Interventions to reduce contaminated aerosols produced during dental procedures for preventing infectious diseases

Workplace interventions to reduce the risk of SARS-CoV-2 infection outside of healthcare settings

BACKGROUND

Although many people infected with SARS-CoV-2 (severe acute respiratory syndrome coronavirus 2) experience no or mild symptoms, some individuals can develop severe illness and may die, particularly older people and those with underlying medical problems. Providing evidence-based interventions to prevent SARS-CoV-2 infection has become more urgent with the potential psychological toll imposed by the coronavirus disease 2019 (COVID-19) pandemic. Controlling exposures to occupational hazards is the fundamental method of protecting workers. When it comes to the transmission of viruses, workplaces should first consider control measures that can potentially have the most significant impact. According to the hierarchy of controls, one should first consider elimination (and substitution), then engineering controls, administrative controls, and lastly, personal protective equipment. This is the first update of a Cochrane review published 6 May 2022, with one new study added.

OBJECTIVES

To assess the benefits and harms of interventions in non-healthcare-related workplaces aimed at reducing the risk of SARS-CoV-2 infection compared to other interventions or no intervention.

SEARCH METHODS

We searched the Cochrane Central Register of Controlled Trials (CENTRAL), MEDLINE, Embase, Web of Science Core Collections, Cochrane COVID-19 Study Register, World Health Organization (WHO) COVID-19 Global literature on coronavirus disease, ClinicalTrials.gov, the WHO International Clinical Trials Registry Platform, and medRxiv to 13 April 2023.

SELECTION CRITERIA

We included randomised controlled trials (RCTs) and non-randomised studies of interventions. We included adult workers, both those who come into close contact with clients or customers (e.g. public-facing employees, such as cashiers or taxi drivers), and those who do not, but who could be infected by coworkers. We excluded studies involving healthcare workers. We included any intervention to prevent or reduce workers' exposure to SARS-CoV-2 in the workplace, defining categories of intervention according to the hierarchy of hazard controls (i.e. elimination; engineering controls; administrative controls; personal protective equipment).

DATA COLLECTION AND ANALYSIS

We used standard Cochrane methods. Our primary outcomes were incidence rate of SARS-CoV-2 infection (or other respiratory viruses), SARS-CoV-2-related mortality, adverse events, and absenteeism from work. Our secondary outcomes were all-cause mortality, quality of life, hospitalisation, and uptake, acceptability, or adherence to strategies. We used the Cochrane RoB 2 tool to assess risk of bias, and GRADE methods to evaluate the certainty of evidence for each outcome.

MAIN RESULTS

We identified 2 studies including a total of 16,014 participants. Elimination-of-exposure interventions We included one study examining an intervention that focused on elimination of hazards, which was an open-label, cluster-randomised, non-inferiority trial, conducted in England in 2021. The study compared standard 10-day self-isolation after contact with an infected person to a new strategy of daily rapid antigen testing and staying at work if the test is negative (test-based attendance). The trialists hypothesised that this would lead to a similar rate of infections, but lower COVID-related absence. Staff (N = 11,798) working at 76 schools were assigned to standard isolation, and staff (N = 12,229) working at 86 schools were assigned to the test-based attendance strategy. The results between test-based attendance and standard 10-day self-isolation were inconclusive for the rate of symptomatic polymerase chain reaction (PCR)-positive SARS-CoV-2 infection (rate ratio (RR) 1.28, 95% confidence interval (CI) 0.74 to 2.21; 1 study; very low-certainty evidence). The results between test-based attendance and standard 10-day self-isolation were inconclusive for the rate of any PCR-positive SARS-CoV-2 infection (RR 1.35, 95% CI 0.82 to 2.21; 1 study; very low-certainty evidence). COVID-related absenteeism rates were 3704 absence days in 566,502 days-at-risk (6.5 per 1000 working days) in the control group and 2932 per 539,805 days-at-risk (5.4 per 1000 working days) in the intervention group (RR 0.83, 95% CI 0.55 to 1.25). We downgraded the certainty of the evidence to low due to imprecision. Uptake of the intervention was 71% in the intervention group, but not reported for the control intervention. The trial did not measure our other outcomes of SARS-CoV-2-related mortality, adverse events, all-cause mortality, quality of life, or hospitalisation. We found seven ongoing studies using elimination-of-hazard strategies, six RCTs and one non-randomised trial. Administrative control interventions We found one ongoing RCT that aims to evaluate the efficacy of the Bacillus Calmette-Guérin (BCG) vaccine in preventing COVID-19 infection and reducing disease severity. Combinations of eligible interventions We included one non-randomised study examining a combination of elimination of hazards, administrative controls, and personal protective equipment. The study was conducted in two large retail companies in Italy in 2020. The study compared a safety operating protocol, measurement of body temperature and oxygen saturation upon entry, and a SARS-CoV-2 test strategy with a minimum activity protocol. Both groups received protective equipment. All employees working at the companies during the study period were included: 1987 in the intervention company and 1798 in the control company. The study did not report an outcome of interest for this systematic review. Other intervention categories We did not find any studies in this category.

AUTHORS' CONCLUSIONS

We are uncertain whether a test-based attendance policy affects rates of PCR-positive SARS-CoV-2 infection (any infection; symptomatic infection) compared to standard 10-day self-isolation amongst school and college staff. A test-based attendance policy may result in little to no difference in absenteeism rates compared to standard 10-day self-isolation. The non-randomised study included in our updated search did not report any outcome of interest for this Cochrane review. As a large part of the population is exposed in the case of a pandemic, an apparently small relative effect that would not be worthwhile from the individual perspective may still affect many people, and thus become an important absolute effect from the enterprise or societal perspective. The included RCT did not report on any of our other primary outcomes (i.e. SARS-CoV-2-related mortality and adverse events). We identified no completed studies on any other interventions specified in this review; however, eight eligible studies are ongoing. More controlled studies are needed on testing and isolation strategies, and working from home, as these have important implications for work organisations.

Dental aerosol-producing treatments: Comparison of contamination patterns of face shields and surgical masks

During the COVID-19 pandemic, dental face shields were recommended to protect the eyes. This study aimed to examine to what extent face shield and mask contamination differ when a pre-procedural mouth rinsing with Chlorhexidine (CHX) is conducted before treatment. In this prospective, randomized study, three groups of subjects were formed (rinsing with 0.1% CHX, water, or no rinsing (control) before aerosol-producing treatments). After each of the 301 treatments, the practitioner's face shield was swabbed with eSwab and the mask was brought into contact with agar plates. Sampling was done from the exterior surface only. Samples were cultured for 48 h at 35 °C under aerobic and anaerobic conditions. Bacteria were classified by phenotypic characteristics, biochemical test methods, and matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS). Colony-forming units were counted and mean values were compared (WSR, H-test, U-test, p < 0.05). Within each subject group, face shields showed significantly more contamination than surgical masks (control group: 350 CFU, 50 CFU; intervention water: 270 CFU, 40 CFU; intervention CHX: 250 CFU, 30 CFU). Comparison of face shields of the different subject groups did not reveal any statistically significant differences. However, CHX resulted in a statistically significant bacterial reduction on surgical masks compared to the water and control group (control: 50 CFU, intervention water: 40 CFU, intervention CHX: 30 CFU). Contamination of face shields and surgical masks was highest in the control group, followed by the water group, and lowest in the intervention group with CHX. Streptococcus spp. and Staphylococcus spp. dominated, representing the oral and cutaneous flora. Contamination of masks worn with or without face shields did not differ. Presumably, face shields intercept first splashes and droplets, while the masks were mainly exposed to bioaerosol mist. Consequently, face shields protect the facial region and surroundings from splashes and droplets, but not the mask itself. A pre-procedural mouth rinse with CHX had no statistically significant reducing effect on contamination of the face shield, but a statistically significant reducing effect was observed on contamination of the mask.

