De-risking dentistry: Quantifying aerosols associated with routine dentistry to inform mitigation technology and operating practices

该项目汇集了多相流方面的国际领先专业知识，与关键利益相关者合作，以制定证据，支持在新冠肺炎疫情下安全提供英国牙科护理的新协议。气溶胶生成程序（AGPs）在牙科中普遍存在，这是由于在仪器期间使用空气和水的混合流作为冷却剂。再加上有证据表明，口腔液中含有高水平的病毒颗粒，迅速导致牙科AGP被确定为当前大流行期间的关键传播风险，所有常规的英国牙科护理都停止了。在这个项目中，我们将首先研究在最常见的牙科AGP（用于牙齿清洁的牙齿基底的高速和低速切割和超声波洁牙机）中形成的气溶胶。高速摄影结合适当的照明将用于气溶胶特性。照明角度和强度以及图像记录速度将被优化，以量化气溶胶浓度和气溶胶扩散速度以及气溶胶云可以扩散的距离。然后，将在临床相关环境中使用具有环境空气交换、外壳尺寸和反映不同护理设置的手术家具的训练人体模型进行测量。在确定当前护理实践的基线气溶胶行为后，将探索缓解措施，包括修改仪器的空气/水供应，降低切割速度，高容量抽吸参数和环境空气流量。临床专家、病毒学家、公共卫生政策研究人员和仪器制造商的直接参与将确保调查结果得到迅速考虑。

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.