De-risking dentistry: Quantifying aerosols associated with routine dentistry to inform mitigation technology and operating practices
Lead Research Organisation:
Imperial College London
Department Name: Mechanical Engineering
Abstract
This project brings together internationally leading expertise in multiphase flows with key stakeholders working to develop evidence to underpin new protocols for safe delivery of UK dental care in the light of covid-19. Aerosol Generating Procedures (AGPs) are ubiquitous in dentistry due to mixed streams of air and water used as coolants during instrumentation. This coupled with evidence that oral fluids contain high levels of viral particles rapidly led to dental AGPs being identified as a critical transmission risk during the current pandemic and all routine UK dental care stopped.
In this project, we will first characterise aerosols formed during the most common dental AGPs, (high-speed and low speed cutting of tooth substrate and ultrasonic dental scalers used for dental cleaning). High speed photography combined with appropriate illumination will be used for aerosol characterisation. The illumination angle and strength and image recording speed will be optimised for quantification of aerosol concentration and aerosol dispersion speed and distance from the source where the aerosol cloud can disperse.
Then, measurements will be conducted in clinically relevant environments using training mannequins with ambient air exchange, enclosure size and operatory furniture reflective of different care settings. Following establishment of base-line aerosol behaviour for current care practices, mitigation steps, including modifications in air/water supplies to instrumentation, reduction in cutting speeds, high volume aspiration parameters and ambient air flow, will be explored. The direct involvement of clinical experts, virologists, public health policy researchers and instrument manufacturers will ensure that findings are rapidly considered.
In this project, we will first characterise aerosols formed during the most common dental AGPs, (high-speed and low speed cutting of tooth substrate and ultrasonic dental scalers used for dental cleaning). High speed photography combined with appropriate illumination will be used for aerosol characterisation. The illumination angle and strength and image recording speed will be optimised for quantification of aerosol concentration and aerosol dispersion speed and distance from the source where the aerosol cloud can disperse.
Then, measurements will be conducted in clinically relevant environments using training mannequins with ambient air exchange, enclosure size and operatory furniture reflective of different care settings. Following establishment of base-line aerosol behaviour for current care practices, mitigation steps, including modifications in air/water supplies to instrumentation, reduction in cutting speeds, high volume aspiration parameters and ambient air flow, will be explored. The direct involvement of clinical experts, virologists, public health policy researchers and instrument manufacturers will ensure that findings are rapidly considered.
Publications
Sergis A
(2021)
Mechanisms of Atomization from Rotary Dental Instruments and Its Mitigation.
in Journal of dental research
| Description | The characteristics of aerosols generated during typical dental procedures were quantified by using high speed cameras and lasers in dental clinical rooms at Guy's Hospital in London. The considered tools were air-turbine drills, used for teeth fillings, or ultrasonic tools, used for teeth cleaning. The results showed that Air turbine drills create dense clouds of aerosol droplets contaminated with saliva and spread as fast as 12m/s and can quickly contaminate an entire treatment room. Just one milliliter of saliva from infected patients contains up to 120 million copies of the virus, each having the capacity to infect. A different type of drill, known as high torque electric micromotor, with and without the use of water and air streams was also tested and found that using this drill type at low speeds of less than 100,000 rpm without air streams produced 60 times fewer droplets than air turbine drill types. In addition, it was found that aerosol concentration and spread within a room is dependent on the positioning of the patient, presence of ventilation systems and the room's size and 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. Understanding how to reduce the amount of aerosol generated in the first place led to suggestions that could help dentists practice more and help patients get the treatment they need. |
| Exploitation Route | The suggestions have been included in the evidence appraisal in dentistry document entitled "Rapid Review of Aerosol Generating Procedures in Dentistry", published by the Scottish Dental Clinical Effectiveness Programme (SDCEP). The results from the study have also been considered by an expert task force convened by the Faculty of General Dental Practice (FGDP (UK)) and the College of General Dentistry and published in their guide entitled "Implications of Covid-19 for the safe management of general dental practice". |
| Sectors | Education,Healthcare,Pharmaceuticals and Medical Biotechnology |
| URL | https://www.imperial.ac.uk/news/211153/coronavirus-spread-during-dental-procedures-could/ |