Aerosol-generating procedures and associated control/mitigation measures: Position paper from the Canadian Dental Hygienists Association and the American Dental Hygienists' Association

Background

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

Methods

The authors searched 6 databases-MEDLINE, EMBASE, Scopus, Web of Science, Cochrane Library, and Google Scholar-for relevant scientific evidence published between January 2012 and December 2022 to answer 6 research questions about the 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. The literature on the risk of infection transmission including SARS-CoV-2 between dental hygienists and their patients is limited. Although several mouthrinses are effective in reducing bacterial contaminations in aerosols, their effectiveness against SARS-CoV-2 is also limited. The combined use of eyewear, masks, and face shields is effective in preventing 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 is effective in limiting the spread of aerosols.

Discussion and Conclusion

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

Study of aerosol dispersion and control in dental practice

OBJECTIVES

In this study, we investigated the dispersion patterns of aerosols and droplets in dental clinics and developed a suction device to evaluate its effectiveness in reducing aerosols during dental procedures.

MATERIALS AND METHODS

Firstly, the continuous images of oral aerosols and droplets were photographed with a high-speed camera, and the trajectories of these particles were recognized and processed by Image J to determine key parameters affecting particle dispersion: diffusion velocity, distance, and angle. Secondly, based on the parameter data, the flow field of aerosol particles around the oral cavity was simulated using computational fluid dynamics (CFD), and the flow field under adsorption conditions was simulated to demonstrate the aerodynamic characteristics and capture efficiencies of the single-channel and three-channel adsorption ports at different pressures. Finally, according to the simulated data, a three-channel suction device was developed, and the capture efficiency of the device was tested by the fluorescein tracer method.

RESULTS

The dispersion experimental data showed that aerosol particles' maximum diffusion velocity, distance, and angle were 6.2 m/s, 0.55 m, and 130°, respectively. The simulated aerosol flow-field distribution was consistent with the aerosol dispersion patterns. The adsorption simulation results showed that the outlet flow rate of single-channel adsorption was 184.5 L/s at - 350 Pa, and the aerosol capture efficiency could reach 79.4%. At - 350 Pa and - 150 Pa, the outlet flow rate of three-channel adsorption was 228.9 L/s, and the capture efficiency was 99.23%. The adsorption experimental data showed that the capture efficiency of three-channel suction device was 97.71%.

CONCLUSIONS

A three-channel suction device was designed by simulations and experiments, which can capture most aerosols in the dental clinic and prevent them from spreading.

CLINICAL RELEVANCE

Using three-channel suction devices during oral treatment effectively reduces the spread of oral aerosols, which is essential to prevent the spread of epidemics and ensure the health and safety of patients and dental staff.

Knowledge about methods of disinfection of dental impression among dentists from Ecuador post SARS-COV-2 pandemic

Purpose

The aim of this study is to evaluate the understanding of the management of methods and practices of disinfection of dental impressions applied by general dentists and specialists in oral rehabilitation, post SARS-COV-2 pandemic.

Introduction

The oral cavity has a favorable environment for the growth and multiplication of bacteria and viruses, serving as the gateway to viruses such as SARS CoV-2 virus. Given that patients may be hosts of this infectious disease, stricter biosecurity measures in dental offices and a better understanding of the disinfection processes of dental impressions should be considered in addition to avoiding cross-infections, which are very common in our work environment.

Materials and methods

Descriptive, analytical, survey with the topic "Methods and practices of disinfection of dental impressions" that was composed of 14 questions based in OHPD (Oral Health Preventive Dentistry), n = 452 respondents who met the following inclusion criteria: general practice dentists from Ecuador who actively take dental impressions, specialists in oral rehabilitation with 5 years of experience, surveys with information of complete items, n = 270 professionals; n = 192 general dentists, dental hygienist and n = 78 oral rehabilitation specialists.

Results

n = 270 professionals evaluated, with a mean of p = 0.0. At 426 responses with a p value of <0.05, 30.4 % of responses indicated ignorance in the management of dental impressions, with a standard deviation of 2.744, with significant differences between professions (p = 0.035) and higher average knowledge of sample management within specialist dentists, (Chi p = 0.410 p > 0.05).

Conclusion

The understanding of the management of dental impressions among general dentists and specialists in oral rehabilitation is limited.

Evaluation of the efficacy of hydroxyl radical (OH˙) release for disinfection of the air and surfaces in the dental clinic: an in vitro study

BACKGROUND

Concerning about the quality of room air has increased exponentially. Specially in dental clinics where diary practice is characterized by the important generation of aerosols.

MATERIAL AND METHODS

An in vitro model was used in which samples were collected from the surfaces and room air of a dental clinic before and after the use of an OH˙ radical generator.

RESULTS

A total of 1260 samples were collected for bacteriological analysis and 14 samples for the detection of SARS-CoV-2. Following OH˙ treatment, the tested surface samples showed a decrease in the number of colony forming units (CFUs) of 76.9% in TSA culture medium. The circulating room air samples in turn showed a decrease in CFUs of 66.7% in Sabouraud medium and 71.4% in Mannitol agar medium. No presence of SARS-CoV-2 was observed on the surface of the face shield.

CONCLUSIONS

The disinfectant technology based on the use of hydroxyl radicals (OH˙) is effective in reducing the presence of moulds and yeasts and Staphylococcus in the air, and in reducing total aerobic bacteria on the tested surfaces.

Effect of herbal mouthrinsein dental ultrasonic scalers among Indians

The use of herbal mouthrinse is gaining momentum in recent years. Therefore, it is of interest to evaluate the effect of 2 herbal mouthrinse (curcumin, cinnamon) in comparison with2 conventional mouthrinse (povidone iodine, chlorhexidine) when used as coolant in dental ultrasonic scalers. Hence, 200 participants were included in this study. Analysis of gingival index, periodontal index at baseline and one month follow up was completed. The inhibitory effects of both conventional and herbal mouth rinse in gingival health are similar. However, cinnamon and curcumin owing to its minimal adverse effects and low cost is useful as an alternative to chlorhexidine for reducing bacterial load in dental aerosols produced due to ultrasonic scalers.

Isolation Systems and its Effectiveness in Oral and Maxillofacial Surgery: A Systematic Review

Introduction

The success of restoration processes depends on the efficient control of moisture and microorganisms. Dental restorative procedures frequently use rubber dams as an isolation technique. There is still room for evidence-based discussion over how rubber dam use affects the durability and caliber of dental restorations. In this review, the effects of rubber dam isolation vs alternative isolation techniques for dental restorative procedures are compared.

Materials and Procedures

An extensive online search in the various databanks of the EMBASE, Medline, Pubmed, and Scopus was conducted. The keywords searched were "isolation, oral surgery, dental surgery, retractors, rubber dam, and methods of isolation." The studies selected were longitudinal research design and randomized trials. To ascertain the risk of bias, meta-analysis was carried out. The outcome was measured as the successful restoration at the end of follow-up period representing the thorough isolation.

Results

A total of 1342 people were involved in six studies from across the world that were carried out between 2010 and 2015. High bias risk existed in all the studies. Five investigations compared the rubber dam vs cotton rolls. Due to discrepancies in the data supplied, one study was omitted from the analysis. Three of the four trials that were still running showed restored survival rates with all having a follow-up of at least six months. The survival of the restored composite teeth for six months in rubber dam isolation with odds ratio of 2.29, 1.38, and 1.00 at the end of six months, one year and one and half year respectively. However, the evidence was very low and speculative. The isolation was seen effective in the primary teeth specifically for the proximal lesions. None of the included studies discussed side effects or provided information on the treatment's upfront costs.

Conclusion

The application of rubber dams in dental techniques may result in successful outcome compared to cotton rolls, according to some low-certainty evidence revealed in this research. Other times, the evidence is really ambiguous. It is necessary to conduct additional, high-quality studies investigating how rubber dam use affects various restorative procedures.

Evaluating the microbial aerosol generated by dental instruments: addressing new challenges for oral healthcare in the hospital infection

BACKGROUND

Using a rotary instrument or ultrasonic instrument for tooth preparation is a basic operation in the dental clinic that can produce a significant number of droplets and aerosols. The dental droplet and aerosol can lead to the transfer of harmful germs. The goal of this study was to analyze the properties of microbiological aerosol created by droplets and aerosol generated by three common tooth-preparation instruments.

METHODS

Streptococcus mutans UA159 was used as the biological tracer to visualize the droplets and aerosols. The passive sampling method was used to map the three-dimensional spatial distribution and the six-stage Andersen microbial sampler (AMS) was used as the active sampling method to catch aerosol particles at a specific time.

