Dental procedures can pose a high risk of viral transmission because the tools often produce aerosols — which can contain the novel coronavirus SARS-CoV-2. New research has found that careful operation of dental drills can minimise the aerosol spread.
Conducted by Imperial College London and King’s College London, the study was published in in the Journal of Dental Research on Thursday. The results are already being included as evidence in guides for dental practices in the UK during the pandemic, Imperial College London said in a statement.
Aerosols are generated when saliva mixes with water and the air streams used in dental procedures. Now, researchers have measured and analysed aerosol generation during dental procedures and suggested changes to prevent contamination to improve safety for both patients and the dental practice workforce.
They suggest dentists avoid using dental drills that use a mixture of air and water as the abrasion coolants, and carefully select and control drill rotation speeds for those instruments that only use water as a coolant. They also identified parameters that would allow some procedures such as dental fillings to be provided while producing 60 times fewer aerosol droplets than conventional procedures.
At dental clinical rooms at Guy’s Hospital in London, the researchers examined how aerosols are generated during various procedures. They measured the aerosol generation using high speed cameras and lasers. 📣 Follow Express Explained on Telegram
They found that using air turbine drill types creates dense clouds of aerosol droplets that spread as fast as 12 metres per second and can quickly contaminate an entire treatment room. Just one millilitre of saliva from infected patients contains up to 120 million copies of the virus, each having the capacity to infect.
They tested a different type of drill, known as high torque electric micromotor, with and without the use of water and air streams. Using this drill type at low speeds, and without air streams, they found, produced 60 times fewer droplets than air turbine drill types.
Also, aerosol concentration and spread within a room depends on the positioning of the patient, ventilation systems, and the room’s geometry. It is also influenced by the initial direction and speed of the aerosol itself, which can be affected by the type of cutting instrument (burr), and the amount and type of cooling water used.
Source: Imperial College London
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