Mitigating saliva aerosol contamination in a dental school clinic

Abstract Background Transmission of COVID-19 via salivary aerosol particles generated when using handpieces or ultrasonic scalers is a major concern during the COVID-19 pandemic. The aim of this study was to assess the spread of dental aerosols on patients and dental providers during aerosol-generating dental procedures. Methods This pilot study was conducted with one volunteer. A dental unit used at the dental school for general dental care was the site of the experiment. Before the study, three measurement meters (DustTrak 8534, PTrak 8525 and AeroTrak 9306) were used to measure the ambient distribution of particles in the ambient air surrounding the dental chair. The volunteer wore a bouffant, goggles, and shoe covers and was seated in the dental chair in supine position, and covered with a surgical drape. The dentist and dental assistant donned bouffant, goggles, face shields, N95 masks, surgical gowns and shoe covers. The simulation was conducted by using a high-speed handpiece with a diamond bur operating in the oral cavity for 6 min without touching the teeth. A new set of measurement was obtained while using an ultrasonic scaler to clean all teeth of the volunteer. For both aerosol generating procedures, the aerosol particles were measured with the use of saliva ejector (SE) and high-speed suction (HSS) followed a separate set of measurement with the additional use of an extra oral high-volume suction (HVS) unit that was placed close to the mouth to capture the aerosol in addition to SE and HSS. The distribution of the air particles, including the size and concentration of aerosols, was measured around the patient, dentist, dental assistant, 3 feet above the patient, and the floor. Results Four locations were identified with elevated aerosol levels compared to the baseline, including the chest of the dentist, the chest of patient, the chest of assistant and 3 feet above the patient. The use of additional extra oral high volume suction reduced aerosol to or below the baseline level. Conclusions The increase of the level of aerosol with size less than 10 µm was minimal during dental procedures when using SE and HSS. Use of HVS further reduced aerosol levels below the ambient levels.

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Factors affecting aerosol size distribution during various dental procedures

10.1101/2021.07.30.21261399 ◽

2021 ◽

Author(s):

Shruti Choudhary ◽

Michael J Durkin ◽

Daniel C Stoeckel ◽

Heidi M Steinkamp ◽

Martin H Thornhill ◽

...

Keyword(s):

Particulate Matter ◽

High Speed ◽

High Volume ◽

Routine Care ◽

Mitigation Strategies ◽

Aerosol Size Distribution ◽

Dental Clinic ◽

Factors Affecting ◽

Dental Procedures ◽

The Impact

Objectives: To determine the impact of various aerosol mitigation interventions and establish duration of aerosol persistence in a variety of dental clinic configurations. Methods: We performed aerosol measurement studies in endodontic, orthodontic, periodontic, pediatric, and general dentistry clinics. We used an optical aerosol spectrometer and wearable particulate matter sensors to measure real-time aerosol concentration from the vantage point of the dentist during routine care in a variety of clinic configurations (e.g, open bay, single room, partitioned operatories). We compared the impact of aerosol mitigation strategies [ventilation and high-volume evacuation (HVE)] and prevalence of particulate matter in the dental clinic environment before, during and after high-speed drilling, slow speed drilling and ultrasonic scaling procedures. Results: Conical and ISOVAC HVE were superior to standard tip evacuation for aerosol-generating procedures. When aerosols were detected in the environment, they were rapidly dispersed within minutes of completing the aerosol-generating procedure. Few aerosols were detected in dental clinics, regardless of configuration, when conical and ISOVAC HVE were used. Conclusions: Dentists should consider using conical or ISOVAC HVE rather than standard tip evacuators to reduce aerosols generated during routine clinical practice. Furthermore, when such effective aerosol mitigation strategies are employed, dentists need not leave dental chairs fallow between patients as aerosols are rapidly dispersed. Clinical Significance: ISOVAC HVE is highly effective in reducing aerosol emissions. With adequate ventilation and HVE use, dental fallow time can be reduced to 5 minutes.

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The Spatial-Temporal Distribution and Control Measures Evaluation of Droplets and Aerosol Cloud in Dental Procedures

10.21203/rs.3.rs-641159/v1 ◽

2021 ◽

Author(s):

Chao Yuan ◽

Hongtao Yang ◽

Siyuan Zheng ◽

Xiangyu Sun ◽

Xiaochi Chen ◽

...

