Aerosol Generating Procedures and Associated Control/Mitigation Measures: A position paper from the Canadian Dental Hygienists Association and the American Dental Hygienists’ Association
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* Abdulrahman Ghoneim
* Diego Proaño
* Harpinder Kaur
* Sonica Singhal

## Abstract

**Background** Since the outbreak of COVID-19, how to reduce the risk of spreading viruses and other microorganisms while performing aerosol generating procedures (AGPs) has become a challenging question within the dental and dental hygiene communities. The purpose of this position paper is to summarize the existing evidence about the effectiveness of various mitigation methods used to reduce the risk of infection transmission during AGPs in dentistry.

**Methods** The authors searched six databases, MEDLINE, EMBASE, Scopus, Web of Science, Cochrane Library, and Google Scholar, for relevant scientific evidence published in the last ten years (January 2012 to December 2022) to answer six research questions about the the aspects of risk of transmission, methods, devices, and personal protective equipment (PPE) used to reduce contact with microbial pathogens and limit the spread of aerosols.

**Results** A total of 78 studies fulfilled the eligibility criteria. There was limited literature to indicate the risk of infection transmission of SARS-CoV-2 between dental hygienists and their patients. A number of mouthrinses are effective in reducing bacterial contaminations in aerosols; however, their effectiveness against SARS-CoV-2 was limited. The combined use of eyewear, masks, and face shields are effective for the prevention of contamination of the facial and nasal region, while performing AGPs. High volume evacuation with or without an intraoral suction, low volume evacuation, saliva ejector, and rubber dam (when appropriate) have shown effectiveness in reducing aerosol transmission beyond the generation site. Finally, the appropriate combination of ventilation and filtration in dental operatories are effective in limiting the spread of aerosols.

**Conclusion** Aerosols produced during clinical procedures can potentially pose a risk of infection transmission between dental hygienists and their patients. The implementation of practices supported by available evidence are best practices to ensure patient and provider safety in oral health settings. More studies in dental clinical environment would shape future practices and protocols, ultimately to ensure safe clinical care delivery.

Keywords
*   aerosol generating procedures
*   infectious disease transmission
*   respiratory aerosols and droplets
*   personal protective equipment
*   mouthrinses
*   SARS-CoV-2
*   COVID-19

### Position Statement of the American and Canadian Dental Hygienists’ Associations

No outbreaks of SARS-CoV-2 have been reported in dental practices or within their patient population during the pandemic. Nonetheless, despite the low risk of transmission of SARS-CoV-2 in dental settings, the possibility still exists, until proven otherwise. In light of the available evidence, the following recommendations are made to lower the risk of cross-contamination between dental hygienist and their patients while performing AGPs. Preprocedural mouthrinses are recommended to reduce the level of bacterial and viral contamination in aerosols generated albeit with very limited trial evidence after the use of AGPs for the latter. It is also recommended to use high volume evacuation with or without an intraoral suction, low volume evacuation, saliva ejector, and rubber dam (when appropriate) to reduce the aerosols generated. The combined use of protective eyewear and face shields as well as the use of ventilation and filtration systems in conjunction with aerosol scavenging systems are recommended to prevent the contamination of the facial and nasal regions when performing AGPs. Finally, in case of enclosed spaces, and with sufficient air ventilation, a fallow time of 10 minutes or less can be enough for aerosols to completely settle.

## INTRODUCTION

Aerosols can be defined as the suspension of solid or liquid particles in the air, which can be generated by either natural or anthropogenic phenomena, and may be present in different forms, such as fumes, mist, or dust.1-3 Within healthcare settings, aerosol-generating procedures (AGPs) are described as any clinical procedures that lead to the production of respiratory aerosols or liquid particles of different sizes. These respiratory aerosols or liquid particles, depending on their size, may remain airborne for long periods of time.4,5 In the wake of the Severe Acute Respiratory Syndrome (SARS) pandemic in 2003, health organizations used the term ‘AGPs’ to describe procedures that demonstrated a higher rate of infection among healthcare workers performing them.6,7 As such, for medical practices, aerosol-generating medical procedures (AGMPs) was the initial common terminology.1 Similarly, when applied to procedures specific to dental practices, the term became aerosol-generating dental procedures (AGDPs).1,4 However, AGPs is the term commonly used today in the healthcare literature, including oral healthcare.

Owing to the nature of the dental practice, the generation of spray in the form of aerosols, droplets, droplet nuclei, spatter or splatter is common during various procedures.8,9 When contaminated with saliva, these airborne particles may transmit pathogens from one individual to another through direct contact with uncovered skin or mucosa, or indirect contact via first settling on inanimate areas.10,11 Therefore, the proximity of the oral health provider and patient during routine dental and dental hygiene procedures is a concern for infection transmission.12,13 Usage of dental equipment such as handpieces (low or high speed), sonic and ultrasonic scalers, air polishers, electro-surgery units, and air/water syringes during routine procedures has been associated with significant aerosol generation, and in turn with the potential of infection transmission.5,14

There are no generally accepted terms and definitions of various forms of airborne matter and no clear delineations between terms frequently used in the field. One of the distinguishing criteria is the size of the matter particle; the smaller the size, the lighter it is, and more potential to stay airborne for a longer duration. Using the definitions developed by Micik and colleagues through their pioneering work in aerobiology in 1960s, the Centers for Disease Control and Prevention (CDC), and the World Health Organization (WHO), the various forms have been differentiated as follows:

*   *Splatter:* Mixtures of airborne particles (air, water and/or solid) greater than 50 microns (μm) in diameter, which is visible to the naked eye. These particles are often projectile in nature, and usually remain airborne for brief periods only.8,15

*   *Spatter:* Mists that contains droplets that are up to 50 μm in diameter and are usually quick to settle.4

*   *Aerosols:* Particles smaller than 50 μm in diameter.16 These are often small enough to remain suspended in the air for longer before they enter the respiratory tract or settle on environmental surfaces.8,16

*   *Droplets:* Inspirable particles larger than 5 μm in diameter.8,15

*   *Droplet nuclei:* Residue of dried aerosols ≤ 5 μm in diameter that results from evaporation of droplets.15,17 Droplet nuclei of 0.5 to 1μm in diameter are known to possess a higher risk of infection transmission in dental settings.11,16

Research in the past suggests that some diseases are known to spread via aerosols containing a variety of respiratory pathogens8,9,18, including measles, influenza, and mycobacterium tuberculosis.18–20 With the advent of COVID-19 pandemic, its spread through aerosols was a big question and dentistry being recognized as an aerosol generating profession, the importance of infection control and aerosol reduction in dental settings had become a crucial concern.11,14 It is important to note that evidence demonstrating the risk of transmission of COVID-19 in dental settings remains limited and is still being explored.14,18 A recent study by Rafiee et al. found that majority of operators’ aerosol exposure came from other sources than the patients’ saliva and nasal fluids suggesting a low risk of cross-contamination between operators and their patients in dental settings.21 It is also worth noting that while sneezing, coughing, and even talking can generate respiratory droplets of various sizes, and can cause the spread of viral infections22, this paper only focuses on the evidence of disease transmission via aerosol generating clinical procedures in dental settings.

The need for better understanding of Coronavirus transmission via AGPs in dental settings has been continuously recognized over the last three years, as dental hygiene care has experienced major disturbances in North America due to provincial and state restrictions placed on AGPs in oral healthcare settings. This prompted the exploration of the effectiveness of various methods of aerosol mitigation to control and minimize the risk of disease transmission when performing AGPs. As a result, there has been an influx of evidence advising on this topic with varying degrees of quality, contextual setting, study design, and methodological limitations. This outpour of knowledge has outpaced clinicians’ ability to keep up with the current evidence on how to conduct AGPs in the safest manner possible. Finally, with most regulatory bodies lifting the COVID-19 mandated restrictions, many dental hygienists are still uncertain about the best practices that support safe care delivery.

This position paper aims to provide dental hygienists with timely, high-quality evidence based on scientific literature about infection control and disease transmission related to AGPs. The target audience will include but not just limited to dental hygienists practicing in clinical, public health, and educational settings. In addition, the information presented in this position paper will be essential for policymakers, regulators, healthcare provider organizations, clinicians, and the public to understand the considerations for AGPs in dental hygiene practice in accordance with infection prevention and control practices.

## METHODS

Through a collaborative partnership with the Canadian Dental Hygienists Association (CDHA), the American Dental Hygienists’ Association (ADHA), an ad-hoc AGPs Steering Committee, and the consulting team, the objectives of the research project were developed to synthesize information on AGPs that will inform dental hygiene practices. The research questions that dental hygienists would potentially be interested in knowing the answers to include the following questions: the risk of infection transmission associated with conducting AGPs, types and effectiveness of preprocedural mouthrinses to reduce the microbial load of aerosols generated through AGPs, the effectiveness of dental evacuation systems, personal protective equipment (PPE) considerations for AGPs, operatory setups to control the spread of aerosols, and the fallow period following AGPs.

Therefore, the scope of this position paper was to address the aspects of risk of transmission, methods used to minimize the microbial count in aerosols, devices and PPE used to reduce contact with microbial pathogens, and operatory structures used to limit the spread of aerosols. Specifically, to provide information pertinent to the following research question(s) relevant to dental and dental hygiene practices with the aid of a PICO framework (Population, Intervention, Comparison, Outcome):

1.  What is the risk of transmission of microbial pathogens between clinical dental hygienists performing AGPs and their patients?

2.  Does the use of preprocedural mouthrinses reduce the count of microbial pathogens and/or the risk of infection transmission between dental hygienists performing AGPs and their patients?

3.  Does the use of aerosol scavenging systems (e.g., intra and extraoral evacuation systems, high and low volume suction systems) limit the spread of aerosols and reduce the risk of infection transmission between dental hygienists performing AGPs and their patients?

4.  What are the types and effectiveness of the personal protective equipment (PPE) used to reduce contact with aerosols and the risk of infection transmission between dental hygienists performing AGPs and their patients?

5.  What should be the operatory setup criteria to limit the spread of aerosols in dental and dental hygiene settings?

6.  What is the appropriate fallow time that allows aerosols to completely settle and reduce the risk of infection transmission between dental hygienists and their patients after performing AGPs?