RESULTS

The aerosol concentration is related to instruments, three-dimensional spatial distribution, and dissipation time. Most aerosols were generated by air turbines. More microorganisms are concentrated at the 1.5 m plane. The majority of the post dental procedure contamination was detected within the 0-10-min period and it decreased rapidly within 30 min.

CONCLUSION

This study is conducive to the proposal and improvement of relevant infection control measures in dental procedures and provides a basis for the assessment of measures, reducing the risk of nosocomial infection.

Disinfection of the air and surfaces in the dental clinic using hydroxyl radical (OH-) based technology: A systematic review

Background

A systematic review was carried out to compare the disinfectant capacity of hydroxyl radicals (OH-) versus other products commonly used for disinfecting the air and surfaces.

Material and Methods

A literature search was made of the Cochrane Library, PubMed (MEDLINE) and Scopus databases. "In vitro" studies evaluating disinfection methods applicable to several surfaces and room air were included in the search. The search was carried out in April 2022, with no restrictions in terms of language or publication date.

Results

Of the 308 articles identified from the initial search, 8 were included for the quantitative analysis. All publications corresponded to experimental "in vitro" studies. Seven of them evaluated biocidal action against bacteria, and only two assessed activity against viral loads. The generation of contaminants secondary to application of the disinfectants was only analyzed in one of the studies, with the conclusion that the production of peroxyl radicals (RO2) derived from the oxidation of volatile organic compounds (VOCs) is greater when chemical surface disinfectants are used versus air disinfection systems.

Conclusions

The disinfection capacities of the currently available methods are similar, and none of them are able to replace the use of additional physical protection measures. Key words:Disinfection methods, hydroxyl radical, environment, surfaces, dentistry.

Microbial Air Contamination in a Dental Setting Environment and Ultrasonic Scaling in Periodontally Healthy Subjects: An Observational Study

The risk of microbial air contamination in a dental setting, especially during aerosol-generating dental procedures (AGDPs), has long been recognized, becoming even more relevant during the COVID-19 pandemic. However, individual pathogens were rarely studied, and microbial loads were measured heterogeneously, often using low-sensitivity methods. Therefore, the present study aimed to assess microbial air contamination in the dental environment, identify the microorganisms involved, and determine their count by active air sampling at the beginning (T0), during (T1), and at the end (T2) of ultrasonic scaling in systemically and periodontally healthy subjects. Air microbial contamination was detected at T0 in all samples, regardless of whether the sample was collected from patients treated first or later; predominantly Gram-positive bacteria, including Staphylococcus and Bacillus spp. and a minority of fungi, were identified. The number of bacterial colonies at T1 was higher, although the species found were similar to that found during the T0 sampling, whereby Gram-positive bacteria, mainly Streptococcus spp., were identified. Air samples collected at T2 showed a decrease in bacterial load compared to the previous sampling. Further research should investigate the levels and patterns of the microbial contamination of air, people, and the environment in dental settings via ultrasonic scaling and other AGDPs and identify the microorganisms involved to perform the procedure- and patient-related risk assessment and provide appropriate recommendations for aerosol infection control.

Development of a Novel Tabletop Device With Suction and Sanitization of Droplets against COVID-19

Background Coronavirus disease 2019 and other viruses are transmissible by aerosols and droplets from infected persons. This study aimed to develop a portable device that can trap droplets and deactivate viruses, and verify whether the device in an enclosed room can suction droplets and sanitize them using a filter and an ultraviolet-C (UVC) light-emitting diode. Materials and methods The portable device was evaluated by placing it 50 cm away from the droplet initiation point. A particle image velocimetry laser dispersed into a sheet form was used to visualize the droplets splashed on the irradiated sagittal plane and captured using a charge-coupled device camera at 60 frames per second. The images were overlaid and calculated to determine the percentage of the droplets beyond the portable device. Droplets with a particle size larger than 50 µm that dispersed and were deposited more than 100 cm away were measured using a water-sensitive paper. The effect of UVC sanitization on viruses captured by a high-efficiency particulate air (HEPA) filter was determined using a plaque assay. Results The percentage of droplets was 13.4% and 1.1% with the portable device OFF and ON, respectively, indicating a 91.8% reduction. The deposited droplets were 86 pixels and 26 pixels with the portable device OFF and ON, respectively, indicating a 68.7% reduction. The UVC deactivated more than 99% of the viruses on the HEPA filter surface in 5 minutes. Conclusions Our novel portable device can suck and fall the dispersed droplets, and an active virus was not observed on the exhaust side.

Mouth shield to minimize airborne transmission risk of COVID-19 and other infectious diseases in the dental office

Transmission of coronavirus disease (COVID-19) and other infectious diseases is a significant risk during dental procedures because most dental interventions involve aerosols or droplets that could contaminate the surrounding environment. Current protection guidelines to address the high risk of droplets, aerosols, and airborne particle transmission of COVID-19 in the dental office recommend minimizing aerosol-generating procedures. In this paper, an innovative mouth shield is presented that should minimize water backsplash from the air-water syringe during dental treatment. The mouth shield can be added to the personal protective equipment to provide the dental team with extra protection. It can be made of different materials, is straightforward, inexpensive, and safe to fabricate, and is easy to use.

Droplet Distribution in a University Dental Clinic Setting: The Importance of High-Volume Evacuation

The purpose of this study is to compare droplet distribution during a piezoelectric ultrasonic debridement procedure using either high-volume or slow-volume evacuation. Droplet distribution during a crown preparation with slow-volume evacuation is also examined. Fluorescein dye is added to the water reservoir and the procedures are performed by a single operator for 15 min on a dental manikin with artificial upper and lower teeth. Placement of filter paper squares (10 cm × 10 cm) in radiating lines away from the oral cavity of the dental manikin allows for visualization of droplet dispersion. Results show minimal difference in the spread of the droplets between the two evacuators during the debridement procedure; however, the slow-volume evacuator produces a higher concentration of droplets than the high-volume evacuator. An even higher concentration of droplets in the vicinity of the dental chair is observed during the crown preparation procedure. This study recommends the use of a high-volume evacuator where possible during professional debridement and crown preparation to reduce contamination around the dental chair from potentially pathogenic microorganisms.

Preprocedural mouth rinses for preventing transmission of infectious diseases through aerosols in dental healthcare providers

BACKGROUND

Aerosols and spatter are generated in a dental clinic during aerosol-generating procedures (AGPs) that use high-speed hand pieces. Dental healthcare providers can be at increased risk of transmission of diseases such as tuberculosis, measles and severe acute respiratory syndrome (SARS) through droplets on mucosae, inhalation of aerosols or through fomites on mucosae, which harbour micro-organisms. There are ways to mitigate and contain spatter and aerosols that may, in turn, reduce any risk of disease transmission. In addition to personal protective equipment (PPE) and aerosol-reducing devices such as high-volume suction, it has been hypothesised that the use of mouth rinse by patients before dental procedures could reduce the microbial load of aerosols that are generated during dental AGPs.

OBJECTIVES

To assess the effects of preprocedural mouth rinses used in dental clinics to minimise incidence of infection in dental healthcare providers and reduce or neutralise contamination in aerosols.

SEARCH METHODS

We used standard, extensive Cochrane search methods. The latest search date was 4 February 2022.

SELECTION CRITERIA

We included randomised controlled trials and excluded laboratory-based studies. Study participants were dental patients undergoing AGPs. Studies compared any preprocedural mouth rinse used to reduce contaminated aerosols versus placebo, no mouth rinse or another mouth rinse. Our primary outcome was incidence of infection of dental healthcare providers and secondary outcomes were reduction in the level of contamination of the dental operatory environment, cost, change in mouth microbiota, adverse events, and acceptability and feasibility of the intervention.