Keyword(s):

High Speed ◽

Control Measure ◽

Operation Mode ◽

Temporal Distribution ◽

High Volume ◽

Control Measures ◽

Aerosol Cloud ◽

Dental Procedures ◽

Air Purifier ◽

And Control

Abstract Background: Droplets and aerosol cloud generating procedures in dentistry can increase the risk of airborne transmission of diseases such as COVID-19. To gain insight into the diffusion of spatters and possible preventive measures, we measured the particle spatial-temporal distribution characteristic and evaluated the effectiveness of the control measures.Methods: We conducted an experiment to observe the emitted spatters obtained during the simulated dental preparation by using high-speed videography. We measured the particle size distributions by laser diffraction and preliminarily estimated its velocity. We qualitatively and quantitatively described the spatial-temporal distributions of spatters and their control measure effects. Results: Majority of the dental spatters were small droplets (diameter less than 50 μm). A large number of smallest droplets (diameter less than 10 μm) were generated by high-speed air turbine handpiece. At the oral outlet, the speed of large droplets could exceed 2.63 m/s, and the speed of aerosol clouds ranged from 0.31–2.37 m/s. The evolution of the spatters showed that the more fully developed the state, the greater the number of spatters and the wider the contamination range. When the operation mode was moved from the central incisor to the first molar, the spatter direction became increasingly concentrated, and the velocities were enhanced. Larger droplets randomly moved along trajectories and rapidly settled. The aerosol cloud tended to float as a mass that interacted with the surrounding air. The high-volume evacuation could effectively clear away most of the dental spatters. The suction air purifier could change the diffusion direction of the spatters, compress the contamination range, and control aerosol escape into surrounding air. Conclusions: Our view is that we should combine the ‘point’ control measure (high-volume evacuation) and ‘area’ control measure (suction air purifier) to reduce the scope of pollution and prevent the aerosol escape into the surroundings. The study contributes to devising more accurate infection control guidelines, establishing appropriate interventions for different oral treatments, and minimizing the spread of respiratory diseases so that we can reduce cost and achieve the best results when medical resources are limited.

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Measurement of overall uptake coefficients for HO<sub>2</sub> radicals by aerosol particles sampled from ambient air at Mts. Tai and Mang (China)

Atmospheric Chemistry and Physics ◽

10.5194/acp-12-11907-2012 ◽

2012 ◽

Vol 12 (24) ◽

pp. 11907-11916 ◽

Cited By ~ 26

Author(s):

F. Taketani ◽

Y. Kanaya ◽

P. Pochanart ◽

Y. Liu ◽

J. Li ◽

...

Keyword(s):

Aerosol Particles ◽

High Volume ◽

Chemical Conversion ◽

Ambient Air ◽

Quartz Fiber ◽

Flow Tube ◽

Ambient Particles ◽

Air Sampler ◽

Quartz Fiber Filter ◽

Uptake Coefficients

Abstract. HO2 uptake coefficients for ambient aerosol particles, collected on quartz fiber filter using a high-volume air sampler in China, were measured using an aerosol flow tube coupled with a chemical conversion/laser-induced fluorescence technique at 760 Torr and 298 K, with a relative humidity of 75%. Aerosol particles were regenerated with an atomizer using the water extracts from the aerosol particles. Over 10 samples, the measured HO2 uptake coefficients for the aerosol particles at the Mt. Tai site were ranged from 0.13 to 0.34, while those at the Mt. Mang site were in the range of 0.09–0.40. These values are generally larger than those previously reported for single-component particles, suggesting that reactions with the minor components such as metal ions and organics in the particle could contribute to the HO2 uptake. A box model calculation suggested that the heterogeneous loss of HO2 by ambient particles could significantly affect atmospheric HOx concentrations and chemistry.

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The Efficacy of High-Volume Evacuators and Extraoral Vacuum Aspirators in Reducing Aerosol and Droplet in Ultrasonic Scaling Procedures during the COVID-19 Pandemic

European Journal of Dentistry ◽

10.1055/s-0041-1739448 ◽

2022 ◽

Author(s):

Trijani Suwandi ◽

Vidya Nursolihati ◽

Mikha Sundjojo ◽

Armelia Sari Widyarman

Keyword(s):