### Inclusion criteria

Six databases, MEDLINE, EMBASE, Scopus, Web of Science, Cochrane Library, and Google Scholar, were searched for relevant scientific evidence published in the last ten years (January 2012 to December 2022) using the search strategy outlined in Appendix 1. Due to the fast-evolving nature of science and technology, it was decided to limit the search to this 10-year period to ensure the suitability of evidence to current practices. Literature search for the 6 predefined PICO questions was conducted between October 15 and November 15, 2022. On December 20, the search was re-run for all the questions to ensure the inclusion of any new literature. The search was limited to studies published in English. Commentaries and expert opinions were only included if no other studies of higher quality were identified according to the hierarchy of evidence. Finally, the reference lists of identified studies were also reviewed as a snowball mechanism to capture any study not identified through the original search terms.

### Exclusion criteria

Grey literature including governmental and organizational guidelines and recommendations were excluded as they may be based on jurisdictional, political, and regulatory approaches rather than scientific. Conference abstracts, and media articles were also excluded.

### Identification, screening, and inclusion of studies

Search results were imported into Covidence software and de-duplicated prior to review.23 Three reviewers, Abdulrahman Ghoneim, Diego Proaño, and Harpinder Kaur independently reviewed titles and abstracts using a screening form developed by the consulting team and approved by the AGPs Steering Committee. If the abstract was not available, the source was included for full-text review. The full texts of the remaining publications were retrieved and screened by the three reviewers using a standardized screening checklist. Any uncertainties related to study selection were resolved through discussion with the research supervisor (Sonica Singhal).

For each question, the research output was reviewed by the assigned reviewer along with the research supervisor. All reviewers and the research supervisor underwent a calibration exercise using 5% of articles from the initial search, and again after the final search using Cohen’s kappa coefficient. The average interrater reliability score was 0.73 indicating a substantial level of agreement between reviewers.

### Data extraction, quality appraisal, and synthesis plan

A data extraction form was used to populate pertinent information from each data source (i.e., article). Information was categorized to answer questions relevant to any dental setting. Since the scope of this position paper is to explore the breadth of the evidence related to the proposed questions, a quality appraisal of the full-text articles was not conducted. Finally, the consulting team utilized the Covidence software, which is recommended by the Cochrane network, to organize sources and synthesize data.23

## RESULTS

*Q1: What is the risk of transmission of microbial pathogens between clinical dental hygienists performing AGPs and their patients?*

The search retrieved 467 studies related to this question. After removing duplicates and irrelevant studies, eight were included in the final analysis. Three were systematic reviews24–26 and the remaining five27–31 were experimental in nature. Figure 1 outlines the PRISMA flowchart and Table I (Appendix) outlines the characteristics of the articles identified to answer this question. The main modes of transmission of SARS-CoV-2 in dental settings are aerosols, respiratory droplets, and close interpersonal contact (<1m).24,29,30 In fact, airborne transmission is the dominant route of transmission for SARS-CoV-2.29 The common AGPs include prophylaxis with ultrasonic scaler and polishing; periodontal treatment with ultrasonic scaler; any tooth preparation with high or low speed handpieces; direct and indirect restoration and polishing; cementation of crown or bridge; mechanical endodontic treatment and surgical implant placement.24,30 An experimental study by Baldion et al.30 developed a risk prediction model by assessing the settlement of particulate matter generated during dental procedures performed on manikins. The factors associated with greater risk of particle settlement were: a distance of less than 78 cm from the manikin head, inadequate ventilation, and use of high speed handpieces.30 In terms of particle size, it was found that most settled particles produced during AGPs ranged from 1-5μm. However, it is important to keep in mind that authors limited their analysis to settled particles in 30 minutes setting time. Therefore, smaller particles that require more time to settle, and likely to settle farther, were not considered in this analysis.

![Figure 1.](http://jdh.adha.org/https://jdh.adha.org/content/jdenthyg/98/1/6/F1.medium.gif)

[Figure 1.](http://jdh.adha.org/content/98/1/6/F1)

Figure 1. 
PRISMA flowchart for Q1

Next, a systematic review24 conducted in 2020 attempted to look at documented cases of transmission within different dental settings worldwide. It demonstrated that there was not adequate evidence regarding the actual cases of infection transmission among both patients and dental care providers while delivering care. Similarly, another systematic review from 2021 corroborated the lack of sufficient evidence relating to transmission rates of SARS-CoV-2 in dental settings.25 Additionally, a cross-sectional survey conducted among 51 hospitals in Japan in 2022 suggested that COVID-19 clusters were unlikely in both dental and oral surgical care settings especially when appropriate protective protocols were implemented.29 Also, a yearlong retrospective cohort study showed that the risk of contracting SARS-CoV-2 among dentalcare providers was considerably low.31 It was also implied that this lower number can be attributed to the intensive precautions and preventive measures taken before and during patient care.

A study from 2021 indicated that even in the absence of evidence of direct SARS-CoV-2 transmission through AGPs in dental environment, the possibility still exists; therefore, oral healthcare providers should not consider any in-office procedure risk-free.28 More recently, a systematic review conducted by Al-Moraissi et al. found that dental, maxillofacial, and orthopedic surgical procedures produce significant number of aerosols. However, the evidence suggesting their infectivity to transmit diseases like SARS-CoV-2 remain very weak.26 Finally, other research shows that the relative risk of infection transmission of an in-office visit can be dependent on several aspects such as the epidemiological context; geographical region; patient characteristics; and the kind of procedure being performed.24,30

Therefore, based on the infection risk prediction model for COVID-19 developed by Baldion et al., the authors classified the procedures undertaken in a dental office according to the settlement of the aerosolized particles generated during AGPs as the following:30

*   Low risk: Procedures limited to the common areas (outside the operatory) with proper social distancing (e.g., administrative tasks)

*   Moderate risk: Procedures related to cleaning, disinfection, and sterilization; and procedures conducted in a clinical environment (inside the operatory) without AGP - no use of ultrasonic or rotation instruments, or 3-way air or water spray

*   High risk: Clinical procedures conducted using aerosol generating equipment.

To summarize, oral healthcare provider should be aware of the risk of infection transmission and practice adequate preventive measures while rendering care to patients. The literature search revealed that there is limited literature to indicate the risk of infection transmission including SARS-CoV-2 among oral healthcare providers and their patients. While most studies retrieved in the search were related to modes or routes of aerosol transmission, assessment and distribution of aerosols or splatter, only a few assessed the possible risk. It should be noted that further research is therefore required to estimate the rates of infection transmission among oral healthcare providers including dental hygiene practitioners and their patients related to AGPs.

*Q2: Does the use of preprocedural mouthrinses reduce the count of microbial pathogens and/or the risk of infection transmission between dental hygienists performing AGPs and their patients?*

The search strategy yielded 789 articles for this question; after removing duplicates and irrelevant studies, fifteen suited the eligibility criteria. Figure 2 outlines the PRISMA flowchart and Table II (Appendix) outlines the characteristics of the articles identified to answer this question. Three of the studies were systematic reviews32–34 and twelve were experimental trials.35–46 The studies tested an array of antimicrobial mouthrinses including but not limited to Cetylpyridinium Chloride (CPC), Chlorhexidine (CHX), Essential Oils (EO), Hydrogen Peroxide (HP), and Povidone Iodine (PI). The AGPs tested were ultrasonic scaling, polishing, high speed handpiece for restorative preparations and debonding of orthodontic braces—the duration of the procedures ranged from 3 minutes to 90 minutes.

![Figure 2.](http://jdh.adha.org/https://jdh.adha.org/content/jdenthyg/98/1/6/F2.medium.gif)

[Figure 2.](http://jdh.adha.org/content/98/1/6/F2)

Figure 2. 
PRISMA flowchart for Q2

The included studies were homogenous both in their methodologies and results. The majority of studies (86.7%, n=13/15) assessed the effectiveness of various types of preprocedural mouthrinses on the bacterial loads found in the generated aerosols via measuring colony-forming units (CFUs) at various locations (e.g., the chest of the patient and the operators, the face shield of the operator) in the setting in which AGPs were performed.33–35,37–46 The authors compared the CFUs formed before and after performing the AGP to test the effectiveness of the tested mouthrinse. Almost all primary studies that tested the effectiveness of CHX (77.8%, n=7/9) found that rinsing with 10-15 mL of 0.12% or 0.2% CHX for 30 seconds to 1 minute before treatment significantly reduced the amount of CFUs compared to water or other rinses.35,37–41,46 Interestingly, two studies found that the use of 0.1% Octenidine and *Neem*, a novel antiseptic mouthrinse, were more effective than 0.2% chlorhexidine in reducing the bacterial load in the aerosol produced during ultrasonic scaling.44,45 Neem *(Azadirachta indica)* is a tree that grows in tropical regions such as India and is researched in the dental field for its various therapeutic effects including its anticariogenic, anti-inflammatory, and antimicrobial properties.47

Systematic reviews conducted by Marui et al. and Mohd-Said et al. corroborated those findings and suggest that the use of preprocedural mouthrinses prior to performing AGPs can effectively reduce the level of bacterial contamination of aerosols.33,34 However, Marui and colleagues reported that the included studies had high or unclear risk of selection bias, blinding, and detection bias hence they stated that the results must be interpreted with caution.33

Despite that many of the studies were published after 2019 (66.7%, n=10/15),32,34,36,38–40,42–45 only two studies assessed the impact of using preprocedural mouthrinses on viral loads, especially coronavirus, after using AGPs. First, Burgos-Ramos et al. compared the viral loads captured by portable air cleaners (PAC) with high-efficiency particulate air (HEPA) filters over 3 months in the waiting room (where patients wore face masks but did not undergo mouth rinsing), and 3 treatment rooms (where patients wore no masks but carried out 1 minute mouth rinsing with 1% H2O2) of a dental clinic in Spain.36 The authors found viral load in filters from the waiting room; however, not from the treatment rooms, where patients rinsed with 1% HP as soon as they removed the facemask and had undergone AGPs.

Similarly, Nagraj et al. conducted a systematic review with the primary objective to assess the evidence on the incidence of infection among oral healthcare providers and secondary outcome was reduction in the contamination level of the dental operatory environment.32 The authors did not come across any study to address their primary objective. In terms of the reduction in the contamination level, they could only find a few studies which assessed reduction in bacterial contamination level in aerosols, but none evaluated viral or fungal contamination.