DATA COLLECTION AND ANALYSIS

Two review authors screened search results, extracted data from included studies, assessed the risk of bias in the studies and judged the certainty of the available evidence. We used mean differences (MDs) and 95% confidence intervals (CIs) as the effect estimate for continuous outcomes, and random-effects meta-analysis to combine data  MAIN RESULTS:  We included 17 studies with 830 participants aged 18 to 70 years. We judged three trials at high risk of bias, two at low risk and 12 at unclear risk of bias.  None of the studies measured our primary outcome of the incidence of infection in dental healthcare providers.  The primary outcome in the studies was reduction in the level of bacterial contamination measured in colony-forming units (CFUs) at distances of less than 2 m (intended to capture larger droplets) and 2 m or more (to capture droplet nuclei from aerosols arising from the participant's oral cavity). It is unclear what size of CFU reduction represents a clinically significant amount. There is low- to very low-certainty evidence that chlorhexidine (CHX) may reduce bacterial contamination, as measured by CFUs, compared with no rinsing or rinsing with water. There were similar results when comparing cetylpyridinium chloride (CPC) with no rinsing and when comparing CPC, essential oils/herbal mouthwashes or boric acid with water. There is very low-certainty evidence that tempered mouth rinses may provide a greater reduction in CFUs than cold mouth rinses. There is low-certainty evidence that CHX may reduce CFUs more than essential oils/herbal mouthwashes. The evidence for other head-to-head comparisons was limited and inconsistent.  The studies did not provide any information on costs, change in micro-organisms in the patient's mouth or adverse events such as temporary discolouration, altered taste, allergic reaction or hypersensitivity. The studies did not assess acceptability of the intervention to patients or feasibility of implementation for dentists.  AUTHORS' CONCLUSIONS: None of the included studies measured the incidence of infection among dental healthcare providers. The studies measured only reduction in level of bacterial contamination in aerosols. None of the studies evaluated viral or fungal contamination. We have only low to very low certainty for all findings. We are unable to draw conclusions regarding whether there is a role for preprocedural mouth rinses in reducing infection risk or the possible superiority of one preprocedural rinse over another. Studies are needed that measure the effect of rinses on infectious disease risk among dental healthcare providers and on contaminated aerosols at larger distances with standardised outcome measurement.

Are aerosol control devices effective in preventing the spread of dental aerosol?

Background

In dental clinics, aerosols produced from dental instruments have become a matter of concern following breakout of coronavirus disease 19 (COVID-19) evolving into a pandemic. This study compared aerosol reduction systems and in terms of their ability to reduce Enterococcus faecalis (E. faecalis) contaminated aerosol in a simulated dental office set-up.

Methods

Closed clinic model with manikin and mandibular molar typodont was simulated. For 10 min, the air and water dispersed by the rotating bur mounted on an aerator was contaminated by pouring the suspension containing 1-3 × 10⁸ CFU/mL E. faecalis directly on the bur. During and after the procedures, the air within the cabin was also sampled. CFU count was recorded and scored. The mean CFU scores obtained from agar plate count and air sampling device was compared using Kruskal-Wallis H test among groups with 5% significance threshold.

Results

The use of WS Aerosol Defender device led to greater CFU scores on the agars levelled to patient's chest compared to other directions (p = 0.001). Combined use of VacStation and WS Aerosol Defender resulted in significantly decreased CFU score in the air samples compared to experimental and positive control groups (p = 0 < 0.05).

Conclusions

Although the devices prevented the spread of aerosol around the patient to some extent, they could not completely eliminate the contaminated aerosol load in the cabin environment.

CHX and a Face Shield Cannot Prevent Contamination of Surgical Masks

Background

Bacterial contamination on surgical masks puts a threat to medical staff and patients. The aim of the study was to investigate its contamination during dental treatments, wearing a face shield and performing a pre-procedural mouth rinsing with chlorhexidine (CHX).

Methods

In this prospective, randomized study, 306 treatments were included, 141 single-tooth (restorations) and 165 total dentition treatments (preventive or periodontal supportive ultrasonic application). A total of three groups (each: n = 102) were formed: participants rinsed for 60 s with 0.1 % CHX or with water before treatment, and, for control, a non-rinsing group was included. In view of the COVID-19 pandemic, a face shield covering the surgical mask enhanced personal protective equipment. After treatment, masks were imprinted on agar plates and incubated at 35°C for 48 h. Bacteria were classified by phenotypic characteristics, biochemical assay methods, and matrix-assisted laser desorption/ionization time of flight mass spectrometry (MALDI-TOF MS). Colonies (CFU) were counted and mean values were compared (Kruskal–Wallis-, U test, p < 0.05).

Results

Chlorhexidine led to a statistically significant reduction of bacterial contamination of the surgical mask (mean: 24 CFU) in comparison with water (mean: 47 CFU) and non-rinsing (mean: 80 CFU). Furthermore, rinsing with water reduced CFU significantly in comparison with the non-rinsing group. There were no significant differences between single or total dentition treatments. Streptococcus spp., Staphylococcus spp., Micrococcus spp., and Bacillus spp. dominated, representing the oral and cutaneous flora.

Conclusion

A pre-procedural mouth rinse is useful to reduce the bacterial load of the surgical mask. However, contamination cannot be prevented completely, even by applying a face shield. In particular, during pandemic, it is important to consider that these additional protective measures are not able to completely avoid the transmission of pathogens bearing aerosols to the facial region. If antiseptic rinsing solutions are not available, rinsing with water is also useful.

Efficacy of Combining an Extraoral High-Volume Evacuator with Preprocedural Mouth Rinsing in Reducing Aerosol Contamination Produced by Ultrasonic Scaling

The coronavirus disease pandemic has afforded dental professionals an opportunity to reconsider infection control during treatment. We investigated the efficacy of combining extraoral high-volume evacuators (eHVEs) with preprocedural mouth rinsing in reducing aerosol contamination by ultrasonic scalers. A double-masked, two-group, crossover randomized clinical trial was conducted over eight weeks. A total of 10 healthy subjects were divided into two groups; they received 0.5% povidone-iodine (PI), essential oil (EO), or water as preprocedural rinse. Aerosols produced during ultrasonic scaling were collected from the chest area (PC), dentist's mask, dentist's chest area (DC), bracket table, and assistant's area. Bacterial contamination was assessed using colony counting and adenosine triphosphate assays. With the eHVE 10 cm away from the mouth, bacterial contamination by aerosols was negligible. With the eHVE 20 cm away, more dental aerosols containing bacteria were detected at the DC and PC. Mouth rinsing decreased viable bacterial count by 31-38% (PI) and 22-33% (EO), compared with no rinsing. The eHVE prevents bacterial contamination when close to the patient's mouth. Preprocedural mouth rinsing can reduce bacterial contamination where the eHVE is positioned away from the mouth, depending on the procedure. Combining an eHVE with preprocedural mouth rinsing can reduce bacterial contamination in dental offices.

Workplace interventions to reduce the risk of SARS-CoV-2 infection outside of healthcare settings

BACKGROUND

Although many people infected with SARS-CoV-2 (severe acute respiratory syndrome coronavirus-2) experience no or mild symptoms, some individuals can develop severe illness and may die, particularly older people and those with underlying medical problems. Providing evidence-based interventions to prevent SARS-CoV-2 infection has become more urgent with the spread of more infectious SARS-CoV-2 variants of concern (VoC), and the potential psychological toll imposed by the coronavirus disease 2019 (COVID-19) pandemic.   Controlling exposures to occupational hazards is the fundamental method of protecting workers. When it comes to the transmission of viruses, such as SARS-CoV-2, workplaces should first consider control measures that can potentially have the most significant impact. According to the hierarchy of controls, one should first consider elimination (and substitution), then engineering controls, administrative controls, and lastly, personal protective equipment (PPE).

OBJECTIVES

To assess the benefits and harms of interventions in non-healthcare-related workplaces to reduce the risk of SARS-CoV-2 infection relative to other interventions, or no intervention.

SEARCH METHODS

We searched MEDLINE, Embase, Web of Science, Cochrane COVID-19 Study Register, the Canadian Centre for Occupational Health and Safety (CCOHS), Clinicaltrials.gov, and the International Clinical Trials Registry Platform to 14 September 2021. We will conduct an update of this review in six months.

SELECTION CRITERIA

We included randomised control trials (RCT) and planned to include non-randomised studies of interventions. We included adult workers, both those who come into close contact with clients or customers (e.g. public-facing employees, such as cashiers or taxi drivers), and those who do not, but who could be infected by co-workers. We excluded studies involving healthcare workers. We included any intervention to prevent or reduce workers' exposure to SARS-CoV-2 in the workplace, defining categories of intervention according to the hierarchy of hazard controls, i.e. elimination; engineering controls; administrative controls; personal protective equipment.

