Spray mist and aerosols are created by, for example, water cooling of high-speed dental handpieces and the use of mechanical scalers.
Aerosols are also found in the water jacket of air polishings and can also contain droplets of blood, saliva (1ml saliva contains 10 million bacteria), cooling water and microorganisms, as well as residues of amalgam, ceramic or tartar.
Practice staff inhales up to 4 microliters of aerosols every working day without using extraction.
Fine particles contain 8.8 times more viral copies than coarse particles (>5µm)
Presumably a dose of at least 500-2000 viruses is required to trigger a SARS-CoV-2 infection according to a recent study by New Scientist (2020). *
* Geddes L (2020) Does a high viral load or infectious dose make covid-19 worse? NewScientist, Magazine issue 3276, https://www.newscientist.com/article/2238819-does-a-high-viral-load-or-infectious-dose-make-covid-19-worse/; https://www.erinbromage.com/post/the-risks-know-them-avoid-them
that even patients without symptoms can be contagious?
that patients generelly are already contagious approx. 2.5 daysbefore showing symptoms?
That papilloma viruses and multi-resistant pathogens are detected in laser fumes when removing warts?
The louder and more is spoken in a room, the higher is the aerosol/particle emission.
Even when coughing and sneezing, a person emits aerosols and particles, which are additionally whirled up by air currents, e.g. when moving.
The longer and the more people are in a room, the more aerosols and particles with viruses can gather.
Therefore extracting aerosols and particles is essential before they can spread in the room.
Absenteeism of dentist and practice staff = loss of earnings and ongoing employee costs
Patients can only wear their mouth-nose-protection in the waiting room, but not during dental treatment. Measures such as antiseptic mouthwash, respirator helmets or interior ventilation systems are therefore currently used primarily to protect against aerosols in dental practices. But these do not only hinder work, they also only protect to a limited extent.
The mouthwash destroys only temporarily some of the bacteria in the mouth. After a short period of time, droplets will settle on the helmets and impair the dentist's view. Interior ventilation systems whirl up aerosols in the room and distribute them several meters.
An extraction system, on the other hand, catches the aerosols directly at the point of origin and leads them through the filters. The closer the system is to the patient, the more particles are extracted.
All Occupational safety guidelines demand to extract first, then wear as addition PPE = personal protection equipment.
Only an extraction with approved separation degree of HEPA filters in accordance with
EN 1822 guarantees best possible protection for patient, medical staff and doctor.
In case of doctors or medical staff getting sick, work in the practice can not be done properly. In the worst case, the practice could even be closed by health inspectors: avoidable costs!
In accordance with TRBA 250, DGUV guideline 109-002 (Germany)
Occupational safety guidelines regulates first extracting, then wearing personal protection equipment.
A patient‘s oral cavity releases potentially infectious aerosols and particles, which can also be respirable.
Only effective extraction and filtration in combination with cleaning and desinfecting surfaces protect from transporting viruses/bacteria from one patient to another.
- Change InLine patient filter after each patient.
- Clean protective grid after each patient in thermal disinfector.
- Clean suction hood after each patient by swab disinfection with disinfection wipes.
- Clean suction hood at the end of the work day in thermal disinfector.
“The COVID-19 pandemic has brought many changes to our daily operations at the Faculty of Dental Surgery, University of Malta. From the onset of the pandemic in March 2020, the Faculty administration embarked on reorganizing our clinic protocols in preparation when we would start clinical sessions with our students.
One of our main concerns was how to reduce potential exposure risks for our students, who are at various levels of training. Following discussions and guidance from Health authorities, the faculty introduced the TBH extra-oral extraction systems to be used for all aerosol-generating procedures. The aim was to capture at source any residual aerosol emanating from dental procedures. We have found the units to be very effective on various levels- the units are very powerful, yet without generating excessive noise. Indeed a high-speed hand piece generates more noise than the TBH units do. They are also very simple to operate.
Another benefit we observed in clinics was that the unit has helped students maintain proper posture during the dental procedures since the TBH unit precludes them from engaging in bad posture. Patients, of all ages do not mind the unit on them and some have actually remarked that it made them feel more secure. The dental nurses feel that the units do not just offer safety to the students and patients but also to themselves, as extended members to the dental team. The units require little maintenance, and are easy to clean after every patient. Weekly, the filters in the unit get replaced to ensure maximum efficiency.