Alternatively, several studies including systematic reviews and randomized controlled trials explored the virucidal effect of mouthrinses on the viral load, specifically, SARS-COV-2 in saliva. However, these were mere repeated measures studies that did not utilize AGPs. The explored mouthrinses had mixed results on the viral loads post use. For example, a systematic review conducted by Mohebbi et al. found that 1% PI, Listerine (EO), and CHX reduced the viral load in the saliva samples after rinsing compared to baseline, albeit with various effect rates and substantivities.48 This corroborated the findings from an earlier review conducted by Silva et al. that also demonstrated significant reductions in the salivary viral load after rinsing with PI and CPC.49 Alternatively, a systematic review conducted by Ortega et al. did not find evidence to support the use of HP to reduce the viral load of SARS-CoV-2 or any other viruses in saliva.50

However, the limitation of this body of evidence is twofold. First, they do not assess the viral load produced by AGPs, and therefore might not be informative for clinicians looking for evidence to support their practices. Second, they did not assess clinical end point outcome (i.e., cross infection between clinicians and patients, etc.) and subsequently might not translate to clinical recommendations. In other words, despite their proven effectiveness in reducing the viral load in saliva, they cannot assume the reduction of the risk of cross contamination. Therefore, to better inform the dental hygiene community about the effectiveness of tested preprocedural mouthrinses, more experimental studies need to be conducted to assess the change in viral load in the aerosol generated during procedure and more importantly, if it changes the possibility of infection transmission.

To summarize, there is substantial evidence to suggest that the use of preprocedural mouthrinses reduce the level of bacterial contamination in aerosols generated by procedures commonly performed by dental hygienists. While there is some evidence to suggest the virucidal effect of preprocedural mouthrinses, the findings are limited to studies that did not perform AGPs.

*Q3: Does the use of aerosol scavenging systems (e.g., intra and extraoral evacuation systems, high and low suction systems) limit the spread of aerosols and reduce the risk of infection transmission between dental hygienists performing AGPs and their patients?*

The search strategy yielded 934 articles. After removing duplicates and irrelevant studies, thirty-four met the eligibility criteria and were included in the analysis. Figure 3 outlines the PRISMA flowchart and Table III (Appendix) outlines the characteristics of the articles identified to answer this question.

![Figure 3.](http://jdh.adha.org/https://jdh.adha.org/content/jdenthyg/98/1/6/F3.medium.gif)

[Figure 3.](http://jdh.adha.org/content/98/1/6/F3)

Figure 3. 
PRISMA flowchart for Q3

Studies found were conducted in quite varied clinical settings; the most common was a single-chair dental operatory. More than half of the studies reviewed (n=19) were done on manikins, two without manikins but in vitro, nine observational studies using live participants, and four studies were systematic reviews, including one Cochrane review from 2020. In addition, 18 studies examined aerosol-reducing methods using intraoral devices (i.e., low-and high-volume evacuators), three compared high-volume evacuators intra-orally and extra-orally, and 13 studies examined other extraoral devices (i.e., 10 assessed extraoral suction systems, two dental chambers, and one a dental barrier).

It is relevant to note the high number of studies using manikins in the studies reviewed. The use of manikins instead of human participants could limit the extrapolation of results, however, the use of human participants could raise ethical concerns in experimental studies because of the risk of infection to the health provider, or vice-versa, performing dental AGPs.

The dental AGPs tested were commonly ultrasonic scaling or procedures using high speed handpiece as these are considered to generate the largest amount of aerosols.51–66 The duration of the AGPs mostly ranged between 5 to 10 minutes and most commonly, studies used bacterial contamination or particle counts to test aerosol mitigation effectiveness.

The studies on intraoral aerosol reducing methods almost entirely focused on assessing high-volume evacuators (HVE), which showed greater effectiveness when ultrasonic scalers were used.51,63 One study, conducted in dental offices in Italy, evaluated only low-volume evacuators (LVE),67 and found LVE to be effective in reducing the number of particles during AGPs.67 Other studies suggest that using intraoral HVE compared to LVE is more beneficial in reducing aerosol particles.56,58 In addition, if the HVE is dynamic (i.e., follows the path of the dental AGP), it is more effective in mitigating aerosol generation than static intraoral devices (i.e., that don’t follow the path of the AGP, whether HVE or LVE).63 The HVE and LVE, however, can be used in combination to yield positive results.9,21,65 As Rafiee et al. highlight, the addition of HVE to the saliva ejector produces a low number of particles during ultrasonic scaling and is, therefore, not seen as a high-risk exposure.21 Moreover, the effectiveness of HVE can be improved by using isolation adapters (i.e., with soft tissue retractors),58,66,68 or a rubber dam (when appropriate),61,65 compared to HVE alone.

Similarly, the use of rubber dam alone to limit the spread of aerosols was also identified in the literature. In the Cochrane review conducted by Kumbargere Nagraj et al., the authors found three studies that assessed the impact of the use of rubber dam compared to no use at different locations. They found that the use of a rubber dam yielded reduction in aerosol contamination 1 and 2 meters away from the mouth. However, the use of rubber dam also resulted in significantly higher presence of aerosols on the operator’s forehead, left ear, submental triangle, and occiput, emphasizing the importance of operator PPE.

In terms of the HVE characteristics, Graetz et al. suggest that the use of a suction cannula of 16 mm in diameter at a high-flow rate of ≥250 l/min provides the lowest splatter contamination values.55 In addition, Matys and Grzech-Lesniak suggest that the use of a wider customized HVE-tip to be more effective than the standard tip.58

In addition, three studies have compared the effectiveness of reducing aerosols in using HVE intra-and-extra-orally.64,68,69 As such, Ehtezazi et al. report that intraoral HVE is superior to extraoral HVE,69 while D’Antonio et al. suggest that intraoral HVE, HVE intraoral adapter, or extraoral suction devices are equally effective in preventing respirable aerosol.64 Furthermore, Choudhary et al. report that the use of an extraoral conical HVE was more effective in reducing aerosol concentration than the standard-tip HVE due to its relatively larger surface area.68

Among studies assessing other extraoral aerosol-reducing methods, ten examined extraoral suction systems,9,51,53,55,60,62,70–73 two assessed innovative chamber devices,52,74 and one examined an individual dental barrier.75 Although authors reported positive results for the chamber devices and individual dental barriers, these were isolated studies.

Some studies suggest that extraoral suction systems paired with HVE or LVE showed the greatest reduction in particle concentration, aerosol and droplet level when compared to no extraoral suction systems during dental AGPs.9,60,73,76 Also, D’Antonio indicates that pairing extraoral suction systems with local ventilation are effective in reducing aerosols in a multi-chair open clinic setting.64

In terms of the reviews examined, most were published during the pandemic (2020, 2021). The 2020 Cochrane review considered studies that assessed bacterial contamination and aerosol particle concentration, but not necessarily the risk of infectious disease transmission.77 In addition, the review reported that the included studies were of low certainty, due to the high heterogeneity in findings, risk of bias, small sample size, wide confidence intervals, and no minimal clinical importance of the difference in CFUs. Furthermore, the studies did not evaluate costs, acceptability, or ease of implementation.77 The main findings, nevertheless, highlighted the use of HVE and HVE + rubber dam when applicable.77 This finding coincides with that of Robertson et al., and the Samaranayake et al., and Deana et al. systematic reviews, that all agreed on the effectiveness of HVE on aerosol reduction.78–80 Moreover, Samaranayake et al. added that this effect depends on the suction strength, proximity to the operating site and number of HVE used as one study demonstrated that two HVEs had a greater aerosol reducing effectiveness than only one.78

To summarize, the evidence reviewed sheds light on the benefits of the use of HVE either with or without an isolation adapter, LVE saliva ejector, and a rubber dam (when appropriate), for reduced aerosol contamination. In that sense, HVE can be seen as required for oral health practitioners to use during dental AGPs, especially for dental procedures that generate the largest concentration of aerosols, such as ultrasonic scaling and high-speed drilling of anterior teeth.

*Q4: What are the types and effectiveness of the personal protective equipment (PPE) used to reduce contact with aerosols and the risk of infection transmission between dental hygienists performing AGPs and their patients?*

The search strategy yielded 370 articles. After removing duplicates and irrelevant studies, seven studies were included in the final analysis.81–87 Figure 4 outlines the PRISMA flowchart and Table IV (Appendix) outlines the characteristics of the articles identified to answer this question. Four of the identified studies were conducted in simulated settings with manikins and structured cubicles that resemble a real dental clinic.82,84–86 Three studies tested the effectiveness of conventional protective eyewear, masks, and respirators while the rest tested innovative protective devices such as Air-fed masks,82 Individual Biosafety Capsule Device (IBCD),85 rigid protective devices,86 and the Cupola.87 The outcomes assessed were bacterial contamination on eye lenses,81 facial contamination,82, bacterial filtration efficacy (BFE),83 containment of aerosols,85–87 and the viral load on the forehead and inside the mouth of an operator manikin.84

![Figure 4.](http://jdh.adha.org/https://jdh.adha.org/content/jdenthyg/98/1/6/F4.medium.gif)

[Figure 4.](http://jdh.adha.org/content/98/1/6/F4)

Figure 4. 
PRISMA flowchart for Q4

Afzha et al. found that the use of protective eyewear reduced the bacterial contamination on contact lenses compared to not using eyewear.81 After 10 minutes of high speed handpiece activity, Bridgman et al. found that 1) the use of N95 masks did not prevent nasal and oral contamination with aerosols; 2) the use of the novel air-fed mask in combination with glasses and N95 resulted in the elimination of all facial contamination; and 3) the use of air-fed mask and a sealed hood resulted in no contamination of the face, head or neck.82 Donning and doffing instruction of the Air-fed mask system are described elsewhere.82 However, it is worth noting that the authors did not mention that participants were properly fit-tested for the evaluated N-95 respirators, and only one type of N95 respirator (FFP2) was tested. Therefore, it is important to interpret the findings from this study with caution. All three studies that assessed the aerosol containing devices found reduction in the aerosol dispersion when using compared to no use. Finally, the only study that assessed viral loads found that using a face shield resulted in below-detection levels on the operator manikin’s forehead. Similarly, all surgical masks and respirators resulted in undetectable viral loads inside the operator manikin’s mouth, with or without the use of a face shield.84 Therefore, the authors suggested that the combined use of face shields and masks, regardless of the type, can prove effective in reducing the viral load on the operator’s forehead and inside their mouth to an insignificant level.