DATA COLLECTION AND ANALYSIS

We used standard Cochrane methods. Our primary outcomes were incidence rate of SARS-CoV-2 infection (or other respiratory viruses), SARS-CoV-2-related mortality, adverse events, and absenteeism from work. Our secondary outcomes were all-cause mortality, quality of life, hospitalisation, and uptake, acceptability, or adherence to strategies. We used the Cochrane RoB 2 tool to assess the risk of bias, and GRADE methods to assess the certainty of evidence for each outcome.

MAIN RESULTS

Elimination of exposure interventions We included one study examining an intervention that focused on elimination of hazards. This study is an open-label, cluster-randomised, non-inferiority trial, conducted in England in 2021. The study compared standard 10-day self-isolation after contact with an infected person to a new strategy of daily rapid antigen testing and staying at work if the test is negative (test-based attendance). The trialists hypothesised that this would lead to a similar rate of infections, but lower COVID-related absence. Staff (N = 11,798) working at 76 schools were assigned to standard isolation, and staff (N = 12,229) at 86 schools to the test-based attendance strategy.  The results between test-based attendance and standard 10-day self-isolation were inconclusive for the rate of symptomatic PCR-positive SARS-COV-2 infection rate ratio ((RR) 1.28, 95% confidence interval (CI) 0.74 to 2.21; 1 study, very low-certainty evidence)). The results between test-based attendance and standard 10-day self-isolation were inconclusive for the rate of any PCR-positive SARS-COV-2 infection (RR 1.35, 95% CI 0.82 to 2.21; 1 study, very low-certainty evidence). COVID-related absenteeism rates were 3704 absence days in 566,502 days-at-risk (6.5 per 1000 days at risk) in the control group and 2932 per 539,805 days-at-risk (5.4 per 1000 days at risk) in the intervention group (RR 0.83; 95% CI 0.55 to 1.25). The certainty of the evidence was downgraded to low, due to imprecision. Uptake of the intervention was 71 % in the intervention group, but not reported for the control intervention.  The trial did not measure other outcomes, SARS-CoV-2-related mortality, adverse events, all-cause mortality, quality of life, and hospitalisation. We found one ongoing RCT about screening in schools, using elimination of hazard strategies. Personal protective equipment We found one ongoing non-randomised study on the effects of closed face shields to prevent COVID-19 transmission. Other intervention categories We did not find studies in the other intervention categories.

AUTHORS' CONCLUSIONS

We are uncertain whether a test-based attendance policy affects rates of PCR-postive SARS-CoV-2 infection (any infection; symptomatic infection) compared to standard 10-day self-isolation amongst school and college staff. Test-based attendance policy may result in little to no difference in absence rates compared to standard 10-day self-isolation. As a large part of the population is exposed in the case of a pandemic, an apparently small relative effect that would not be worthwhile from the individual perspective may still affect many people, and thus, become an important absolute effect from the enterprise or societal perspective.  The included study did not report on any other primary outcomes of our review, i.e. SARS-CoV-2-related mortality and adverse events. No completed studies were identified on any other interventions specified in this review, but two eligible studies are ongoing. More controlled studies are needed on testing and isolation strategies, and working from home, as these have important implications for work organisations.

Efficacy of Aerosol Reduction Measures for Dental Aerosol Generating Procedures

Aerosol particles generated by dental procedures could facilitate the transmission of infectious diseases and contain carcinogen particles. Such particles can penetrate common surgical masks and reach the lungs, leading to increased risk for dental care professionals. However, the risk of inhaling contaminated aerosol and the effectiveness of aerosol reduction measures in dental offices remain unclear. The present study aimed to quantify aerosols produced by drilling and scaling procedures and to evaluate present recommendations for aerosol reduction. The concentration of aerosol particles released from the mock scaling and drilling procedures on dental mannequin were measured using a TSI Optical Particle Sizer (OPS 3330) during 15-min sessions carried out in a single-patient examination room. Using a drilling procedure as the aerosol source, the aerosol reduction performance of two types of high-volume evacuators (HVEs) and a commercial off-the-shelf air purifier was evaluated in a simulated clinical setting. Using either HVEs or the air purifier individually reduced the aerosol accumulated over the course of a 15-minutes drilling procedure at a reduction rate of 94.8 to 97.6%. Using both measures simultaneously raised the reduction rate to 99.6%. The results show that existing HVEs can effectively reduce aerosol concentration generated by a drilling procedure and can be further improved by using an air purifier. Following current regulatory guidelines can ensure a low risk of inhaling contaminated aerosol for dentists, assistants, and patients.

Pros and Cons of CAD/CAM Technology for Infection Prevention in Dental Settings during COVID-19 Outbreak

The purpose of this commentary is to update the evidence reported in our previous review on the advantages and limitations of computer-aided design/computer-aided manufacturing technology in the promotion of dental business, as well as to guarantee patient and occupational safety. The COVID-19 pandemic led to an unprecedented focus on infection prevention; however, waves of COVID-19 follow one another, asymptomatic cases are nearly impossible to identify by triage in a dental setting, and the effectiveness of long-lasting immune protection through vaccination remains largely unknown. Different national laws and international guidelines (mainly USA-CDC, ECDC) have often brought about dissimilar awareness and operational choices, and in general, there has been very limited attention to this technology. Here, we discuss its advantages and limitations in light of: (a) presence of SARS-CoV-2 in the oral cavity, saliva, and dental biofilm and activation of dormant microbial infections; (b) the prevention of SARS-CoV-2 transmission by aerosol and fomite contamination; (c) the detection of various oral manifestations of COVID-19; (d) specific information for the reprocessing of the scanner tip and the ward from the manufacturers.

Preprocedural mouth rinses can reduce bacterial contamination in aerosols during periodontal prophylaxis

Aim This study evaluates the effectiveness of preprocedural mouth rinsing when performing non-surgical periodontal prophylaxis to reduce bacterial aerosol contamination.

Data sources The authors used the population, intervention, control and outcomes (PICO) question format to perform a systematic online search in Scopus, PubMed, Cochrane Library and Web of Science. All the databases were explored with no time limit until April 2020.

Study selection Randomised clinical trials were included in this systematic review. No inclusion or exclusion criteria are mentioned in this study and it is limited to bacterial contamination studies.

Data extraction and synthesis The authors extracted the following information from the included studies: authors; article publication year; study design; sampling size and allocation of test and control groups; intervention details; type and description of periodontal prophylaxis procedures; and primary outcomes. They focused on statistically significant findings and the reduction of bacterial aerosol contamination between groups was measured by colony forming units (CFU) using means and percentages. The primary outcome was that bacterial count expressed as CFU on blood agar plates. If permissible, they calculated the mean CFU reduction in the included studies and reported them. The authors also assessed the studies' risk of bias using the revised Cochrane risk of bias tool for randomised trials.

Results In total, 30 randomised controlled trials were included, 21 of which assessed the preprocedural rinsing and the remaining nine focused on other interventions. The bacterial incubation protocol differed among studies. The data collection sites differed among the studies in terms of the number of samples obtained, position, direction and distance from the subjects' mouths. There were no marked differences in the CFU reduction regarding the periodontal prophylaxis devices used and the location of aerosol sampling collection from these studies. Nearly half of the studies (52.4%, 11/21) collected the sample at or near the operator and dental assistant. Chlorhexidine (CHX) rinse was mostly tested (80.9%, 17/21) with various concentrations and volumes. Among studies comparing CHX with other agents (71.4%, 15/21), CHX was more effective for the better part of studies, with more than half of the studies (7/15) reporting over a 70% reduction in CFU when using CHX preprocedural mouth rinse.

Conclusions Evidence corroborates the effectiveness of preprocedural mouth rinses, especially CHX, in reducing the bacterial contamination of aerosols in periodontal, non-surgical prophylaxis compared with mouth rinsing with water, or with no rinsing. Nevertheless, the low-quality of evidence and the high heterogeneity among the included studies warn that one should be cautious in generalising the findings of this study to other settings and contaminating agents, like viruses. The findings of this study emphasise the need for more studies on the efficacy and effectiveness of preprocedural rinses in reducing the viral load in aerosols (and droplets) during periodontal prophylaxis procedures.

