus can be spread through droplets and possibly aerosols. The most studied droplets and aerosols are those produced during medical procedures, such as intubation. Whether the aerosols produced during dental procedures have a large enough viral load to be infectious has yet to be determined. At this point, until there is a study of the infectivity of dental aerosols, they must be treated as potentially infectious and controlled to the greatest extent possible.
Photo Credit: Bet_Noire / iStock / Getty Images Plus
Ultrasonic Usage
The ultrasonic scaler is one of the largest producers of spatter droplets and aerosols used in dentistry. The major component of the visible spray created by an ultrasonic scaler is the water used to keep the instrument and tip from overheating, and prevent patient discomfort or damage to the tooth. In most dental offices, the coolant water comes from an independent water supply that is routinely maintained and sanitized. Assuming the dental unit waterline (DUWL) is properly maintained, the coolant spray by itself should not be a danger to patients or practitioners, and can be discounted as a source of infectious material.
Photo Credit: Bet_Noire / iStock / Getty Images Plus
Control Contamination
Assuming recommended maintenance of the DUWL is performed and proper asepsis protocols are followed, the chief source of infectious material during ultrasonic scaling is the patient. Based on this, infection control should focus on preventing infectious material from escaping the patient’s mouth and entering the environment of the dental operatory. The use of high-level filtration of environmental air, ultraviolet air decontamination, fogging of the operatory after patient treatment, positive air flow with external exhaust, and even the use of an N95 respirator are all aimed at controlling infectious material that has escaped from the patient’s mouth.
Photo Credit: Alexander Labut / iStock / Getty Images Plus
Effectiveness of Preprocedural Rinsing
Assuming recommended maintenance of the DUWL is performed and proper asepsis protocols are followed, the chief source of infectious material during ultrasonic scaling is the patient. Based on this, infection control should focus on preventing infectious material from escaping the patient’s mouth and entering the environment of the dental operatory. The use of high-level filtration of environmental air, ultraviolet air decontamination, fogging of the operatory after patient treatment, positive air flow with external exhaust, and even the use of an N95 respirator are all aimed at controlling infectious material that has escaped from the patient’s mouth.
Photo Credit: PeopleImages / iStock / Getty Images Plus
High-Volume Evacuation
Even if DUWL maintenance and patient rinsing are standard office procedure, it is still advisable to further reduce cross-contamination risks by capturing the spray from the ultrasonic scaler before it exits the mouth. This can be done by placing a large-bore (8 mm to 10 mm inside diameter) high-volume evacuator (HVE) within 2 cm of the scaler’s working tip. Placing a large-bore HVE at this distance has been shown to reduce the amount of spatter and aerosol and the number of bacteria in the operatory by more than 93%. Visual observation indicates that placing a HVE further away from the ultrasonic tip will allow a large portion of the spatter and aerosols to escape and enter the operatory.
Photo Credit: zlikovec / iStock / Getty Images Plus
Stay Safe
Infection prevention is a matter of reducing exposure to infectious material by preventing viruses and bacteria from escaping their source and entering the environment. In dentistry, this means preventing infectious material from leaving the mouth; and in the case of ultrasonic scaling, this can be accomplished via several steps. Even with the use of preprocedural mouthrinses and HVE, it is possible that a small amount of infectious material may escape into the operatory environment. Thus, the use of the recommended COVID-19 PPE (consisting of a face shield, N95 respirator, and other protection) should be maintained. With this PPE, along with proactive measures to minimize bioburden and contain spatter and aerosols to the oral cavity, potential exposure may be reduced to the point that ultrasonic scaling is safe.