Statistical Analysis ◽

High Speed ◽

High Volume ◽

Limited Data ◽

Dental Procedures ◽

Significant Difference ◽

Kolmogorov Smirnov ◽

Airborne Disease ◽

Better Than ◽

Smirnov Test

Abstract Objective SARS-CoV-2 can be carried by aerosols and droplets produced during dental procedures, particularly by the use of high-speed handpieces, air-water syringes, and ultrasonic scalers. High-volume evacuators (HVEs) and extraoral vacuum aspirators (EOVAs) reduce such particles. However, there is limited data on their efficacy. This study aimed to determine the efficacy of HVE and EOVA in reducing aerosols and droplets during ultrasonic scaling procedures. Materials and Methods Three ultrasonic scaling simulations were conducted on mannequins: 1. saliva ejector (SE) was used alone (control); 2. SE was used in combination with HVE; and 3. SE was used in combination with HVE and EOVA. Paper filters were placed on the operator's and assistant's face shields and bodies, and the contamination of aerosols and droplets was measured by counting blue spots on the paper filters. Statistical Analysis All data were analyzed for normality using the Kolmogorov–Smirnov test. The differences between each method were analyzed using a two-way ANOVA, followed by a posthoc test. The differences were considered statistically significant when p < 0.05 Result Using HVE and EOVA reduced aerosols and droplets better than using SE alone or SE and HVE: the posthoc test for contamination revealed a significant difference (p < 0.01). The assistant was subjected to greater contamination than the operator during all three ultrasonic scaling procedures. Conclusion The usage of HVE and EOVA significantly reduced aerosols and droplets compared with using SE solely. Using these techniques together could prevent the transmission of airborne disease during dental cleanings, especially COVID-19. Further studies of aerosol-reducing devices are still needed to ensure the safety of dental workers and patients.

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The Debate: What Are Aerosol-Generating Procedures in Dentistry? A Rapid Review

JDR Clinical & Translational Research ◽

10.1177/2380084421989946 ◽

2021 ◽

pp. 238008442198994

Author(s):

M.K. Virdi ◽

K. Durman ◽

S. Deacon

Keyword(s):

High Risk ◽

High Speed ◽

High Volume ◽

Rapid Review ◽

Slow Speed ◽

Efficient Manner ◽

Dental Patients ◽

Rubber Dam ◽

Dental Procedures ◽

Current Guidelines

Introduction: This article aims to review the current national and international dental guidance produced during the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) pandemic to identify the level of consensus on aerosol-generating dental procedures (AGDPs). The outcomes intend to encourage increased collaboration with respect to dental guidelines in relation to the SARS-CoV-2 pandemic, as well as to improve decision making and safety for dental patients and staff. Methods: This rapid review was conducted by 2 authors (MKV and KD), with the support of a third author (SD), to assess current guidelines related to dental AGDPs. This streamlined review approach allowed synthesis of data in an efficient manner in the rapidly evolving environment associated with the SARS-CoV-2 pandemic. Results: The findings identified 1) a lack of consistency in reporting which procedures were deemed an AGDP; 2) that high-speed handpieces, air-water syringes, and mechanical scalers were consistently considered high-risk AGDPs; 3) a lack of consensus on the risk of coronavirus disease 2019 (COVID-19) transmission with the use of slow-speed handpieces; 4) a general agreement, when described, that rubber dam and high-volume evacuation can significantly reduce aerosol production; and 5) a lack of consistency in reporting whether procedures constitute a low, moderate, or high risk of COVID-19 transmission. The findings are discussed in relation to the guidance and future recommendations. Conclusion: It is recommended that future published guidance should indicate the risk stratification (low/moderate/high) of each procedure/exposure in a standardized international approach. Knowledge Transfer Statement: The results of this rapid review can be used by clinicians to increase their awareness of international guidance on aerosol-generating procedures in dentistry. It will also encourage those publishing future guidance to provide an internationally standardized, risk-stratified approach to describing aerosol-generating procedures. Currently, it allows clinicians to consider aerosol-generating procedures as a risk spectrum.

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Measurement of overall uptake coefficients for HO<sub>2</sub> radicals by aerosol particles sampled from ambient air at Mts. Tai and Mang, China

Atmospheric Chemistry and Physics Discussions ◽

10.5194/acpd-12-13787-2012 ◽

2012 ◽

Vol 12 (6) ◽

pp. 13787-13812 ◽

Cited By ~ 1

Author(s):

F. Taketani ◽

Y. Kanaya ◽

P. Pochanart ◽

Y. Liu ◽

J. Li ◽

...

Keyword(s):

Aerosol Particles ◽

High Volume ◽

Chemical Conversion ◽

Ambient Air ◽

Fluorescence Technique ◽

Minor Components ◽

Flow Tube ◽

Ambient Particles ◽

Air Sampler ◽

Uptake Coefficients

Abstract. HO2 uptake coefficients for ambient aerosol particles, collected on quartz filter using a high-volume air sampler in China, were measured using an aerosol flow tube coupled with a chemical conversion/laser-induced fluorescence technique at 760 Torr and 298 K, with a relative humidity of 75%. Aerosol particles were regenerated with an atomizer using the water extracts from the aerosol particles. Over 10 samples, the measured HO2 uptake coefficients for the aerosol particles at the Mt. Tai site were ranged from 0.13 to 0.34, while those at the Mt. Mang site were in the range of 0.09–0.40. These values are generally larger than those previously reported for single-component particles, suggesting that the minor components such as metal ions and organics in the particle could contribute to the HO2 uptake. A box model calculation suggested that the heterogeneous loss of HO2 by ambient particles could significantly affect the HOx concentrations and chemistry.