Removal and dispersal of biofluid films by powered medical devices: Modeling infectious agent spreading in dentistry

Medical procedures can disperse infectious agents and spread disease. Particularly, dental procedures may pose a high risk of disease transmission as they use high-powered instruments operating within the oral cavity that may contain infectious microbiota or viruses. Here we assess the ability of powered dental devices in removing the biofluid films and identified mechanical, hydrodynamic, and aerodynamic forces as the main underlying mechanisms of removal and dispersal processes. Our results indicate that potentially infectious agents can be removed and dispersed immediately after dental instrument engagement with the adherent biofluid film, while the degree of their dispersal is rapidly depleted owing to the removal of the source and dilution by the coolant water. We found that droplets created by high-speed drill interactions typically travel ballistically, while aerosol-laden air tends to flow as a current over surfaces. Our mechanistic investigation offers plausible routes for reducing the spread of infection during invasive medical procedures.

•

Mechanical, hydrodynamic, and aerodynamic forces drive removal/dispersal processes

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The air-rotor has the highest ability to remove and disperse infectious agents

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The aerosol cloud flows as a current and continuously settles

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Manipulating rheological properties of the fluids can suppress aerosol generation

Oral bacterial decontamination using an innovative prototype for photocatalytic disinfection

OBJECTIVES

The aim of this study was to evaluate the effectiveness of a prototype photocatalytic device for bacterial decontaminations of the oral cavity.

METHODS

Sixty-four subjects (18-65) were selected and randomly assigned to eight groups (n = 8), according to oral disinfection protocol: (G1): distilled water (control); (G2): 1.5% hydrogen peroxide (HP); (G3): 3.0% HP; (G4): 0.12% chlorhexidine (CHX); (G5): Germinator; (G6): 1.5% HP + Germinator; (G7): 3.0%HP + Germinator; (G8): 0.12% CHX + Germinator. Stimulated saliva was collected before and after a 3-min mouthwash and/or Germinator application. The patients were kept relaxed and retained saliva 5-10 min, spitting out into the tube for 3 min. The percentage bacterial reduction was checked by counting the colony-forming units (CFUs) after culturing on blood agar plates. Data were subjected to one-way ANOVA followed by Tukey's post hoc test (α = 5%) for statistical significance.

RESULTS

The highest bacterial reduction was observed in groups 3 (3.0% HP), 6 (1.5% HP + Germinator), and 7 (3.0% + Germinator), with no statistically significant difference between them (p > 0.05). Groups 6 (1.5% HP + Germinator) and 8 (0.12% CHX + Germinator) showed higher bacterial reduction than groups 2 (1.5% HP) and 4 (0.12% CHX) (p < 0.05). Finally, group 5 (Germinator) showed higher bacterial reduction than control group (DW) and group 4 (0.12% CHX) (p < 0.05).

CONCLUSIONS

The photocatalytic disinfection was effective against oral bacteria and improved the antimicrobial action of 1.5% HP and 0.12%.

CLINICAL SIGNIFICANCE

The photocatalytic disinfection can be an alternative protocol to provide the oral decontamination.

The Spread of Droplets and Aerosols of Surgical Motor Handpiece Irrigation Using Different Suction Systems

Objective: This study aimed to compare the effectiveness of various combinations of dental suction devices in reducing the amount and distance of spread of aerosols and droplets using an electrical surgical motor model with a self-irrigation system.

Materials and Methods: In a standard single-chaired air-conditioned ventilated dental clinic, an electrical dental surgical motor with a high-speed handpiece (Implantmed) cooled with 0.2% fluorescein containing normal saline was used to drill a gypsum block mounted on a phantom head in a supine position. A single operator performed thrice each of the following suction settings: (a) no suction, (b) low-volume suction, (c) low-volume + high-volume suctions, and (d) low-volume + external oral suctions. Aerosols (0.1–5 μm) were measured with a particle counter at the mouth opening of the phantom head, and droplet sizes and distances were analyzed via a machine learning algorithm by identifying fluorescence droplets on pre-loaded pieces of paper on the floor for each group.

Results: The different suction systems have different performances in terms of droplet distance (p = 0.007), whereas using (c) high volume suctions (41.1 ± 22.9 cm) and (d) external oral suction unit (39 ± 18.2 cm) had significantly reduced the spread of droplets when compared with (a) without suction (58.9 ± 17.1 cm). Using (d) external oral suction or (c) high volume suction could reduce the number for all droplet sizes. The use of (c) high volume suction was most effective in reducing aerosol count of 0.3–1 μm, while (d) external oral suction was most effective in reducing aerosol count of 3–5 μm.

Conclusions: Both external oral suction and high-volume suction were effective in reducing aerosols and droplets generated by the irrigation of a surgical high-speed motor handpiece. External oral suction could be an effective alternative to high volume suction in dental surgical procedures to reduce the spread of aerosols and droplets.

Clinical Relevance: External oral suction or high-volume suction should be used in conjunction with low-volume suction in surgical procedure to reduce the spread of aerosols and droplets in a dental clinic environment.

Implications for clinical dental practice during the coronavirus disease pandemic: A scoping review

PURPOSE

It is over a year since the first case of coronavirus disease (COVID-19) was confirmed in China. This paper reviews and summarizes the characteristics of COVID-19, as understood of December 2020, from a dental perspective.

STUDY SELECTION

The PubMed and Scopus online databases were searched using a combination of free words and Medical Subject Headings terms: "dentist" OR "oral care" AND "COVID-19" OR "SARS-CoV-2."

RESULTS

Older people and those with underlying medical conditions have an increased risk of serious illness due to COVID-19. The virus enters the body by binding to the angiotensin-converting enzyme 2 (ACE2) receptor. It is common for people with COVID-19 to have mild or no symptoms. Moreover, the disease is not contagious in most infected people; it is only highly contagious in some infected people, thereby forming clusters. Due to the large number of virus particles that are shed prior to the onset of symptoms of the disease, retrospective surveys are important. Appropriate personal protective equipment against corona vortices is also important in clinical practice. Although polymerase chain reaction tests are useful for confirming infection in suspected individuals, their reliability is questionable. In addition, concerns regarding long-term sequelae have been reported.

CONCLUSIONS

There are few high-quality reports on the implications of COVID-19 in dental practice. However, reports suggest that insufficient oral hygiene may be a risk factor for infection. Reports that ACE2 receptors are abundant in the oral cavity also suggest the importance of oral care.

Air Quality in a Dental Clinic during Er:YAG Laser Usage for Cavity Preparation on Human Teeth-An Ex-Vivo Study

Chemical air pollution in dental clinics consists of the emission of gases and particulate matter (PM), both generated by dental equipment and tooth tissues. One basic application of Erbium Laser devices is cavity preparation on human teeth due to its strong affinity to water and hydroxyapatite. The objective of this study was the evaluation of indoor air quality during the application of an Er:YAG laser, as a dentin removal instrument, in a Dental Clinic. Particulate Matter (PM) was measured using the standard method of EN legislation. In order to measure total Volatile Organic compounds (VOCs), a portable monitor was used. In the first experiment, PM10 and PM2.5 concentrations were increased by approximately 10 and 15 times, respectively. From the second experiment it can be concluded that neither of the measured particle concentrations exceeded the recommended indoor limit values while windows were open, although laser influence was still detectable. Within the limitations applied herein, it was found that Er:YAG laser activity for hard dental tissue removal was associated with high PM and TVOCs concentration values in the working environment, under insufficient or no ventilation. Physical ventilation in the aforementioned setting proved to be an important key factor in improving air quality, as both PM and TVOCs concentrations decreased significantly.

Spray mist reduction by means of a high-volume evacuation system-Results of an experimental study

OBJECTIVES

High-speed tooth preparation requires effective cooling to avoid thermal damage, which generates spray mist, which is a mixture of an aerosol, droplets and particles of different sizes. The aim of this experimental study was to analyze the efficacy of spray mist reduction with an intraoral high-volume evacuation system (HVE) during simulated high-speed tooth preparation for suboptimal versus optimal suction positions of 16 mm sized cannulas and different flow rates of the HVE.

