What is aerosol generating exposure in dentistry?

February 21, 2021

The spread of COVID-19 has been a growing concern for dentists. This is one profession that is at a high risk of getting infected since they work directly inside the oral cavity. The transmission of COVID-19 through aerosols has been well-established. Almost every dental procedure requires aerosol generation and hence it becomes mandatory for dentists to triage their patients as high and low risk infection carriers.

Aerosol generation in dentistry occurs when the dental drill is used in order to remove any decay from the teeth. Ultrasonic scalers used for cleaning the teeth also utilize aerosols. These are common procedures that produce aerosols and hence are called Aerosol Generating Procedures (AGPs). However, when aerosols are produced with the patient being a source of the aerosols, it is called as AGE (aerosol generating exposure).

AGEs and AGPs are different from each other. AGEs are those that involve the coughing, gagging and sneezing of patients in the dental operatory. Based on their health status, patients can be classified under high and low risk AGEs.

Low Risk aerosol generating exposure procedures 

AGEs are lowest when the patient is simply being given oral hygiene instructions. Further, they are still harmless when radiographs or photographs of the patients are being taken. An exception here is the gag reflex that a patient can get when the radiograph of a back tooth or teeth is indicated. If the tooth or teeth simply need to be restored with a filling material, then they can be done with low risk if hand instruments (not the dental drill) are used for removal of decay. A 3-in-1 syringe is one that emits air, water or both at the push of a button. Usage of these should be minimal. The tooth or teeth that is being restored must be isolated properly in order to reduce AGE.

Dental extractions that do not require bone drilling are considered as low risk AGE procedure. If the operator uses high volume suction during cleaning of teeth, orthodontic treatment (braces), broken tooth/teeth repair, fissure sealing, then they are classified as low risk AGE.

High Risk aerosol generating exposure procedures

High risk AGEs are once that involve AGPs. Radiographs of full mouth pose a risk as it takes a longer time and the mouth remains open for a longer time. The use of 3-in-1 syringe, along with use of high speed dental drills, extraction of teeth involving bone cutting are the ones that produce a lot of aerosols. Dentures when tolerated poorly by the patients is another high risk AGE. Complex surgeries involving implant placements or involving maxillary sinus generate a lot of aerosols. Examination of soft tissues which involves clinical checkup of the throat can expose the dentist to aerosols from the patient's mouth.

When it comes to AGEs, rubber dam isolation and high volume suction is mandatory. Moreover, the operator must use FFP2 or FFP3 during these procedures. Fallow time after high risk AGEs needs to be for 60 minutes. The dentist must ensure that there is proper ventilation before carrying out a high risk AGE. In the time of COVID-19, the risk of infection transmission through high risk AGEs increases and thus the fallow time has to be more accordingly.

There are instances when emergency care is needed in the dental operatory. These patients may require cardiopulmonary resuscitation (CPR) which is yet again likely to generate airborne droplets. Additionally, intubating the airway for better respiration can also cause aerosols to be generated. Emergency protocols can lead to collection of sputum which is yet again a sign as to why AGPs must be avoided in these cases.

AGPs and AGEs need to be recognized by the dental practitioner. Based on the risk assessment, the patient is scheduled and aerosols need to be controlled accordingly. The introduction of AGEs as a separate terminology to complement AGPs has helped healthcare workers in properly setting the dental operatory to reduce the risk of infection transmission. AGEs not only put the dentist at a risk of COVID-19 transmission but also other microbial infections which use aerosols as their vehicles. Thus, AGE in dentistry needs to be understood thoroughly for the better well-being for both the patient and dentist.

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