Cross-infection risk induced by the emitted droplets and bioaerosols during dental procedures has challenged service providers and patients alike. The present study aims to investigate the transmission mechanism of emitted droplets during the dental atomization procedures: vibration ultrasonic scaling (vUS) and rotation high-speed drilling (rHSD) and propose the risk assessment. Computational fluid dynamics (CFD) simulation was performed, and the experimentally recorded droplet velocity and diameter distribution during the atomization procedures were defined as initial boundary conditions. The droplet transmission in the dental clinic was analyzed from the final fate (deposition, suspension, and escape) and fallow time (FT) of emitted droplets. The results revealed that the diameter threshold for the droplet deposition and suspension was $60\mu m$, and the fraction of deposited droplets would be stable at 79.5% for rHSD and 85% for vUS. The primary contamination distance was generally within 0.28 m and 0.4 m from the treatment position for the atomization procedures of rHSD and vUS, respectively. An increment of about 2% in the fraction of escaped droplets was noted when conducting the rHSD. The median of estimated FT for the atomization procedure of rHSD, 34 min, was longer than that of vUS, 30.6 min. In general, cross-infection risk during rHSD can be regarded as “higher” than vUS. The contribution of the present study can serve as guidance to decrease the cross-infection risk in dental clinics.

牙科手术期间释放的飞沫和生物气溶胶引起的交叉感染风险对服务提供者和患者都提出了挑战。本研究旨在研究牙科雾化过程中喷出液滴的传播机制：振动超声洁治（vUS）和旋转高速钻孔（rHSD），并提出风险评估。进行了计算流体动力学 (CFD) 模拟，并将雾化过程中实验记录的液滴速度和直径分布定义为初始边界条件。从喷出的液滴的最终归宿（沉积、悬浮和逃逸）和休闲时间 (FT) 分析了牙科诊所中的液滴传播。结果表明，液滴沉积和悬浮的直径阈值为$60\mu 米$, 沉积液滴的比例对于 rHSD 稳定在 79.5%，对于 vUS 稳定在 85%。rHSD 和 vUS 雾化程序的初级污染距离一般分别在 0.28 m 和 0.4 m 以内。在进行 rHSD 时，注意到逃逸液滴的比例增加了约 2%。rHSD 雾化过程的估计 FT 中位数为 34 分钟，长于 vUS 的 30.6 分钟。总的来说，rHSD期间的交叉感染风险可视为“高于”vUS。本研究的贡献可以作为降低牙科诊所交叉感染风险的指导。