MATERIAL AND METHODS

In a manikin head, the upper first premolar was prepared with a dental turbine, and generated particles of 5-50 microns were analyzed fifty millimeters above the mouth opening with the shadow imaging technique (frame: 6.6×5.3×1.1 mm). This setup was chosen to generate a reproducible spray mist in a vertical direction towards an imaginary operator head (worst case scenario). The flow rate (FR) of the HVE was categorized into five levels (≤120 l/min up to 330 l/min). The number of particles per second (NP; p/s) was counted, and the mass volume flow of particles per second (MVF; μg/s*cm3) was calculated for 10 sec. Statistical tests were nonparametric and two-sided (p≤0.05).

RESULTS

With increasing flow rate, the NP/MVF values decreased significantly (eta: 0.671/0.678; p≤0.001). Using a suboptimally positioned cannula with an FR≤160 l/min, significantly higher NP values (mean±SD) of 731.67±54.24 p/s (p≤0.019) and an MVF of 3.72±0.42 μg/s*cm3 (p≤0.010) were measured compared to those of the optimal cannula position and FR≥300 l/min (NP/MVF: 0/0). No significant difference in NP and MVF was measurable between FR≥250 l/min and FR>300 l/min (p = 0.652, p = 0.664).

CONCLUSION

Within the limitations of the current experimental study, intraoral high-flow rate suction with ≥300 l/min with an HVE effectively reduced 5-50 μm sized particles of the spray mist induced by high-speed tooth preparation with a dental turbine.

Delivery of Health Care by Spanish Dental Hygienists in Private and Public Dental Services during the COVID-19 De-Escalation Phase (June 2020): A Cross-Sectional Study

Background: The first wave of the COVID-19 pandemic in Spain posed a major challenge for Spanish dental professionals. The objective of this work is to describe the dental hygienists’ work status and employment patterns during the de-escalation phase in order to analyse the standards of knowledge, compliance with official recommendations, and dental activities both in the public health service and in the private sector. Material and Methods: A cross-sectional questionnaire was answered by Spanish dental hygienists via WhatsApp, Facebook, and Instagram. The questionnaire was piloted before it was distributed and carried out during June 2020. Results: Here, 517 dental hygienists were surveyed, of which 86.2% followed the official recommendations to avoid contagion and 63.8% agreed with the gradual return to work by limiting the use of aerosols. Private dental hygienists identified more with returning to work without restrictions (14.5%) versus those working for the public service (1.2%) (p < 0.005). Conclusions: Dental hygienists’ return to work has involved different strategies, aimed at controlling infection and guaranteeing the safety of patients and the rest of the dental team. The availability of personal protective equipment, the adaptation of clinical infrastructure, and patient care management have differed between professionals working in the private and public sectors.

Profiling of Oral Microbiota and Cytokines in COVID-19 Patients

The presence of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) has been recently demonstrated in the sputum or saliva, suggesting how the shedding of viral RNA outlasts the end of symptoms. Recent data from transcriptome analysis show that the oral cavity mucosa harbors high levels of angiotensin-converting enzyme 2 (ACE2) and transmembrane protease, serine 2 (TMPRSS2), highlighting its role as a double-edged sword for SARS-CoV-2 body entrance or interpersonal transmission. Here, we studied the oral microbiota structure and inflammatory profile of 26 naive severe coronavirus disease 2019 (COVID-19) patients and 15 controls by 16S rRNA V2 automated targeted sequencing and magnetic bead-based multiplex immunoassays, respectively. A significant diminution in species richness was observed in COVID-19 patients, along with a marked difference in beta-diversity. Species such as Prevotella salivae and Veillonella infantium were distinctive for COVID-19 patients, while Neisseria perflava and Rothia mucilaginosa were predominant in controls. Interestingly, these two groups of oral species oppositely clustered within the bacterial network, defining two distinct Species Interacting Groups (SIGs). COVID-19-related pro-inflammatory cytokines were found in both oral and serum samples, along with a specific bacterial consortium able to counteract them. We introduced a new parameter, named CytoCOV, able to predict COVID-19 susceptibility for an unknown subject at 71% of power with an Area Under Curve (AUC) equal to 0.995. This pilot study evidenced a distinctive oral microbiota composition in COVID-19 subjects, with a definite structural network in relation to secreted cytokines. Our results would be usable in clinics against COVID-19, using bacterial consortia as biomarkers or to reduce local inflammation.

Current systematic reviews and meta-analyses of COVID-19

BACKGROUND

Coronavirus disease 2019 (COVID-19) has left a significant impact on the world's health, economic and political systems; as of November 20, 2020, more than 57 million people have been infected worldwide, with over 1.3 million deaths. While the global spotlight is currently focused on combating this pandemic through means ranging from finding a treatment among existing therapeutic agents to inventing a vaccine that can aid in halting the further loss of life.

AIM

To collect all systematic reviews and meta-analyses published related to COVID-19 to better identify available evidence, highlight gaps in knowledge, and elucidate further meta-analyses and umbrella reviews that are yet to be performed.

METHODS

We explored studies based on systematic reviews and meta-analyses with the key-terms, including severe acute respiratory syndrome (SARS), SARS virus, coronavirus disease, COVID-19, and SARS coronavirus-2. The included studies were extracted from Embase, Medline, and Cochrane databases. The publication timeframe of included studies ranged between January 01, 2020, to October 30, 2020. Studies that were published in languages other than English were not considered for this systematic review. The finalized full-text articles are freely accessible in the public domain.

RESULTS

Searching Embase, Medline, and Cochrane databases resulted in 1906, 669, and 19 results, respectively, that comprised 2594 studies. 515 duplicates were subsequently removed, leaving 2079 studies. The inclusion criteria were systematic reviews or meta-analyses. 860 results were excluded for being a review article, scope review, rapid review, panel review, or guideline that produced a total of 1219 studies. After screening articles were categorized, the included articles were put into main groups of clinical presentation, epidemiology, screening and diagnosis, severity assessment, special populations, and treatment. Subsequently, there was a second subclassification into the following groups: gastrointestinal, cardiovascular, neurological, stroke, thrombosis, anosmia and dysgeusia, ocular manifestations, nephrology, cutaneous manifestations, D-dimer, lymphocyte, anticoagulation, antivirals, convalescent plasma, immunosuppressants, corticosteroids, hydroxychloroquine, renin-angiotensin-aldosterone system, technology, diabetes mellitus, obesity, pregnancy, children, mental health_, smoking, cancer, and transplant.

CONCLUSION

Among the included articles, it is clear that further research is needed regarding treatment options and vaccines. With more studies, data will be less heterogeneous, and statistical analysis can be better applied to provide more robust clinical evidence. This study was not designed to give recommendations regarding the management of COVID-19.

Effects of Natural Ventilation and Saliva Standard Ejectors during the COVID-19 Pandemic: A Quantitative Analysis of Aerosol Produced during Dental Procedures

The novel Coronavirus Disease 2019 (COVID-19) pandemic has renewed attention to aerosol-generating procedures (AGPs). Dental-care workers are at high risk of contamination by SARS-CoV-2. The aim of this study was to evaluate the efficacy of standard saliva ejectors and natural ventilation in reducing particulate matter (PM) concentration during different routine dental procedures in the pandemic period. The DustTrak monitor was used to measure PM1, PM2.5, PM10, and breathable (<4 microns) total dust during 14 procedures performed with and without the presence of natural ventilation in a dental unit. Moreover, measurements were performed near the practitioners or near the standard saliva ejectors during the different procedures. In the latter condition, reduced levels of PM10 were recorded (82.40 ± 9.65 μg/m³ vs. 50.52 ± 0.23 μg/m³). Moreover, higher levels of PM (53.95 ± 2.29 μg/m³ vs. 27.85 ± 0.14 μg/m³) were produced when the dental unit's windows were open. At the same time, the total level of PM were higher during scaling than during other procedures (data suggest not to adopt natural ventilation-both window and door opened-during dental procedures). It was also demonstrated that the use of standard saliva ejectors can considerably reduce the total released amount of PM10.

Do aspirating systems have a role in preventing COVID-19 transmission among dental healthcare workers?