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Aerosol-Generating Procedures and Simulated Cough in Dental Anesthesia

Anesthesia Progress ◽

10.2344/anpr-67-03-04 ◽

2020 ◽

Vol 67 (3) ◽

pp. 127-134 ◽

Cited By ~ 9

Author(s):

Brian Chanpong ◽

Michelle Tang ◽

Alexander Rosenczweig ◽

Patrick Lok ◽

Raymond Tang

Keyword(s):

High Speed ◽

Uv Light ◽

High Volume ◽

Protective Equipment ◽

Dental Anesthesia ◽

Increased Risk ◽

Management Procedures ◽

Dental Assistant ◽

The Face ◽

Dental Professionals

Dental professionals are at an increased risk for exposure to the severe acute respiratory syndrome coronavirus 2 with aerosol-generating procedures (AGPs), and dental anesthesia practices have additional risks due to airway management procedures. The purpose of this pilot study was to examine the extent of splatter on dental personnel that may occur with AGPs and coughing in a dental anesthesia practice. A Dentoform model was fitted into a dental mannequin and coated with Glo Germ to detect splatter during simulated dental AGPs produced with use of a high-speed handpiece, an ultrasonic scaler, and an air-water syringe, all in conjunction with high-volume suction. A simulated cough was also created using a ventilator programmed to expel Glo Germ within the velocity and volume parameters of a natural cough with dental personnel in their customary positions. A UV light was used after each procedure to systematically evaluate the deposition of Glo Germ splatter on each person. After AGPs were performed, splatter was noted on the face, body, arms, and legs of the dentist and dental assistant. The simulated cough produced more extensive splatter than AGPs; additional Glo Germ was seen on the shoes, the crown of the head, and the back of the dental personnel. Therefore, it is recommended that full personal protective equipment consistent with AGPs be used and changed between patients to reduce the risk of contamination and infection for dental personnel and patients.

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Dental Aerosol as a Hazard Risk for Dental Workers

Materials ◽

10.3390/ma13225109 ◽

2020 ◽

Vol 13 (22) ◽

pp. 5109

Author(s):

Jacek Matys ◽

Kinga Grzech-Leśniak

Keyword(s):

High Speed ◽

Dental Treatment ◽

Er:Yag Laser ◽

High Volume ◽

Low Speed ◽

Dental Procedures ◽

Dental Office ◽

Study Results ◽

Caries Removal ◽

Bacteria And Fungi

Standard dental procedures, when using a water coolant and rotary instruments, generate aerosols with a significantly higher number of various dangerous pathogens (viruses, bacteria, and fungi). Reducing the amount of aerosols to a minimum is mandatory, especially during the new coronavirus disease, COVID-19. The study aimed to evaluate the amount of aerosol generated during standard dental procedures such as caries removal (using dental bur on a high and low-speed handpiece and Er:YAG laser), ultrasonic scaling, and tooth polishing (using silicon rubber on low-speed handpiece) combined with various suction systems. The airborne aerosols containing particles in a range of 0.3–10.0 μm were measured using the PC200 laser particle counter (Trotec GmbH, Schwerin, Germany) at three following sites, manikin, operator, and assistant mouth, respectively. The following suction systems were used to remove aerosols: saliva ejector, high volume evacuator, saliva ejector with extraoral vacuum, high volume evacuator with extraoral vacuum, Zirc® evacuator (Mr.Thirsty One-Step®), and two customized high volume evacuators (white and black). The study results showed that caries removal with a high-speed handpiece and saliva ejector generates the highest amount of spray particles at each measured site. The aerosol measurement at the manikin mouth showed the highest particle amount during caries removal with the low and high-speed handpiece. The results for the new high volume evacuator (black) and the Zirc® evacuator showed the lowest increase in aerosol level during caries removal with a high-speed handpiece. The Er:YAG laser used for caries removal produced the lowest aerosol amount at the manikin mouth level compared to conventional dental handpieces. Furthermore, ultrasonic scaling caused a minimal aerosol rise in terms of the caries removal with bur. The Er:YAG laser and the new wider high volume evacuators improved significantly suction efficiency during dental treatment. The use of new suction systems and the Er:YAG laser allows for the improvement of biological safety in the dental office, which is especially crucial during the COVID-19 pandemic.

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