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COVID-19 response

Air quality in dental surgeries

Ensuring a safe environment

Dental treatment involves a range of equipment and 'aerosol generating procedures' which can produce significant amounts of saliva/water-based aerosols in the micron and sub-micron range which present a potential transmission risk for the COVID-19 virus. Before the pandemic there had only been limited studies into the amount, size range and distance spread of dental aerosols.

During the 2020 lockdown the number of dental procedures was drastically reduced, resulting in an increase in the proportion of extractions and the number of prescriptions for antibiotics. As dentists in England resumed a more normal service, the guidance was to introduce a ‘fallow time’ between patients based on the ventilation conditions in the surgery in order to allow the aerosol particles to dissipate. Dental practices struggled to meet demand, and the fallow time between patients reduced the number of appointments each day. In addition, the cost of PPE for treating every patient had increased significantly. There was a need to increase the number of patients treated both for national dental health and to help make dental practices financially viable.

Mydentist, part of the IDH group, is the largest dental provider in Europe and had been in discussions with NPL before the COVID-19 situation about ventilation in dental surgeries. However, in preparation for reopening dental practices for routine treatments, discussions focused on ensuring the safety of clinics for both practitioners and patients. Mydentist asked NPL to perform measurements in a working dental surgery to detect and measure the aerosols produced by a variety of dental procedures and record how they changed over time. NPL used a laboratory optical particle counter instrument to take measurements and compare them with the background levels.

This feasibility study indicated that there was little or no detectable increase in the concentration of aerosol particles for the majority of the ‘aerosol generating procedures’ carried out by dentists. Aerosols were being effectively captured and reduced by the use of good practice mitigation techniques, such as the high-volume suction tool and rubber 'dams'. This information, along with findings from Newcastle University, was presented to the Scottish Dental Clinical Effectiveness Programme (SDCEP) and helped them make recommendations on reducing fallow times and taking aerosol mitigation procedures.

NPL have now performed a more detailed study with BOFA and mydentist under the Measurement for Recovery scheme, taking measurements in two dental surgery environments, with varying instrument types and procedures in order to provide definitive advice. All of the information from these tests was shared widely across the dental profession and dental research community, and it showed the benefit of a localised extraction system, situated close the patient, to remove generated aerosol in two handed dental procedures.

NPL also worked with suppliers of UVC lamps to understand their role in enhancing sterilisation during the fallow time.

If you would like to discuss further, please contact us.

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Impact during COVID-19

  • Collected data to establish safe operational procedures
  • Facilitated the resumption of dental services to meet demand
  • Helped dentists to return to safe and commercially viable operation  
  • Applied air quality monitoring knowledge and experience to dental environment 

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