To conclude we are very happy with the TBH units and highly recommend them in the dental clinic“.
Prof Nikolai Attard || BChD., MSc. (Prosthodontics), PhD (TO)
(Head, Department of Oral Rehabilitation and Community Care Faculty of Dental Surgery, University of Malta)
Make a risk evaluation: how many aerosols are created?
Taking steps to reduce aerosols in the air.
Open the window as often as possible and ensure there is enough fresh air in the room.
Use a filter and extraction system.
Wear personal safety equipment.
Clean and disinfect all surfaces properly and regularly.
Use the TBH InLine filter for even more safety and cleanliness.
Everyone produces aerosols and breathes them in. They are a mixture of solid and liquid particles. Their sizes vary from a few nanometers to several micrometers. For comparison, a human hair is 100 micrometers in diameter.
The aerosols rise and spread horizontally. Therefore, horizontal air movements increase this effect. Aerosols only slowly deposit after they have spread. In rooms without mechanical ventilation, the particles spread widely in the room and linger in the air for a long time. Aerosols spread much less in rooms with mechanical ventilation, which removes them mostly.
A mouth-nose-protection that meets the test requirements of EN 14683 primarily protects other people from their own aerosols emitted when speaking. FFP2 or FFP3 masks without valve, according to EN 149 (EN 14683) protect both the wearer and the environment.
Aerosols are smaller than droplets that are expelled when coughing or sneezing. While speaking, the particles (0.01-1,500µm in size) are leaving a person's mouth. The louder the voice, the more aerosols the speaker emits. The resulting jet of droplets and aerosols spread in the room air. One breath contains around 1,000 tiny droplets, which can occur individually or in mixture with e.g. saliva or fine dust.
Since every aerosol can contain viruses such as SARS-CoV-2, one infected person is enough to infect other people in the room. At so-called super spreader events, like for example, on the Diamond Princess cruise, one person started the wave of infections. With SARS-CoV-2, the transmission cannot only take place because of aerosols in the air, but also because of so-called droplet infection. In contradiction to droplets, aerosols stay in air for a longer time.
Since aerosols are extremely small and therefore very light, air currents constantly stir them up. The aerosols’ descent rate is very low, i.e. they remain in air for several hours at average air exchange rates in office buildings. Rooms have to have sufficient air movement, for example through regular ventilation. The more people talk and the less particles are moved in the air, the longer aerosols remain in the room’s air.
Sedimentation time (deposition time)
After 20 minutes
0,5 to 3µm
Almost completely in air
3 – 10 µm
More than 50 % in air
Can spread widely when in actuating current of people
If the activities cannot be relocated outside, sufficient room air movement must be ensured, in the best case by regular ventilation, open doors, windows and fans. Before working in a room, opening the windows for at least ten minutes is essential. The air exchange can be natural or mechanical, i.e. with ventilation and air conditioning systems. A high air exchange rate reduces the number of particles in the air. Therefore, it is suggestive to let as much outside air into the rooms as possible, i.e. for as long as possible *. People should wear mouth-nose-protection and keep a distance of at least 1.5 m to minimize the risk of spreading the coronavirus. Objects and surfaces must be disinfected, especially places that are often touched by different people, such as door handles, because transmission through so-called smear infection is also possible.
By transmitting aerosols, viruses in finest droplets of saliva reach the mucous membranes and enter the airways. The aerosol jet penetrates the room air when speaking. The aerosols spread regardless of speed, difference in air humidity, turbulence or temperature difference between the jet and the ambient air. Large particles fall down while small ones and aerosol clouds follow the room air. If the airflow in the room is inconvenient, one person can infect another one even if they are not standing next to each other.
We have created assembly instructions for you as PDF.
We have provided illustrated cleaning instructions for you as PDF.
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Telephone: +49 7082 9473-0
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TBH® GmbH - Absaugtechnik, Filtertechnik, Umwelttechnik
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Filter and extraction systems deal with a topic that is important for everyone, but can also cause confusion. Therefore, we have created a list of the most frequently asked questions exclusively for you.
Since there are many terms on our website, which may not be commonly known by everyone, we created this list of the most used words in filter and extraction technology, and their respective explanations.
Our systems are for your protection. We take care of your health, the environment and longer machine running times. Find out the reasons why filter and extraction systems are so important .