Additionally, three systematic reviews were conducted to test the effectiveness of N95 respirators versus surgical masks in reducing viral illness (e.g., Influenza and COVID-19) without performing AGPs.88–90 The study by Long et al. did not find the use of N95 respirators superior to surgical masks in terms of reducing the risk of laboratory-confirmed influenza.88 It is important to note that the ASTM (The American Society for Testing and Materials) level (Level 1, 2 or 3) of surgical masks was not specified in these studies. More recently, the Cochrane review conducted by Jefferson et al. found no evidence to suggest that medical/surgical masks offer any greater protection against viral respiratory illnesses compared to no masks although only two of the ten included studies were conducted in healthcare settings.89 The authors also did not find any additional protection when using N95/P2 respirators compared to medical/surgical masks on laboratory-confirmed influenza infection.89 On the contrary, in the systematic review conducted by Collins et al., the authors found that the use of N95 respirators was associated with fewer viral infectious episodes for healthcare workers compared with surgical masks.90 However, the high-risk biases and the limited number of studies included (n=8) suggests the need for higher quality evidence on this matter. The mixed evidence suggested by the mentioned systematic reviews highlights the uncertainty about the effectiveness of N95 respirators versus surgical masks when it comes to preventing viral infections.

Overall, there are several limitations that hinder the applicability of the findings from this evidence. First, all the studies utilized surrogate outcomes (i.e., the presence of aerosols on the body/masks etc.) rather than the clinical outcomes such as transmission of infection. Second, it is interesting to note that only two studies assessed the effectiveness of these methods for more than 10 minutes which is a closer resemblance of the real-life scenario where dental hygienist might be conducting AGPs for extended periods of time. Finally, the use of simulated settings, while useful, does not provide a similar experience as when experimented on real patients.

To summarize, despite the paucity of studies addressing this research question, the overall limited evidence suggests that the combined use of protective eyewear, masks (N-95, FFP2, or air-fed), and face shields are effective for the prevention of contamination of the facial and nasal region. Other innovative devices, such as the Individual Biosafety Capsule Device (IBCD), and the Cupola have also shown promising results in limiting aerosol contamination. However, more studies with real patients and while performing AGPs for prolonged times are necessary to establish their effectiveness.

*Q5: What operatory setups limit the spread of aerosols in dental and dental hygiene settings?*

The purpose of this research question is to assess the role of architectural or engineering controls within a dental clinic or operatory setup in limiting the spread of aerosols. Air cleaning systems or ventilation systems are considered helpful in reducing airborne transmission in indoor environments. The search strategy yielded 231 articles for this question. After removing duplicates and irrelevant studies, five were included in the analysis. Four studies were experimental in nature51,91–93 and one was a Cochrane review.77 Figure 5 outlines the PRISMA flowchart and Table IV (Appendix) outlines the characteristics of the articles identified to answer this question.

![Figure 5.](http://jdh.adha.org/https://jdh.adha.org/content/jdenthyg/98/1/6/F5.medium.gif)

[Figure 5.](http://jdh.adha.org/content/98/1/6/F5)

Figure 5. 
PRISMA flowchart for Q5

Ventilation controls can assist in the removal of air contaminants and is usually dependent on the infrastructural configuration.51,92 Filtration increases the effective air-exchange rate, and the effect of filtration devices usually depends on the distance from the source and airflow in the room.92 Ren et al. assessed the effectiveness of aerosol removal by mechanical ventilation and a portable air cleaner (PAC) with a high-efficiency particulate air (HEPA) filter in a simulated study at a dental facility.92 Aerosol accumulation was higher in rooms with poor mechanical ventilation in comparison to rooms with high ventilation, hence an inverse correlation between speed of aerosol removal and mechanical ventilation. The study concluded that using PAC in combination with HEPA filter was highly effective in reducing aerosol accumulation and thereby accelerating aerosol removal. In this case, the authors stated that only rooms with air changes greater than 15 could completely remove the aerosols by mechanical ventilation alone within the 30 min observation period in this study. Given that this might not be achieved in many dental settings, ventilation alone might not achieve aerosol removal in less than 30 minutes. Therefore, the effectiveness for PAC was noteworthy and recommended in rooms with poor mechanical ventilation.

Furthermore, one study looked at the impact of incorporating additional local ventilation systems to the existing operatory setup. Allison et al. looked at local exhaust ventilation (LEV) systems that can capture aerosols at the source and limit their dispersion.51 They studied the effect of LEV on the distribution of aerosols produced during dental procedures after adding it to the existing suction devices, while using air-turbine handpiece and ultrasonic scaler. The observations included a 90% (within 0.5 m) reduction in aerosol production from the air-turbine handpiece, and 99% for the ultrasonic scaler. Based on their experiment, they inferred that LEV reduces aerosol and droplet contamination by at least 90% in the breathing zone of the operator.

In addition to studying aerosol spread and aerosol settling time after dental procedures in an open plan clinic, Holliday R et al. also looked at impact of cross-ventilation (windows were fully opened).91 It was found that dental suction and natural ventilation are beneficial in reducing aerosol contamination. As for the layout, the authors found that the risk of aerosol migration from AGPs in an open plan clinic is likely to be minimal when the adjacent dental bays are ≥ 5 m apart.91 For other aerosol mitigation strategies, Zhu M et al. suggested the implementation of physical barriers between adjacent dental bays in a multi-chair setting (dental school environment in this case).93 The total partition height between stations was 2.5 meters and transparent plastic sheets (<1 cm in thickness) were used to supplement the original partitions (1.3 meters and made of fabric covered material). They concluded that such barriers reduced transport of aerosols to adjacent dental bays. However, it should be noted that this study did not comment on the spread of aerosol contamination.

The Cochrane review by Kumbargere Nagraj et al. included studies that previously measured the volume of contaminated aerosols in dental environments.77 One compared operative settings with air cleaning system (ACS) versus no air cleaning system, and the other compared settings with laminar air on with HEPA versus those with laminar air off to study decontamination of aerosols in air. The results for both studies estimated fewer colony forming units (CFUs) after the procedures, showing a reduction in the aerosol load. Kumbargere Nagraj et al. noted the lack of laboratory studies as one limitation and another was the inclusion of a dated studies in this review.77

The search did not yield any studies on other methods such as ionisation, use of UV light and fogging, and few studies assessed operatory design. Future research is required in this area, especially interventional studies that assess architectural or infrastructural as well as engineering controls in practice in dental environments. Some studies have described the mechanism of similar controls (like installing high efficiency air filters, increasing ventilation levels, providing negative ventilation pressure, and incorporating isolation rooms) in dental practices.93–97 However, due to insufficient evidence in terms of absolute reduction of aerosol contamination in dental operatories, they are not reported here.

To summarize, based on the studies reviewed, it can be inferred that by adopting an appropriate combination of ventilation and filtration approaches, in conjunction with aerosol scavenging systems, dental practices can limit the spread of aerosols generated by AGPs. Future studies to assess the impact of newer technologies and innovations in limiting the spread of aerosols, would be interesting as it may change the landscape of dental operatories setup.

Q6: What is the appropriate fallow time that allows aerosols to completely settle and reduce the risk of infection transmission between dental hygienists and their patients after performing AGPs?

The search strategy yielded 115 articles for this question. After removing duplicates and irrelevant studies, nine studies (3 reviews and 6 experimental studies) were included in the analysis. Figure 6 outlines the PRISMA flowchart and Table VI (Appendix) outlines the characteristics of the articles identified to answer this question.

![Figure 6.](http://jdh.adha.org/https://jdh.adha.org/content/jdenthyg/98/1/6/F6.medium.gif)

[Figure 6.](http://jdh.adha.org/content/98/1/6/F6)

Figure 6. 
PRISMA flowchart for Q6

The appropriate time for particles to settle down (i.e., fallow times) are relevant for dental AGPs, as suspended microorganisms (e.g., bacteria, fungi, viruses) may be found in the contaminated bioaerosol.98 This includes the use of 3-way air/water spray, dental cleaning with ultrasonic scaler and polishing, periodontal treatment with ultrasonic scaler, and dental preparation with high and low speed handpiece.99 Studies concerned with this topic have been conducted keeping the characteristics of the SARS-CoV-2 virus in consideration and are relevant during the COVID-19 pandemic. As such, most of the studies reviewed examined AGPs from ultrasonic scaling, some from high speed and low speed drilling, and a few from crown or root canal preparations, all of which were mainly conducted in enclosed spaces.62,68,69,99–101

Mathematical formulas of fallow times have been proposed in the literature and are commonly used in guidelines, although the appropriate level of contaminant removal efficiency threshold (90% vs 99%) has not yet reached a consensus.18 This mathematical formula has been provided by The National Institute for Occupational Safety and Health (NIOSH) to model the rate of decline in the concentration of an airborne contaminant.18 It is worth noting, however, that most of the studies reviewed did not provide calculations on how they determined fallow times.68,79,99,101–103 Few studies described using baseline aerosol concentrations to calculate the time it took to return to those levels.62,69,100

From the studies reviewed, it is complex to establish a set fallow time threshold without considering other critical factors. For example, fallow time is highly dependent on the air change per hour (ACH) in the dental clinic setting,62,102 that is, the higher the change per hour the lower the fallow time. When the ACH is unknown, guidance has been seen to vary from 15 to 180 minutes. Other authors suggest that a minimum of 10 minutes is sufficient when good ventilation (>10 ACH) is provided.79,102 Nevertheless, Shahdad et al. suggest that the longest fallow times occur when windows are closed and there is no mechanical ventilation.62 A more recent study conducted by Longo and colleagues suggested even shorter fallow time intervals. The authors stated that, to restore the baseline aerosol level values after the cessation of AGPs, less than 3 minutes of fallow time is enough when no additional ACH, and no fallow time is required with 20 additional ACH.104

The fallow time also depends on the dental equipment (e.g., air-turbine, high speed contra-angle handpiece), length of the dental procedure, the size of the aerosols generated, and other aerosol mitigation strategies, such as the use of rubber dams, high-volume evacuators (HVE) and extraoral suction devices.68,69,99–102 According to a review done by the College of General Dentistry in the United Knigdom (UK), fallow time is also critically impacted by the absence of HVE and poor ventilation (e.g., 1-2 ACH). Under those circumstances, the fallow period can increase up to 60 minutes.102

In addition, one of these studies assessed different clinical setting configuration (single room layout, semiprivate operatory with partial wall, and large multi-operator space), the use of HVE and fallow times.68 They concluded that dental aerosols were transient when HVE was employed regardless of the setting configuration, and as such the fallow times can be considered to be of 5 minutes under such conditions. Ultimately, it is important to be mindful that fallow time recommendations originated from the tuberculosis literature, and therefore might not be relevant when making recommendations in the context of respiratory viruses such as SARS-CoV-2.105

To summarize, ACH level and HVE use are relevant characteristics to factor when estimating fallow times after performing AGPs. As such, well-ventilated areas, with 10-15 ACHs,106 and/or the use of HVE can contribute to minimal fallow times (10 minutes or less) after dental AGPs, for example, ultrasonic scaling.

