Aerosol extractor in dental offices, how to operate safely

Aerosol aspiration is now an indispensable practice

Following the appearance of the coronavirus, the problem of controlling the risk of infection caused by the aerosol produced by the turbines used for many therapeutic maneuvers in the dental field has returned to the foreground for dentists.  It is known that for those who work on the patient, be it dentistry or hygienist, there are a number of biological risks that arise from so-called “aerosol pollution” or derived from the use of rotating and ultrasonic instruments that remove solid material from the operating field, thus creating a potentially infected and contaminating mist.

Technically, an aerosol extractor is needed to prevent its spread because it spreads, through the cooling water and the air coming out of the turbines, a cloud of more than one meter in diameter containing, among other compounds, biological material, viruses, and bacteria.

The contagion danger in detail

The most topical case is definitely the one related to the COVID-19 virus which, as we know, has recently been identified several times in the saliva of infected patients. This saliva is known to play a decisive role in human-to-human transmission, and dentists with other caregivers may unknowingly operate on patients infected but not yet diagnosed with COVID-19, or those who are asymptomatic. Inhalation of airborne particles and aerosols produced during dental procedures on patients with COVID-19 is therefore a very risky situation to which dentists are directly exposed. It is therefore crucial that dentists perfect preventive strategies to avoid COVID-19 infection, focusing on patient placement, hand hygiene, and all personal protective equipment (PPE).

The suction with localized collection unique effective active solution

Considering therefore that the staff is already amply equipped of devices DPI, that is of a protection “passive” towards the biological risk, in order to ulteriorly reduce this risk of infection for the professional it becomes necessary to pass to a solution “active” means that it removes or reduces the aerosol before it reaches the PPE and potentially the respiratory tract. The technique is already used in industrial contexts to protect the respiratory tract of the operator and widely indicated by the legislative guidelines (Dgls 81/2008) and by the most efficient techniques of dust and fumes abatement. It is necessary to draw as close as possible to the source, thus avoiding the dispersion of the aerosol inside the laboratory, when then it becomes almost impossible to knock it down.

Thanks to this technology, the aerosol extractor with the mobile suction arm positioned 20-30 cm from the patient’s mouth (a distance that allows the necessary movements) is capable of conveying the dangerous volatile processing residue away from the operating area to reduce as much as possible the risk of infection of operators. The aspirated aerosol is then filtered with equipment suitable for the abatement of wet mists with final efficiency HEPA H14 99.9% and then returned to a purified environment, or conveyed outside depending on logistical and plant requirements.

What requirements should the new generation aerosol extractors have

There are already several products on the market dedicated to the suction of aerosols or fumes produced during medical operations. However, in the specific case of the risk Covid-19, it is of fundamental importance to technically address the suction and filtration in a more complete way, analyzing thoroughly all the components of this polluting “cloud”.

1. Suction power and size of the extractor: no more motors of a few watts or 30 cm boxes. The suction for the effective collection of the potentially infected aerosol must have adequate dimensions as a result of the flow rate to be sucked, our engineers recommend at least 400 mc/h.
2. Size of suction arm and hood: the small laboratory suction arms are not suitable for a large flow rate and act as a “stopper” to the purifier. The design engineers are well aware that the arm must have pipes with a 100mm diameter to suck properly and be silent. The hood must be able to suck effectively at 20-30 cm from the working area without being put right “on” the patient.
3. Pre-Classing of Wet Particles: this is a non-dry wet mist, which is why the aerosol extractor must have a first stage of wet particle separation, otherwise they arrive, directly to the absolute filter that gets ruined by getting wet and when it dries loses efficiency. Beware of systems without a collection tray to be checked periodically with possibility of discharge.
4. Professional filtration with 4 filter stages: the game gets tough and with viruses it is no longer possible to have “compact” or “easy” systems. We need multistage filtrations like those used in OR air treatment plants. Coronavirus particles are estimated to be between 0.12 and 0.16 µm in size. The filter to be used for the final stage (apart from the wet part) must be HEPA H14, able to stop 99.995% of the dangerous particles present in the aerosol.

Extractor of infected aerosol: new technical solutions designed for COVID-19 risk

It is definitely not recommended to use extractors not specifically designed for this application. Below we list three solutions that vary according to operational needs and available working spaces.

Mobile extractor on wheels with self-supporting arm, with pre-muffling of the wet part aspirated, absolute filtration HEPA H14 99,995% and arm with transparent hood with circular section. Indicative dimensions mm 510x660x780 H (without arm) Nominal flow rate 400 mc/h Weight kg 55 Power 180 Watt 220/1/50 Important requirement: the suction arm to ensure the nominal flow rate of 400 mc/h must have the pipes diameter 100mm otherwise the flow rate will be reduced and the noise will be high. Pros: Very flexible solution that allows to move the purifier in different working rooms Cons: additional footprint to be added to the ground around the operating area Click here for all the information about the mobile purifier.
Wall or ceiling extractor with pre-glare of the aspirated wet part, absolute filtration HEPA H14 99,995% and connection kit to self-supporting suction arm fixed to the ceiling or wall, with transparent hood with circular section. Dimensions indicative mm 600x700x900 H (without arm) Nominal flow rate 400 mc/h Weight kg 60 Power 180 Watt 220/1/50 Important requirement: the suction arm, to ensure the nominal flow rate of 400 mc/h, must have the pipes diameter 100mm otherwise the flow rate will be low and the noise high. Pros: No footprint on the ground, the arm “drops” from the ceiling or is extended from the wall near the operating area. Cons: Installation required for wall mounting and electrical connection to the network
Centralized plant for aerosol aspiration Solution intended for contexts where it is desired to aspirate from several units conveying in a single central suction and purification. Technically each workstation is equipped with a suction arm fixed to the ceiling, then connected to a single central suction and purification with damp condensate abatement and absolute filtration HEPA H14 99,995% Advantages: no extractor inside the operating area, ideal for designing new studios Cons: hardly applicable in retrofit, requires steps in false ceiling, masonry and important plant.

UV rays and active carbon, useless if not dangerous for the extractors

There are already some systems on the market that, however, have not been designed for the treatment of aerosol and in addition to not solving the problem of the wet part already technically addressed in this article, often propose additional filtration with UV – UVG or with activated carbon panels.

You have to pay a lot of attention to these technical characteristics because in addition to being ineffective can also be dangerous, here are the specific info:

• UV lamp inserted in the extractor in order to “kill” the Covid-19 virus as well as germs and bacteria . As widely demonstrated by the technical literature on air filtration, UV rays to be effective in sterilization must have a long exposure time and certainly not less than a second as it happens in the air passages of filters and vacuums.  Sources: Wikipedia (see “applications” under: For this reason, it is not very effective on moving air, when the lamp is perpendicular to the flow, since exposure times are drastically reduced. ) and Ministry of Health / fake news on Covid-19
• Activated carbon used with a simple filter cloth: it is useless. Activated carbons are useful and efficient for deodorization or filtration of organic solvents, to be able to work in efficiency they also need long contact times (at least a second) otherwise the pores do not have time to “absorb”. Very important, if used for wet applications such as aerosols, they can become useful materials for the aggregation of fungi and bacteria in their pores, resulting in contamination of the air expelled from the aspirator. Source: Wikipedia

Our technical staff available for collect needs, request quotes or give technical advice, simply fill in the form at the bottom of the page and you will be contacted.

Links e credits

The effect of aerosol in the dental practice – Prof. Abati

Covid-19 and dentistry, resource analysis

How HEPA filtration works