| Description | The suggestions of the research have been included in the evidence appraisal in dentistry document entitled "Rapid Review of Aerosol Generating Procedures in Dentistry", published by the Scottish Dental Clinical Effectiveness Programme (SDCEP). The results from the study have also been considered by an expert task force convened by the Faculty of General Dental Practice (FGDP (UK)) and the College of General Dentistry and published in their guide entitled "Implications of Covid-19 for the safe management of general dental practice". Links to these documents are provided below: https://www.sdcep.org.uk/wp-content/uploads/2021/01/SDCEP-Mitigation-of-AGPs-in-Dentistry-Rapid-Review-v1.1.pdf https://www.fgdp.org.uk/sites/fgdp.org.uk/files/editors/FGDP%20CGDent%20Implications%20of%20COVID-19%20for%20the%20safe%20management%20of%20general%20dental%20practice%202%20October%202020%20v2.pdf In addition: - Impact on Guy's and St Thomas' NHS Trust - Standard Operating Procedures - Aerosol Generating Procedures. - including infrastructural developments to the largest teaching hospital in the UK. - Protocols developed through this research was adopted by 50% of all UK dental teaching hospitals and an undetermined number of primary care settings |
| First Year Of Impact | 2021 |
| Sector | Healthcare |
| Impact Types | Societal,Policy & public services |
| Description | Guidance for International Dental practice |
| Geographic Reach | Multiple continents/international |
| Policy Influence Type | Citation in clinical reviews |
| Impact | Provided advice on how to reduce the aerosols generated from Dentral Treatments and used the suggestions of the research project |
| URL | https://oralhealth.cochrane.org/news/aerosol-generating-procedures-and-their-mitigation-internationa... |
| Guideline Title | Mitigation of Aerosol Generating Procedures in Dentistry A Rapid Review Version 1.0 25 September 2020 |
| Description | New government advice on dental practice opening during the pandemic was influnced by teh findings of the project |
| Geographic Reach | National |
| Policy Influence Type | Citation in clinical guidelines |
| Impact | Introduction of new approach for dental treatments involving fillings of teeth, which were based on the adjustment of the rotational speed of drill and supply of air and water flows identified by the current project research |
| Description | Provision of High speed cameras, optical equipment and software for performance of time dependent aerosol measurements |
| Organisation | British Endodontic Society |
| Country | United Kingdom |
| Sector | Learned Society |
| PI Contribution | We extended the initial study related to the generated aerosols from dental procedures to quantify the presence of saliva in the generated droplets through contamination with the oral fluids that were presence in the mouth of a mannequin, used during the experiments. |
| Collaborator Contribution | Financial support that allowed the performance of additional experiments in the hospital environment using the real furniture and dental equipment. |
| Impact | Contributed to the described impact on policy and safe operation of dental practices, as described in the description of he project. |
| Start Year | 2021 |
| Description | Provision of High speed cameras, optical equipment and software for performance of time dependent aerosol measurements |
| Organisation | LaVision |
| Country | United Kingdom |
| Sector | Private |
| PI Contribution | We extended the initial study related to the generated aerosols from dental procedures to quantify the presence of saliva in the generated droplets through contamination with the oral fluids that were presence in the mouth of a mannequin, used during the experiments. |
| Collaborator Contribution | Financial support that allowed the performance of additional experiments in the hospital environment using the real furniture and dental equipment. |
| Impact | Contributed to the described impact on policy and safe operation of dental practices, as described in the description of he project. |
| Start Year | 2021 |
| Description | Provision of High speed cameras, optical equipment and software for performance of time dependent aerosol measurements |
| Organisation | Photron Europe |
| Country | United Kingdom |
| Sector | Private |
| PI Contribution | We extended the initial study related to the generated aerosols from dental procedures to quantify the presence of saliva in the generated droplets through contamination with the oral fluids that were presence in the mouth of a mannequin, used during the experiments. |
| Collaborator Contribution | Financial support that allowed the performance of additional experiments in the hospital environment using the real furniture and dental equipment. |
| Impact | Contributed to the described impact on policy and safe operation of dental practices, as described in the description of he project. |
| Start Year | 2021 |
| Description | Interview for National TV programme |
| Form Of Engagement Activity | A broadcast e.g. TV/radio/film/podcast (other than news/press) |
| Part Of Official Scheme? | No |
| Geographic Reach | International |
| Primary Audience | Public/other audiences |
| Results and Impact | Interview was given by Co-I Professor Owen Addison, who is at the dentistry at Kings College, who presented the approach that was used to reduce risk of infection from Covid using the findings of the project research. The dentistry part starts at around 24:30 and is about 5 minutes long in teh following URL. |
| Year(s) Of Engagement Activity | 2022 |
| URL | https://www.bbc.co.uk/iplayer/episode/m000vls9/morning-live-series-2-episode-68 |
| Description | Presentation at event of the Aerosol and Health network at Imperial College London |
| Form Of Engagement Activity | Participation in an activity, workshop or similar |
| Part Of Official Scheme? | No |
| Geographic Reach | National |
| Primary Audience | Professional Practitioners |
| Results and Impact | Medical professionals interacted with Engineers on various areas of interest to infections. This was an exchange of knowledge through the Imperial COllege Network |
| Year(s) Of Engagement Activity | 2022 |