## DISCUSSION

With infections like COVID-19 and other communicable diseases that have the potential to spread through aerosols, AGPs will remain a viable risk of infection transmission for dental hygienists working in clinical settings. The purpose of this position paper is to provide dental hygienists and other oral health care providers with guidance when performing AGPs based on the latest scientific evidence. This includes identifying the risk of infection transmission associated with conducting AGPs; effectiveness of different types of preprocedural mouthrinses to reduce the microbial load of aerosols generated through AGPs; dental evacuation systems to reduce the transmission of aerosol far from its origin; appropriate PPE to provide optimal barrier to aerosols that may be contaminated; appropriate operatory setups for proper ventilation; and finally setting optimal fallow periods for aerosol to settle or leave the room. All of these aspects are reviewed to ultimately control the risk of infection transmission via aerosols following AGPs.

While there is a varying degree of robustness in the literature addressing the proposed questions, the following recommendations can be made based on the current evidence to help dental hygienists make informed decisions about their practices and to ensure their patients’ and own safety:

1.  There is not enough literature to suggest direct evidence of risk of transmission of SARS-CoV-2 between dental hygienists and patients despite AGPs being considered high risk procedures.

2.  The review suggests that CHX is effective in reducing bacterial contaminations in aerosols; however, there is limited understanding regarding which preprocedural mouthrinse is effective against SARS-CoV-2.

3.  The customized HVE tip with a suction cannula of 16 mm diameter at a high-flow rate offers the lowest splatter contamination.

4.  The combined use of protective eyewear, masks, and face shields are effective for the prevention of contamination of the facial and nasal region; however, there is no evidence to suggest their effectiveness against infection transmission.

5.  The appropriate combination of ventilation and filtration in dental operatories support the containment of aerosols.

6.  In terms of fallow time, a number of factors are accounted for when deciding on the appropriate resting time. When combining the use of HVE with a high ACH, minimal fallow time (10 minutes or less) seems to be enough for aerosols to settle.

The recommendations made by this position paper are based on the most recent scientific evidence rather than the precautionary approach adopted by many guidelines published over the last three years. Moreover, since it provides evidence on AGP related issues, it also serves as a guide for all other members of the oral health care team. A number of limitations should be considered when analyzing the results from this review. First, only studies published in English were included. Therefore, some evidence published in other languages might have been missing. Also, no quality appraisal was conducted for the included studies. As such, no comments on the quality of the evidence presented can be made, and dental hygienists are advised to contextualize the recommendations made to inform their practices. Finally, this review was conducted based on scientific literature and experimental studies, and did not include guidelines and grey literature, as they may be restricted in their approach reflecting only specific jurisdictional, organizational, or regulatory context.

Aerosol Generating Procedures are an integral part of oral healthcare settings, and it is a constant reality that aerosols appear to pose a risk of disease transmission between clinicians and their patients. Therefore, utilizing the best available scientific evidence, analyzing, and understanding the risk of infection transmission is important to support oral healthcare providers in making safe practice decisions. It is important to remember that recommendations made by this position paper are meant to complement, and not replace, already existing standard infection control protocols, vaccination requirements, and precautions such as pre-screening for illness to mitigate the risk of disease transmission in dental settings.

### Key Considerations

*   There is a lack of studies that indicate direct evidence of risk of transmission of SARS-CoV-2 among dental hygienists and their patients. However, even in the absence of evidence of direct SARS-CoV-2 transmission through AGPs in dental environment, the possibility still exists, until proved otherwise.

*   There is substantial evidence to suggest that the use of preprocedural mouthrinses reduce the level of bacterial contamination in aerosols generated by procedures commonly performed by dental hygienists. To a lesser extent, studies suggest that some mouthrinses have a virucidal effect but with very limited trial evidence after the use of AGPs.

*   Evidence suggests that the use of HVE either with or without an intraoral suction reduces aerosol contamination. Combining HVE with saliva ejectors, isolation adapters (i.e., with soft tissue retractors), or a rubber dam (when appropriate) may yield even higher aerosol reducing effectiveness.

*   The overall limited evidence suggests that the combined use of protective eyewear, masks (N-95, FFP2, or air-fed), and face shields are effective for the prevention of contamination of the facial and nasal region when performing AGPs.

*   The appropriate combination of engineering (ventilation and filtration) systems in conjunction with aerosol scavenging systems, can limit the spread of aerosols when performing AGPs.

*   With sufficient air ventilation, a fallow time of as low as 10 minutes or less can be enough for aerosols to completely settle in enclosed spaces. However, factors like the duration of the AGPs, the type of equipment used, and the presence of aerosol mitigating strategies and HVE can alter the time required.

## CONCLUSION

Aerosols produced during AGPs can pose a risk of infection transmission between dental hygienists and their patients. In the last three years, there has been an influx of evidence and guidelines about various aspects of AGPs. Therefore, it is important to integrate that knowledge to keep oral healthcare providers, including dental hygienists, updated on the current evidence regarding effective devices, methods, and protocols to mitigate the risk of infection transmission when performing AGPs.

## PRACTICE RELEVANCE

The evidence from this position paper will help inform dental hygienists and other oral care providers of the current evidence regarding effective devices, methods, and protocols to mitigate the risk of infection transmission when performing AGPs.

## ACKNOWLEDGMENTS

The authors would like to acknowledge the members of the steering committee, Lucas Guimarães Abreu, Khaled Altabtbaei, Kandis Garland, Kimi Khabra, Kyla Oshanek, Brian Partido, Elaine Powell, Helen Symons, Sylvie Martel, JoAnn Gurenlian, and Juliana Jackson, for their valuable contributions and insightful comments throughout the development of the paper.

## APPENDIX

View this table:
[Table I.](http://jdh.adha.org/content/98/1/6/T1)

Table I. 
Risk of transmission of microbial pathogens†

View this table:
[Table II.](http://jdh.adha.org/content/98/1/6/T2)

Table II. 
Preprocedural mouthrinse study characteristics†

View this table:
[Table III.](http://jdh.adha.org/content/98/1/6/T3)

Table III. 
Aerosol reduction study characteristics†

View this table:
[Table IV.](http://jdh.adha.org/content/98/1/6/T4)

Table IV. 
PPE study characteristics†

View this table:
[Table V.](http://jdh.adha.org/content/98/1/6/T5)

Table V. 
Operatory setup study characteristics†

View this table:
[Table VI.](http://jdh.adha.org/content/98/1/6/T6)

Table VI. 
Fallow time study characteristics†

## Footnotes

*   NDHRA priority area **Professional development: Occupational health** (determination and assessment of risks).

*   **DISCLOSURES**
    
    The authors have no conflicts of interest to declare.

*   Received May 4, 2023.
*   Accepted September 25, 2023.


*   Copyright © 2024 The American Dental Hygienists’ Association

This article is open access and may not be copied, distributed or modified without written permission from the American Dental Hygienists’ Association.

## REFERENCES

1.  1.Virdi MK, Durman K, Deacon S. The debate: What are aerosol-generating procedures in dentistry? A rapid review. JDR Clin Trans Res. 2021 Apr;6(2):115-127.
    
    

2.  2.Tellier R. Aerosol transmission of influenza A virus: a review of new studies. J R Soc Interface. 2009 Dec 6;6 Suppl 6(Suppl 6):S783-90.
    
    [CrossRef](http://jdh.adha.org/lookup/external-ref?access_num=10.1098/rsif.2009.0302.focus&link_type=DOI) 
    
    [PubMed](http://jdh.adha.org/lookup/external-ref?access_num=19773292&link_type=MED&atom=%2Fjdenthyg%2F98%2F1%2F6.atom) 

3.  3.Judson SD, Munster VJ. Nosocomial transmission of emerging viruses via aerosol-generating medical procedures. Viruses. 2019 Oct 12;11(10):940.
    
    [CrossRef](http://jdh.adha.org/lookup/external-ref?access_num=10.3390/v11100940&link_type=DOI) 
    
    [PubMed](http://jdh.adha.org/lookup/external-ref?access_num=http://www.n&link_type=MED&atom=%2Fjdenthyg%2F98%2F1%2F6.atom) 

4.  4.Comisi JC, Ravenel TD, Kelly A, et al. Aerosol and spatter mitigation in dentistry: Analysis of the effectiveness of 13 setups. J Esthet Restor Dent. 2021 Apr;33(3):466-479.
    
    

5.  5.Public Health Ontario. COVID-19 in dental care settings [Internet]. Ottawa: Ontario Agency for Health Protection and Promotion; 2022 [cited 2023 Nov 7]. Available from: [https://www.publichealthontario.ca/-/media/documents/ncov/ipac/2020/07/covid-19-dental-care-settings.pdf?la=en](https://www.publichealthontario.ca/-/media/documents/ncov/ipac/2020/07/covid-19-dental-care-settings.pdf?la=en)
    
    

6.  6.1.  Institute of Medicine (US) Forum on Microbial Threats; 
    2.  Knobler S, 
    3.  Mahmoud A, 
    4.  Lemon S, et al.
    
    Low DE. SARS: Lessons from Toronto. In: Institute of Medicine (US) Forum on Microbial Threats; Knobler S, Mahmoud A, Lemon S, et al., editors. Learning from SARS: Preparing for the Next Disease Outbreak: Workshop Summary. Washington (DC): National Academies Press (US); 2004.
    
