As you all will be well aware, there currently significant restrictions on Aerosol Generating Procedures (AGP) to avoid Aerosol Generated Exposure (AGE). It is FGDP guidance to allow for a 60 minute fallow time between patients when performing AGP. However mitigating measures, along with thorough risk assessments, and Standard Operating Procedures (SOPs) can be implemented to reduce this figure.
Let's explore these some of the options:
Rubber Dam
The use of rubber dam to reduce aerosol is nothing new to dentistry, but it's effectiveness should not be overlooked. By isolating the work area from saliva in the mouth the amount of aerosol is greatly reduced.
HVE
A high-volume evacuator is a suction device that draws a large volume of air over a period of time. This differs from a low-volume evacuator (LVE), which pulls a significantly lower volume of air. Air volume is measured in cubic feet per minute (CFM), and while both HVEs and LVEs maintain the same static vacuum pressure, the difference in air volume is due to the bore hole size, or the number of holes in the evacuator tip.
HVEs offer the best solution for controlling aerosol particles before they leave the mouth. Studies have shown that an HVE can reduce 90% to 98% of aerosols, regardless of source.1
Ian Pope from Durr Dental UK has has written for us more extensively on this subject and you can see his advice here.
Air flow
The most simple method of reducing fallow period is to simply increase the air flow in the room. The 60 minute fallow recommendation is based on a single room with 6 air changes per hour (ACH), so if your able to increase the ACH you can justify lowering your fallow period.
Opening a window is the first step into increasing air flow. If you have a single room air con system in place, turning the recirculation off so that the air is extracted will also increase ACH. The simplest and potentially most effective measure for increasing ACH is to place a large fan in front of an open window.
Air Filtration
Air purifiers that use a HEPA filter or similar are currently suggested as supplementary measures. Studies have shown that UV air purifiers are effective in killing 99.9% of airborne microorganisms including Coronaviruses, Influenza A, Tuberculosis in addition to other viruses and bacteria.
The GRU-V Air Purifier available at Dental Sky is manufactured in the UK and produces no Ozone, biocides or any chemicals in addition to having a low volume operation Click here for more information.
Cold Foggers
Cold fogging is the method of spraying a fine mist of Hypochlorous acid (HOCl), or a similar disinfectant, to remove aerosol particles in the air. The solution is poured into the reservoir of an ultra-low volume fogging machine that creates a mist (not a spray) of the solution. The machine must be able to disperse the HOCl in a particle size of 20 microns or less, so check the specs of your device before use.
However the BDA has stated that "fogging techniques (with e.g. hypochlorous acid) are not currently recommended as this has not been confirmed as effective for C-19 and the health effects e.g. respiratory issues and long-term health implications for staff are unknown." .
For more information, check out the guidelines given by the FDGP here.
References
1. Harrel SK. Contaminated dental aerosols. Dimensions of Dental Hygiene. 1(6);2003:16-20.
