Aerosol generating procedures in dentistry

June 30, 2020

One of the most critical components of a dental procedure is the use of aerosols. The smallest of them can be fatal and hazardous in the dental operatory. So why allow aerosols in the first place?

There are two types of particles produced during a dental procedure. If these particles are more than 50 micrometers in diameter, they are a part of a "splatter," which cannot thrive in air for a prolonged period of time. The smaller and the more fatal ones fall under the category of "aerosols" which can be hazardous to any individual within the dental operatory. These aerosols can cause major airborne infections by getting lodged in the lungs or any other vital organs of the body.

During a dental treatment, the risk of getting an airborn infection comes from three sources: the dental instrumentation, saliva and the site of contamination. In any routine dental procedure, these three factors are easily violated and lead to or enhance the formation of aerosols. We take a look at how the most common dental procedures lead to the formation of aerosols.

Aerosol generating procedures, also known as AGP, are using the dental turbine, which uses air to generate rotations and water to cool it off, ultrasonic scaling, 3 in 1 dental syringe, air polishing and piezo handpieces.

Ultrasonic scaling

Scaling is a treatment which involves cleaning the teeth surfaces with the help of an ultrasonic or sonic device. If a dentist uses these devices without a constant stream of water coolant, the sonic waves will harm the surface of the teeth. Hence, the sonic waves and the pressurized water jet leads to the formation of aerosols. Since this procedure takes place in the oral cavity, the pathogens present in the saliva, plaque and surrounding tissues will be a part of the aerosol composition. Moreover, root planning procedures, in which the scaler is moved below the gumline might also see the incorporation of blood products within the aerosol. Overall, scaling is one of the most  common procedures that can cause an airborne infection. However, the this aerosol contamination can be reduced by over 90% if a suction with a high volume is used.

Air Polishing

After the scaling procedure, it is important to smoothen up the tooth surface. The most common method used is by doing so with a mechanically rotating rubber cup and a paste. But, in some cases air polishing might also be done. It is done by a device that releases a pressurized air to remove all the debris and plaque. The aerosols are developed in high numbers near the operatory site and similar to ultrasonic scaling, a high volume suction is highly recommended.

Procedures involving Air-Water syringe

Air-Water syringe is a system that is used to deliver a steady flow of air, water or both at the same time via a two-way or a three-way equipment which is attached to the dental chair. The use of the air-water syringe (also known as 3 in 1 dental syringe) is routinely done while restoring teeth, performing root canal treatments, cleaning teeth, etc. The water released from this device comes through a water line that is connected to the dental chair. This water line is a hub for many microorganisms which can easily find their way to the oral cavity through the air-water syringe. Moreover, it is important to regularly sterilize this syringe since it gets placed in multiple oral cavities.

Procedures involving Air Turbine Handpiece / Air Rotor

The dental drill is known to all. This device is used for removing cavities, preparing the tooth for receiving a crown, polishing the tooth, trimming and shaping various dental materials, etc. This device generates a high quantity of aerosols but the risk of infection can be minimized if a rubber dam is used. This is a barrier like instrument that singles out the tooth/teeth of concern and shuts down the rest of the oral cavity from getting infected.

Aerosols are an occupational hazard for the dentist. Even if a dentist wears a protective equipment during a routine scaling procedure, the risk of being infected with an airborn particle lingers even after 30 minutes of the completion of the procedure. Moreover, apart from the sustainability of these droplets in the air, they also travel at distances ranging between 2 metres to 20 feet. If a virus or a bacteria gets aerosolized, it can very well be the source for tuberculosis, influenza, Legionnaires, SARS or the current wildfire, COVID-19.

It is important to note that there is no single method that can eliminate the risk of getting infected with aerosols from dental procedures. However, the use of rubber dam, suction devices, rinsing with antiseptic mouthwashes before the procedure, wearing proper equipments, etc are some of the precautions that can be taken in the dental operatory to reduce the chances of contamination. Additional precautions, even though expensive, includes the use of High-Efficiency Particulate Air (HEPA) filters and UV treatment of ventilation system in the dental room.

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