    

7.  7.Centers for Disease Control and Prevention. CDC SARS response timeline [Internet]. Atlanta: Centers for Disease Control and Prevention; 2021 [cited 2022 Nov 7]. Available from: [https://archive.cdc.gov/#/details?url=](https://archive.cdc.gov/#/details?url=)[https://www.cdc.gov/about/history/sars/timeline.htm](https://www.cdc.gov/about/history/sars/timeline.htm)
    
    

8.  8.Harrel SK, Molinari J. Aerosols and splatter in dentistry: a brief review of the literature and infection control implications. J Am Dent Assoc. 2004 Apr;135(4):429-37.
    
    [Abstract/FREE Full Text](http://jdh.adha.org/lookup/ijlink/YTozOntzOjQ6InBhdGgiO3M6MTQ6Ii9sb29rdXAvaWpsaW5rIjtzOjU6InF1ZXJ5IjthOjQ6e3M6ODoibGlua1R5cGUiO3M6NDoiQUJTVCI7czoxMToiam91cm5hbENvZGUiO3M6NDoiamFkYSI7czo1OiJyZXNpZCI7czo5OiIxMzUvNC80MjkiO3M6NDoiYXRvbSI7czoyMToiL2pkZW50aHlnLzk4LzEvNi5hdG9tIjt9czo4OiJmcmFnbWVudCI7czowOiIiO30=) 

9.  9.Noordien N, Mulder-van Staden S, Mulder R. In Vivo Study of Aerosol, Droplets and Splatter Reduction in Dentistry. Viruses. 2021 Sep 25;13(10):1928.
    
    

10. 10.Rathore K, Rao D, Kumar P, Masih U. Evaluation of a specially-designed educational and interventional programme on institutionalized visually impaired children: A prospective interventional study. Spec Care Dentist. 2021 Nov;41(6):716-726.
    
    

11. 11.Innes N, Johnson IG, Al-Yaseen W, et al. A systematic review of droplet and aerosol generation in dentistry. J Dent. 2021 Feb;105:103556.
    
    [CrossRef](http://jdh.adha.org/lookup/external-ref?access_num=10.1016/j.jdent.2020.103556&link_type=DOI) 

12. 12.Meng L, Hua F, Bian Z. Coronavirus Disease 2019 (COVID-19): Emerging and Future Challenges for Dental and Oral Medicine. J Dent Res. 2020 May;99(5):481-487.
    
    [CrossRef](http://jdh.adha.org/lookup/external-ref?access_num=10.1177/0022034520914246&link_type=DOI) 
    
    [PubMed](http://jdh.adha.org/lookup/external-ref?access_num=http://www.n&link_type=MED&atom=%2Fjdenthyg%2F98%2F1%2F6.atom) 

13. 13.Barabari P, Moharamzadeh K. Novel coronavirus (COVID-19) and dentistry–A comprehensive review of literature. Dent J (Basel). 2020 May 21;8(2):53.
    
    

14. 14.Proffitt E. What will be the new normal for the dental industry? Br Dent J. 2020 May;228(9):678-680.
    
    [CrossRef](http://jdh.adha.org/lookup/external-ref?access_num=10.1038/s41415-020-1583-x&link_type=DOI) 

15. 15.World Health Organization. Infection prevention and control of epidemic- and pandemic-prone acute respiratory infections in health care [Internet]. Geneva: World Health Organization; 2014 [cited 2024 Jan 15]. Available from: [https://iris.who.int/handle/10665/112656](https://iris.who.int/handle/10665/112656)
    
    

16. 16.Micik RE, Miller RL, Mazzarella MA, Ryge G. Studies on dental aerobiology. I. Bacterial aerosols generated during dental procedures. J Dent Res. 1969 Jan-Feb;48(1):49-56.
    
    [CrossRef](http://jdh.adha.org/lookup/external-ref?access_num=10.1177/00220345690480012401&link_type=DOI) 
    
    [PubMed](http://jdh.adha.org/lookup/external-ref?access_num=4887699&link_type=MED&atom=%2Fjdenthyg%2F98%2F1%2F6.atom) 
    
    [Web of Science](http://jdh.adha.org/lookup/external-ref?access_num=A1969C697100008&link_type=ISI) 

17. 17.Siegel JD, Rhinehart E, Jackson M, et al. 2007 guideline for isolation precautions: Preventing transmission of infectious agents in health care settings. Am J Infect Control. 2007 Dec;35(10 Suppl 2):S65-164.
    
    [CrossRef](http://jdh.adha.org/lookup/external-ref?access_num=10.1016/j.ajic.2007.10.007&link_type=DOI) 
    
    [PubMed](http://jdh.adha.org/lookup/external-ref?access_num=18068815&link_type=MED&atom=%2Fjdenthyg%2F98%2F1%2F6.atom) 
    
    [Web of Science](http://jdh.adha.org/lookup/external-ref?access_num=000251803900001&link_type=ISI) 

18. 18.Singhal S, Farmer J, Aggarwal A, et al. A review of “Optimal Fallow Period” guidance across Canadian jurisdictions. Int Dent J. 2022 Feb;72(1):116-122.
    
    

19. 19.Liljeroos L, Huiskonen JT, Ora A, et al. Electron cryotomography of measles virus reveals how matrix protein coats the ribonucleocapsid within intact virions. Proc Natl Acad Sci U S A. 2011 Nov 1;108(44):18085-90.
    
    [Abstract/FREE Full Text](http://jdh.adha.org/lookup/ijlink/YTozOntzOjQ6InBhdGgiO3M6MTQ6Ii9sb29rdXAvaWpsaW5rIjtzOjU6InF1ZXJ5IjthOjQ6e3M6ODoibGlua1R5cGUiO3M6NDoiQUJTVCI7czoxMToiam91cm5hbENvZGUiO3M6NDoicG5hcyI7czo1OiJyZXNpZCI7czoxMjoiMTA4LzQ0LzE4MDg1IjtzOjQ6ImF0b20iO3M6MjE6Ii9qZGVudGh5Zy85OC8xLzYuYXRvbSI7fXM6ODoiZnJhZ21lbnQiO3M6MDoiIjt9) 

20. 20.Rossman JS, Lamb RA. Influenza virus assembly and budding. Virology. 2011 Mar 15;411(2):229-36.
    
    [CrossRef](http://jdh.adha.org/lookup/external-ref?access_num=10.1016/j.virol.2010.12.003&link_type=DOI) 
    
    [PubMed](http://jdh.adha.org/lookup/external-ref?access_num=21237476&link_type=MED&atom=%2Fjdenthyg%2F98%2F1%2F6.atom) 
    
    [Web of Science](http://jdh.adha.org/lookup/external-ref?access_num=000288343000008&link_type=ISI) 

21. 21.Rafiee A, Carvalho R, Lunardon D, et al. Particle size, mass concentration, and microbiota in dental aerosols. J Dent Res. 2022 Jul;101(7):785-792
    
    

22. 22.Dhand R, Li J. Coughs and sneezes: Their role in transmission of respiratory viral infections, including SARS-CoV-2. Am J Respir Crit Care Med. 2020 Sep 1;202(5):651-659.
    
    [CrossRef](http://jdh.adha.org/lookup/external-ref?access_num=10.1164/rccm.202004-1263PP&link_type=DOI) 
    
    [PubMed](http://jdh.adha.org/lookup/external-ref?access_num=32543913&link_type=MED&atom=%2Fjdenthyg%2F98%2F1%2F6.atom) 

23. 23.Covidence. Better systematic review management [Internet]. Melbourne: Covidence; 2022 [cited 2022 Aug 6]. Available from: [https://www.covidence.org/](https://www.covidence.org/)
    
    

24. 24.Levit M, Levit L. Infection risk of COVID-19 in dentistry remains unknown: A preliminary systematic review. Infect Dis Clin Pract (Baltim Md). 2021 Mar;29(2):e70-e77.
    
    

25. 25.Amiri A, Qi F, Carrazzone Cal Alonso MB, et al. Evaluation of the droplets and aerosols, posing potential risks of COVID-19 disease infection transmission in dentistry: A systematic review and meta-analysis of observational studies. Pesqui Bras Em Odontopediatria E Clínica Integrada. SciELO Brasil; 2021;21.
    
    

26. 26.Al-Moraissi EA, Kaur A, Günther F, et al. Can aerosols-generating dental, oral and maxillofacial, and orthopedic surgical procedures lead to disease transmission? An implication on the current COVID-19 pandemic. Front Oral Health. 2022 Aug 1;3:974644.
    
    

27. 27.Manzar S, Kazmi F, Shahzad HB, et al. Estimation of the risk of COVID-19 transmission through aerosol-generating procedures. Dent Med Probl. 2022 Jul-Sep;59(3):351-356.
    
    

28. 28.Mirbod P, Haffner EA, Bagheri M, Higham JE. Aerosol formation due to a dental procedure: Insights leading to the transmission of diseases to the environment. J R Soc Interface. 2021 Mar;18(176):20200967.
    
    

29. 29.Tanaka H, Kurita H, Shibuya Y, et al. COVID-19 transmission in dental and oral/maxillofacial surgical practice during pandemic: Questionnaire survey in 51 university hospitals in Japan. J Hosp Infect. 2022 Jul;125:21-27.
    
    

30. 30.Baldion PA, Rodríguez HO, Guerrero CA, et al. Infection risk prediction model for COVID-19 based on an analysis of the settlement of particles generated during dental procedures in dental clinics. Int J Dent. 2021 Dec 30;2021:7832672.
    
    

31. 31.Vasan PK, Shinde O, Banga KS, et al. COVID-19 contraction among dental healthcare workers in the department of conservative dentistry and endodontics–A retrospective analysis during the pandemic. Risk Manag Healthc Policy. 2022 Jun 22;15:1243-1252.
    
    

32. 32.Nagraj SK, Eachempati P, Paisi M, et al. Preprocedural mouth rinses for preventing transmission of infectious diseases through aerosols in dental healthcare providers. Cochrane Database Syst Rev. 2022 Aug 22;8(8):CD013826.
    
    

33. 33.Marui VC, Souto MLS, Rovai ES, et al. Efficacy of preprocedural mouthrinses in the reduction of microorganisms in aerosol: A systematic review. J Am Dent Assoc. 2019 Dec;150(12):1015-1026.e1.
    
    [CrossRef](http://jdh.adha.org/lookup/external-ref?access_num=10.1016/j.adaj.2019.06.024&link_type=DOI) 

34. 34.Mohd-Said S, Mohd-Dom TN, Suhaimi N, et al. Effectiveness of pre-procedural mouth rinses in reducing aerosol contamination during periodontal prophylaxis: A systematic review. Front Med (Lausanne). 2021 Jun 10;8:600769.
    
