工程科学与技术2025，Vol.57Issue(6)：286-296,11.DOI:10.12454/j.jsuese.202300934
口腔诊室内气溶胶传播与沉降的数值研究
Numerical Simulation of Concentration Variation and Deposition of Aerosol in a Dental Clinic during Oral Cleaning
摘要
Abstract
Objective Various respiratory viruses spread through aerosol transmission.Dentists and nurses are at a high risk of infection during ultrasonic scaling procedures because of exposure to patients'respiratory secretions and the substantial aerosols generated by ultrasonic devices.At present,there is a lack of research examining the effect of different airflow velocities on aerosol generation during dental ultrasonic scaling procedures.This study develops a numerical model to simulate aerosol dynamics during scaling procedures in dental clinics under two distinct airflow veloc-ity conditions. Methods The study precisely simulated ultrasonic scaling procedures performed by one dentist and one assistant nurse,based on an actual dental clinic at West China Hospital of Stomatology,Sichuan University.First,a physical model was constructed,and a tetrahedral unstructured mesh was generated using discrete computational domains.ANSYS Fluent 20.0 software facilitated the numerical simulations,employing the Realiz-able k-ε turbulence model and the Discrete Phase Model(DPM)for transient aerosol calculations.In addition,the Discrete Random Walk(DRW)model was applied to simulate particle dispersion induced by the airflow field,and the evaporation of aerosol particles was also simulated.The numerical model encompassed the initial 30-minute aerosol release procedure and the following 60-minute post-release clearance process.The study comprehensively analyzed the temporal and spatial distribution of aerosols within the dental clinic during ultrasonic scaling under two dis-tinct airflow velocity scenarios(Scenario 1:V=0.3 m/s and Scenario 2:V=2.0 m/s).Quantitative analyses of aerosol deposition and distribution patterns across various surfaces within the clinic,particularly those frequently touched by healthcare personnel,were conducted.Finally,the spa-tial distribution of aerosols generated under the two wind speed scenarios was compared(Scenario 1:V=0.3 m/s versus Scenario 2:V=2.0 m/s).The regularity and distribution area of aerosol deposition on multiple surfaces in the consulting room,mainly those frequently touched by medical staff,were quantitatively analyzed,and the infection risks faced by medical staff under both scenarios were discussed. Results and Discussions In the dental clinic,aerosols generated during ultrasonic scaling procedures rapidly spread throughout the clinic space under both airflow velocity conditions.As the procedures progressed(Scenario 1:by the 9th minute;Scenario 2:by the 3rd minute),aerosol con-centrations remained consistently high until the treatment ended.However,with a higher airflow velocity at the inlet(Scenario 2:V=2.0 m/s),aerosol levels inside the clinic significantly decreased,showing approximately 2.46 times lower particle concentration compared to Scenario 1(V=0.3 m/s).This reduction was attributed to enhanced aerosol diffusion and accelerated sedimentation within a shorter duration.After the treat-ment concluded,aerosol clearance required approximately 30.55 minutes in Scenario 1 and 5.55 minutes in Scenario 2.These findings indicated that maintaining relatively high ventilation speeds in dental clinics was advisable during respiratory disease seasons.Both scenarios presented a high risk of exposure of dental care personnel to infectious aerosols during ultrasonic scaling procedures;therefore,strict adherence to protective equipment requirements was necessary.In Scenario 1(V=0.3 m/s),aerosol concentrations at the dentist and nurse sampling sites decreased to zero after 30 minutes,whereas in Scenario 2(V=2.0 m/s),this occurred within only 6 minutes.Aerosol deposition rates were 78.93%in Scenario 1 and 87.90%in Scenario 2,with 37.55%and 52.67%of aerosols depositing on frequently touched surfaces within the clinic,respectively.The treatment console surfaces,which were most frequently touched by dental care personnel,exhibited higher aerosol deposition rates in both sce-narios:4.65%in Scenario 1 and 8.19%in Scenario 2.Surfaces such as computers and dental chairs showed higher deposition rates under Sce-nario 2 compared to Scenario 1.Considering that airflow-induced resuspended deposits served as important sources of airborne microbes,final disinfection of these corresponding surfaces after treatments was crucial to prevent cross-infection.These results emphasized the importance of meticulous surface disinfection after dental treatments to mitigate the risk of airborne pathogen transmission in dental clinics. Conclusions Compared to Scenario 1,Scenario 2 exhibited significantly reduced aerosol concentrations and shorter clearance times,attributed to enhanced airflow dynamics that facilitated aerosol dispersion and sedimentation.Aerosol deposition rates on surfaces such as treatment consoles,computers,and dental chairs were higher in Scenario 2.Different airflow velocities influenced the peak aerosol concentration,the time to reach the peak concentration,and the aerosol clearance duration in the dental clinic.When the airflow velocity increased,the peak aerosol concentration decreased,while both the time to peak concentration and aerosol clearance duration were shortened.Regardless of the scenario adopted to control infection in the clinic,it remained essential for dental staff to maintain appropriate aerosol protection.Higher airflow velocity led to increased de-position of aerosol particles on accessible surfaces.The findings of this study provide valuable insights into how various ventilation schemes and airflow velocities influence aerosol transmission dynamics in dental care environments.These results highlight the critical importance of imple-menting effective ventilation strategies and rigorous surface disinfection protocols to mitigate the risk of airborne pathogen transmission during dental procedures,contributing to the optimization of infection control measures in similar clinical settings.关键词
口腔诊室/气溶胶/空气传播/数值模拟/计算流体力学Key words
dental clinic/aerosol/airborne transmission/numerical simulation/computational fluid dynamics分类
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万紫千红,杜龙环,王小霞,冯鑫,朱卓立..口腔诊室内气溶胶传播与沉降的数值研究[J].工程科学与技术,2025,57(6):286-296,11.基金项目
四川大学华西口腔医院探索与研发项目(RD-01-202003) （RD-01-202003）
四川省科技厅重点研发项目(2024YFFK0196) （2024YFFK0196）