    

35. 35.Anjum A, Hosein M, Butt SA, et al. Efficacy of two mouth rinses in reducing aerosol bacterial load during ultrasonic scaling. J Adv Med Med Res. 2019;31(7):1–9.
    
    

36. 36.Burgos-Ramos E, Urbieta IR, Rodríguez D. Is hydrogen peroxide an effective mouthwash for reducing the viral load of SARS-CoV-2 in dental clinics? Saudi Dent J. 2022 Mar;34(3):237-242.
    
    

37. 37.Choi JO, Choi YJ, Nam SH. Study on the prevention of cross-infection by aerosols during scaling. Biomed Res. 2018;29(18):3479–82.
    
    

38. 38.Das SJ, Kharbuli D, Alam ST. Effects of preprocedural mouth rinse on microbial load in aerosols produced during the ultrasonic scaling: A randomized controlled trial. J Indian Soc Periodontol. 2022 Sep-Oct;26(5):478-484.
    
    

39. 39.Gund MP, Naim J, Hannig M, et al. CHX and a face shield cannot prevent contamination of surgical masks. Front Med (Lausanne). 2022 May 23;9:896308.
    
    

40. 40.Ramya V, Valiathan M, Hussain S. To determine the efficacy of 0.12% Chlorhexidine mouthrinses in reducing viable bacterial count in dental aerosols when used as a preprocedural rinse during the pandemic era - A prospective clinical pilot study. Asian J Adv Med Sci. 2022 Apr;4(1):17–24.
    
    

41. 41.Rao RM, Shenoy N, Shetty V. Determination of efficacy of pre-procedural mouth rinsing in reducing aerosol contamination produced by ultrasonic scalers. J Health Allied Sci. 2015;5(03):52–56.
    
    

42. 42.Sadun A, Taiyeb-Ali T, Fathilah A, et al. Effectiveness of pre-procedural rinsing with essential oils-based mouthrinse to reduce aerosol contamination of periodontitis patients. Sains Malays. 2020;49(1):139–143.
    
    

43. 43.Takenaka S, Sotozono M, Yashiro A, et al. Efficacy of combining an extraoral high-volume evacuator with preprocedural mouth rinsing in reducing aerosol contamination produced by ultrasonic scaling. Int J Environ Res Public Health. 2022 May 16;19(10):6048.
    
    

44. 44.Varghese CM, Sheokand V, Bhardwaj A, et al. Self prepared herbal mouthwash used as pre-procedural rinse in reducing dental aerosol: A substitute to chemical mouthrinse: A clinico-microbiological study. Int J Ayurvedic Med. 2021 Sept;12(3):593–598.
    
    

45. 45.Warad S, Bhatagunaki RV. Effect of different mouth washes as a pre-procedural rinse to combat aerosol contamination–A cross-sectional study. Univ J Dent Sci. 2020;6(3):58–62.
    
    

46. 46.Yadav S, Kumar S, Srivastava P, et al. Comparison of efficacy of three different mouthwashes in reducing aerosol contamination produced by ultrasonic scaler: A pilot study. Indian J Dent Sci. 2018;10(1):6.
    
    

47. 47.Prakash S, Shelke AU. Role of Triphala in dentistry. J Indian Soc Periodontol. 2014 Mar;18(2):132-5.
    
    

48. 48.Ebrahimi T, Shamshiri AR, Alebouyeh M, Mohebbi SZ. Effectiveness of mouthwashes on reducing SARS-CoV-2 viral load in oral cavity: a systematic review and meta-analysis. BMC Oral Health. 2023 Jul 3;23(1):443.
    
    

49. 49.Silva A, Azevedo M, Sampaio-Maia B, Sousa-Pinto B. The effect of mouthrinses on severe acute respiratory syndrome coronavirus 2 viral load: A systematic review. J Am Dent Assoc. 2022 Jul;153(7):635-648.e16.
    
    

50. 50.Ortega KL, Rech BO, El Haje GLC, et al. Do hydrogen peroxide mouthwashes have a virucidal effect? A systematic review. J Hosp Infect. 2020 Dec;106(4):657-662.
    
    

51. 51.Allison JR, Dowson C, Pickering K, et al. Local exhaust ventilation to control dental aerosols and droplets. J Dent Res. 2022 Apr;101(4):384-391.
    
    

52. 52.Lertsooksawat W, Horsophonphong S, Chestsuttayangkul Y. A novel negative airflow aerosol chamber minimized aerosol transmission during ultrasonic scaling: A laboratory investigation. M Dent J. 2022 Mar;42(1):47–54.
    
    

53. 53.Gheorghita D, Kun Szabó F, Ajtai T, et al. Aerosol reduction of 2 dental extraoral scavenger devices in vitro. Int Dent J. 2022 Oct;72(5):691-697.
    
    

54. 54.Blackley BH, Anderson KR, Panagakos F, et al. Efficacy of dental evacuation systems for aerosol exposure mitigation in dental clinic settings. J Occup Environ Hyg. 2022 May;19(5):281-294.
    
    

55. 55.Graetz C, Hülsbeck V, Düffert P, et al. Influence of flow rate and different size of suction cannulas on splatter contamination in dentistry: Results of an exploratory study with a high-volume evacuation system. Clin Oral Investig. 2022 Sep;26(9):5687-5696
    
    

56. 56.Choi JJE, Chen J, Choi YJ, et al. Dental high-speed handpiece and ultrasonic scaler aerosol generation levels and the effect of suction and air supply. Infect Control Hosp Epidemiol. 2023 Jun;44(6):926-933.
    
    

57. 57.Graetz C, Düffert P, Heidenreich R, et al. The efficacy of an extraoral scavenging device on reducing aerosol particles ≤ 5 μm during dental aerosol-generating procedures: An exploratory pilot study in a university setting. BDJ Open. 2021 May 20;7(1):19.
    
    

58. 58.Matys J, Grzech-Leśniak K. Dental aerosol as a hazard risk for dental workers. Materials (Basel). 2020 Nov 12;13(22):5109.
    
    

59. 59.He Z, Gao Q, Henley A, et al. Efficacy of aerosol reduction measures for dental aerosol generating procedures. Aerosol Sci Technol. 2022 May 4;56(5):413–424.
    
    

60. 60.Lertsooksawat W. Efficacy of extraoral suction devices in aerosol and splatter reduction during ultrasonic scaling: A laboratory investigation. J Dent Res Dent Clin Dent Prospects. 2021 Summer;15(3):197-202.
    
    

61. 61.Dahlke WO, Cottam MR, Herring MC, et al. Evaluation of the spatter-reduction effectiveness of two dry-field isolation techniques. J Am Dent Assoc. 2012 Nov;143(11):1199-204
    
    [Abstract/FREE Full Text](http://jdh.adha.org/lookup/ijlink/YTozOntzOjQ6InBhdGgiO3M6MTQ6Ii9sb29rdXAvaWpsaW5rIjtzOjU6InF1ZXJ5IjthOjQ6e3M6ODoibGlua1R5cGUiO3M6NDoiQUJTVCI7czoxMToiam91cm5hbENvZGUiO3M6NDoiamFkYSI7czo1OiJyZXNpZCI7czoxMToiMTQzLzExLzExOTkiO3M6NDoiYXRvbSI7czoyMToiL2pkZW50aHlnLzk4LzEvNi5hdG9tIjt9czo4OiJmcmFnbWVudCI7czowOiIiO30=) 

62. 62.Shahdad S, Hindocha A, Patel T, et al. Fallow time determination in dentistry using aerosol measurement in mechanically and non-mechanically ventilated environments. Br Dent J [Internet]. 2021 Aug 24 [cited 2023 Jan 6]; Available from: [https://www.nature.com/articles/s41415-021-3369-1](https://www.nature.com/articles/s41415-021-3369-1)
    
    

63. 63.Piela K, Watson P, Donnelly R, et al. Aerosol reduction efficacy of different intra-oral suction devices during ultrasonic scaling and high-speed handpiece use. BMC Oral Health. 2022 Sep 6;22(1):388.
    
    

64. 64.D’Antonio N, Newnum J, Kanellis M, et al. Assessment of respirable aerosol concentrations using local ventilation controls in an open multi-chair dental clinic. J Occup Environ Hyg. 2022 May;19(5):246-255
    
    

65. 65.Choudhary S, Bach T, Wallace MA, et al. Assessment of infectious diseases risks from dental aerosols in real-world settings. Open Forum Infect Dis. 2022 Nov 11;9(11):ofac617.
    
    

66. 66.Suprono MS, Won J, Savignano R, et al. A clinical investigation of dental evacuation systems in reducing aerosols. J Am Dent Assoc. 2021 Jun;152(6):455-462
    
    

67. 67.Rexhepi I, Mangifesta R, Santilli M, et al. Effects of natural ventilation and saliva standard ejectors during the COVID-19 pandemic: A quantitative analysis of aerosol produced during dental procedures. Int J Environ Res Public Health. 2021 Jul 13;18(14):7472.
    
    

68. 68.Choudhary S, Durkin MJ, Stoeckel DC, et al. Comparison of aerosol mitigation strategies and aerosol persistence in dental environments. Infect Control Hosp Epidemiol. 2022 Dec;43(12):1779–1784.
    
    

69. 69.Ehtezazi T, Evans DG, Jenkinson ID, et al. SARS-CoV-2: characterisation and mitigation of risks associated with aerosol generating procedures in dental practices. Br Dent J. 2021 Jan 7:1–7.
    
    

70. 70.Nulty A, Lefkaditis C, Zachrisson P, et al. A clinical study measuring dental aerosols with and without a high-volume extraction device. Br Dent J. 2020 Nov 20:1–8.
    
    

71. 71.Chavis SE, Hines SE, Dyalram D, et al. Can extraoral suction units minimize droplet spatter during a simulated dental procedure? J Am Dent Assoc. 2021 Feb;152(2):157–65.
    
    

72. 72.Shahdad S, Patel T, Hindocha A, et al. The efficacy of an extraoral scavenging device on reduction of splatter contamination during dental aerosol generating procedures: An exploratory study. Br Dent J. 2020 Sep 11:1–10.
    
    

73. 73.Senpuku H, Fukumoto M, Uchiyama T, et al. Effects of extraoral suction on droplets and aerosols for infection control practices. Dent J (Basel). 2021 Jul 7;9(7):80.
    
    

74. 74.Chestsuttayangkul Y, Lertsooksawat W, Horsophonphong S. Efficacy of dental barriers in aerosols and splatters reduction during an ultrasonic scaling: An in-vitro study. J Int Soc Prev Community Dent. 2022 Jan 29;12(1):71-78.
    
    

75. 75.Montalli VAM, Garcez AS, Montalli GAM, et al. Individual biosafety barrier in dentistry: An alternative in times of covid-19. Preliminary study. Rev Gaúch Odontol. 2020;68:e20200018.
    
    

76. 76.Yang M, Chaghtai A, Melendez M, et al. Mitigating saliva aerosol contamination in a dental school clinic. BMC Oral Health. 2021 Feb 5;21(1):52.
    
    

77. 77.Interventions to reduce contaminated aerosols produced during dental procedures for preventing infectious diseases. Cochrane Database Syst Rev. 2020 Oct 12;10(10):CD013686.
    
    

78. 78.Samaranayake LP, Fakhruddin KS, Buranawat B, Panduwawala C. The efficacy of bio-aerosol reducing procedures used in dentistry: a systematic review. Acta Odontol Scand. 2021 Jan;79(1):69-80.
    
    

79. 79.Robertson C, Clarkson JE, Aceves-Martins M, et al. A review of aerosol generation mitigation in international dental guidance. Int Dent J. 2022 Apr;72(2):203-210.
    
    

80. 80.Deana NF, Seiffert A, Aravena-Rivas Y, et al. Recommendations for safe dental care: A systematic review of clinical practice guidelines in the first year of the COVID-19 pandemic. Int J Environ Res Public Health. 2021 Sep 24;18(19):10059
    
    

81. 81.Afzha R, Chatterjee A, Subbaiah SK, Pradeep AR. Microbial contamination of contact lenses after scaling and root planing using ultrasonic scalers with and without protective eyewear: A clinical and microbiological study. J Indian Soc Periodontol. 2016 May-Jun;20(3):273-8.
    
    

82. 82.Bridgman JB, Newsom AL, Chrisp DJ, et al. Comparison of an Air-Fed mask system with hospital-issued personal protection equipments for dental aerosol protection during the COVID-19 pandemic. Open Dent J. 2021 Dec 31;15(1).
    
    

83. 83.Checchi V, Montevecchi M, Checchi L. Variation of efficacy of filtering face pieces respirators over time in a dental setting: A pilot study. Dent J (Basel). 2021 Mar 24;9(4):36.
    
    

84. 84.Ionescu AC, Brambilla E, Manzoli L, et al. Efficacy of personal protective equipment against coronavirus transmission via dental handpieces. J Am Dent Assoc. 2021 Aug;152(8):631-640..
    
    

85. 85.Santa Rita de Assis J, Garcez AS, Suzuki H, Montalli VAM, et al. Assessment of a biosafety device to control contamination by airborne transmission during orthodontic/dental procedures. Int J Dent. 2022 Apr 15;2022:8302826.
    
    

86. 86.Teichert-Filho R, Baldasso C, Campos MM, Gomes M. Protective device to reduce aerosol dispersion in dental clinics during the COVID-19 pandemic. Int Endod J. 2020 Nov;53(11):1588-1597.
    
    

87. 87.Villa A, Grenon M. The Cupola: an additional layer of protection for providers working in the oropharyngeal region. BMC Res Notes. 2021 Mar 25;14(1):115.
    
    

88. 88.Long Y, Hu T, Liu L, et al. Effectiveness of N95 respirators versus surgical masks against influenza: A systematic review and meta-analysis. J Evid Based Med. 2020 May;13(2):93-101.
    
    [PubMed](http://jdh.adha.org/lookup/external-ref?access_num=http://www.n&link_type=MED&atom=%2Fjdenthyg%2F98%2F1%2F6.atom) 

89. 89.Jefferson T, Foxlee R, Del Mar C, et al. Physical interventions to interrupt or reduce the spread of respiratory viruses: Systematic review. BMJ. 2008 Jan 12;336(7635):77-80.
    
    [Abstract/FREE Full Text](http://jdh.adha.org/lookup/ijlink/YTozOntzOjQ6InBhdGgiO3M6MTQ6Ii9sb29rdXAvaWpsaW5rIjtzOjU6InF1ZXJ5IjthOjQ6e3M6ODoibGlua1R5cGUiO3M6NDoiQUJTVCI7czoxMToiam91cm5hbENvZGUiO3M6MzoiYm1qIjtzOjU6InJlc2lkIjtzOjExOiIzMzYvNzYzNS83NyI7czo0OiJhdG9tIjtzOjIxOiIvamRlbnRoeWcvOTgvMS82LmF0b20iO31zOjg6ImZyYWdtZW50IjtzOjA6IiI7fQ==) 

90. 90.Collins AP, Service BC, Gupta S, et al. N95 respirator and surgical mask effectiveness against respiratory viral illnesses in the healthcare setting: A systematic review and meta-analysis. J Am Coll Emerg Physicians Open. 2021 Oct 28;2(5):e12582.
    
    

91. 91.Holliday R, Allison JR, Currie CC, et al. Evaluating contaminated dental aerosol and splatter in an open plan clinic environment: Implications for the COVID-19 pandemic. J Dent. 2021 Feb;105:103565.
    
    

92. 92.Ren YF, Huang Q, Marzouk T, et al. Effects of mechanical ventilation and portable air cleaner on aerosol removal from dental treatment rooms. J Dent. 2021 Feb;105:103576.
    
    

93. 93.Zhu M, Medina M, Nalliah R, et al. Experimental evaluation of aerosol mitigation strategies in large open-plan dental clinics. J Am Dent Assoc. 2022 Mar;153(3):208-220.
    
    

94. 94.Dabiri D, Conti SR, Sadoughi Pour N, et al. A multi-disciplinary review on the aerobiology of COVID-19 in dental settings. Front Dent Med. 2021;2:726395.
    
    

95. 95.Kumar PS, Geisinger ML, Avila-Ortiz G. Methods to mitigate infection spread from aerosol-generating dental procedures. J Periodontol. 2021 Jun;92(6):784-792.
    
    

96. 96.Isha SN, Ahmad A, Kabir R, Apu EH. Dental clinic architecture prevents COVID-19-like infectious diseases. HERD. 2020 Oct;13(4):240-241.
    
    

97. 97.Rathi N, Deulkar PV, Mehta J, et al. Air management techniques in dental office in post COVID era: A literature review. Braz Dent Sci. 2022 Jan-Mar;25(1).
    
    

98. 98.Zemouri C, de Soet H, Crielaard W, Laheij A. A scoping review on bio-aerosols in healthcare and the dental environment. PLoS One. 2017 May 22;12(5):e0178007.
    
    [CrossRef](http://jdh.adha.org/lookup/external-ref?access_num=10.1371/journal.pone.0178007&link_type=DOI) 
    
    [PubMed](http://jdh.adha.org/lookup/external-ref?access_num=http://www.n&link_type=MED&atom=%2Fjdenthyg%2F98%2F1%2F6.atom) 

99. 99.Fennelly M, Gallagher C, Harding M, et al. Real-time monitoring of aerosol generating dental procedures. J Dent. 2022 May;120:104092.
    
    

100.100.Li X, Mak CM, Ma KW, Wong HM. Restoration of dental services after COVID-19: The fallow time determination with laser light scattering. Sustain Cities Soc. 2021 Nov;74:103134.
    
    

101.101.Vernon JJ, Black EV, Dennis T, et al. Dental mitigation strategies to reduce aerosolization of SARS-CoV-2. J Dent Res. 2021 Dec;100(13):1461-1467.
    
    

102.102.Faculty of General Dental Practice. Implications of COVID-19 for the safe management of general dental practice: A practical guide [Internet]. London: College of General Dentistry; 2020 [cited 2023 Nov 7]. Available from: [https://cgdent.uk/wp-content/uploads/2020/10/FGDP-CGDent-Implications-of-COVID-19-for-the-safe-management-of-general-dental-practice-2-October-2020-v2.pdf](https://cgdent.uk/wp-content/uploads/2020/10/FGDP-CGDent-Implications-of-COVID-19-for-the-safe-management-of-general-dental-practice-2-October-2020-v2.pdf)
    
    

103.103.Clarkson J, Ramsay C, Richards D, et al. Aerosol generating procedures and their mitigation in international dental guidance documents - A rapid review. Cochrane Oral Health. 2020;72:1–69.
    
    

104.104.Longo AB, Rier E, Colleen Porter R, et al. Factors modulating fallow period of aerosol-generating dental procedures in a clinical setting. J Can Dent Assoc. 2023 May;89:n5.
    
    

105.105.Ontario Public Health. IPAC recommendations for use of personal protective equipment for care of individuals with suspect or confirmed COVID-19 [Internet]. Ottawa: Public Health Ontario; 2021 [cited 2023 Nov 7]. Available from: [https://www.publichealthontario.ca/-/media/documents/ncov/updated-ipac-measures-covid-19.pdf?la=en#:~:text=The%20recommended%20PPE%20when%20providing,protection%2C%20gown%2C%20and%20gloves](https://www.publichealthontario.ca/-/media/documents/ncov/updated-ipac-measures-covid-19.pdf?la=en#:~:text=The%20recommended%20PPE%20when%20providing,protection%2C%20gown%2C%20and%20gloves).
    
    

106.106.Centers for Disease Control and Prevention. Infection control guidelines: Appendix B Air [Internet]. Atlanta: Centers for Disease Control and Prevention; 2019 [cited 2023 Aug 15]. Available from: [https://www.cdc.gov/infectioncontrol/guidelines/environmental/appendix/air.html](https://www.cdc.gov/infectioncontrol/guidelines/environmental/appendix/air.html)
    
    

107.107.Barros MC, Pedrinha VF, Velásquez-Espedilla EG, et al. Aerosols generated by high-speed handpiece and ultrasonic unit during endodontic coronal access alluding to the COVID-19 pandemic. Sci Rep. 2022 Mar 21;12(1):4783.
    
    

108.108.Narayana T, Mohanty L, Sreenath G, Vidhyadhari P. Role of preprocedural rinse and high volume evacuator in reducing bacterial contamination in bioaerosols. J Oral Maxillofac Pathol. 2016 Jan-Apr;20(1):59-65.