Aim The aim of this retrospective cohort study was to determine and compare the seropositivity rates of SARS-CoV-2 among dental healthcare workers (HCWs) working in three different clinics using different types of aspirating systems. The study took place in Ekaterinburg (Russian Federation).

Methods A total of 157 HCWs from three different clinics (56, 60 and 41 HCWs, respectively) who worked during the COVID-19 pandemic period (May to August 2020) constituted the cohort. All of the three chosen clinics had followed COVID-19 screening, triage and other recommendations for safe practice. In addition to using personal protective equipment and other common barrier methods to lower virus transmission, these clinics were equipped with different types of aspirating systems that included V6000 used in dry mode, V6000 used in semi-dry mode and VS900, respectively. All HCWs underwent serological testing once a week to detect immunoglobulin G and M antibodies against SARS-CoV-2 using SARS-CoV-2-IgG-EIA-BEST and SARS-CoV-2-IgM-EIA-BEST enzyme immunoassay kits (Vector-Best).

Results An overall prevalence of seropositivity was observed to be 11.5% (19/157 HCWs) over a five-month follow-up. The prevalence of infection was not found to be associated with sex or the role of the member in the dental team (dentist/dental assistant). Significantly higher infection rates (p <0.001) were observed among HCWs working in the clinic equipped with the VS900 aspirating vacuum pump without HEPA filters, while the lowest infection rate was found among HCWs working in the clinic using the V6000 aspirating system in dry mode.

Conclusions HCWs working in the clinic equipped with an aspirating system which has HEPA filters and released the air into an external environment (V6000) exhibited significantly lower seroprevalence rates compared to HCWs in the clinic using an aspirating system without HEPA filters which released air within the dental operatory away from the operation site (VS900).

Awareness of aerosol-related transmission of COVID-19 among the dentists of Nepal

Objective

To access the awareness of dental practitioners of Nepal towards COVID-19 transmission through aerosols.

Materials and methods

The study involved 384 dentists from all over Nepal and was conducted for a period of 3 months. A self-reported online questionnaire was developed using Google forms and the link was shared. It emphasized the awareness related to the aerosol and ventilation system in their daily practices was prepared. The data were analyzed in Statistical Package for Social Sciences version 20.0 software.

Results

The majority of participants were female 52.9% (n = 203) and within the age groups of <30 years 57% (n = 219). Participants from Bagmati Province were 60.4% (n = 232), with least from Sudurpaschim Province 0.5% (n = 2). 60% of participants provided only emergency services during the COVID-19 pandemic and few (7%) provided consultations via telephone. The current ventilation system used was a well-ventilated room with open windows 65.4% (n = 251). However, 52.8% (n = 203) preferred specialized operatory incorporating high-efficiency particulate air (HEPA) filters and ultraviolet (UV) light. More than 60% of respondents were unaware of the particle size of the aerosol.

Conclusions

The obtained results signify the need for the proper ventilation system with appropriate air filtration systems in dental clinical setups.

A Review of Aerosol Generation Mitigation in International Dental Guidance

INTRODUCTION

The coronavirus disease 2019 (COVID-19) led to the worldwide closure of dental practices or reduction of dental services. By the end of April 2020, governments and professional organisations were publishing recommendations or guidance for the reopening/restructuring of dental services. The aim of this study was to assess how dental aerosol-generating procedures (AGPs) were defined in international dental guidelines, what mitigation processes were advised, and whether they were linked to COVID-19 epidemiology.

METHODS

Electronic searches of a broad range of databases, along with grey literature searches, without language restriction were conducted up to 13 July 2020. Recommendations for the use of face masks and fallow times with patients without COVID-19 were assessed against the deaths per 1 million population in the included countries and country income level using Pearson Chi-squared statistics.

RESULTS

Sixty-three guidance documents were included. Most (98%) indicated that AGPs can be performed with patients without COVID-19 with caveats, including advice to restrict AGPs where possible, with 21% only recommending AGPs for dental emergencies. Face masks were recommended by most documents (94%), with 91% also specifying the use of goggles or face shields. Fallow periods for patients without COVID-19 were mentioned in 48% of documents, ranging from 2 to 180 minutes. There were no significant differences in recommendations for face masks or fallow time in patients without COVID-19 by country death rate (P = .463 and P = .901) or World Bank status (P = .504 and P = .835). Most documents recommended procedural or environmental mitigations such as preprocedural mouthwash (82%) and general ventilation (52%). Few documents provided underpinning evidence for their recommendations.

CONCLUSIONS

While the amount of high-quality direct evidence related to dentistry and COVID-19 remains limited, it is important to be explicit about the considered judgements for recommendations as well as generate new evidence to face this challenge.

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

Objective/aim

To identify small particle concentrations (eight categories: ≤0.1 µm × ≤5.0 µm) induced by aerosol-generating procedures (AGPs; high-speed tooth preparation, ultrasonic scaling; air polishing) under high-flow suction with a 16-mm intraoral cannula with and without an additional mobile extraoral scavenger (EOS) device during student training.

Materials and methods

Twenty tests were performed (16.94 m² room without ventilation with constant temperature (26.7 (1.1) °C and humidity (56.53 (4.20)%)). Data were collected 2 min before, 2 min during, and 6 min after AGPs. The EOS device and the air sampler for particle counting were placed 0.35 m from the open mouth of a manikin head. The particle number concentration (PN, counts/m3) was measured to calculate ΔPN (ΔPN = [post-PN] − [pre-PN]).

Results

Mean ΔPN (SD) ranged between −8.65E+06 (2.86E+07) counts/m³ for 0.15 µm and 6.41E+04 (2.77E+05) counts/m³ for 1.0 µm particles. No significant differences were found among the AGP groups (p > 0.05) or between the AGP and control groups (p > 0.05). With an EOS device, lower ΔPN was detected for smaller particles by high-speed tooth preparation (0.1–0.3 µm; p < 0.001).

Discussion

A greater reduction in the number of smaller particles generated by the EOS device was found for high-speed tooth preparation. Low ΔPN by all AGPs demonstrated the efficacy of high-flow suction.

Conclusions

The additional use of an EOS device should be carefully considered when performing treatments, such as high-speed tooth preparation, that generate particularly small particles when more people are present and all other protective options have been exhausted.

Rubber dam isolation for restorative treatment in dental patients

BACKGROUND

The effective control of moisture and microbes is necessary for the success of restoration procedures. The rubber dam, as an isolation method, has been widely used in dental restorative treatments. The effects of rubber dam usage on the longevity and quality of dental restorations still require evidence-based discussion. This review compares the effects of rubber dam with other isolation methods in dental restorative treatments. This is an update of the Cochrane Review first published in 2016.

OBJECTIVES

To assess the effects of rubber dam isolation compared with other types of isolation used for direct and indirect restorative treatments in dental patients.

SEARCH METHODS

Cochrane Oral Health's Information specialist searched the following electronic databases: Cochrane Oral Health's Trials Register (searched 13 January 2021), Cochrane Central Register of Controlled Trials (CENTRAL; 2020, Issue 12) in the Cochrane Library (searched 13 January 2021), MEDLINE Ovid (1946 to 13 January 2021), Embase Ovid (1980 to 13 January 2021), LILACS BIREME Virtual Health Library (Latin American and Caribbean Health Science Information database; 1982 to 13 January 2021), and SciELO BIREME Virtual Health Library (1998 to 13 January 2021). We also searched Chinese BioMedical Literature Database (CBM, in Chinese) (1978 to 13 January 2021), VIP database (in Chinese) (1989 to 13 January 2021), and China National Knowledge Infrastructure (CNKI, in Chinese) (1994 to 13 January 2021). We searched ClinicalTrials.gov and the World Health Organization International Clinical Trials Registry Platform, OpenGrey, and Sciencepaper Online (in Chinese) for ongoing trials. There were no restrictions on the language or date of publication when searching the electronic databases.

SELECTION CRITERIA

We included randomised controlled trials (including split-mouth trials) over one month in length assessing the effects of rubber dam compared with alternative isolation methods for dental restorative treatments.

DATA COLLECTION AND ANALYSIS

Two review authors independently screened the results of the electronic searches, extracted data, and assessed the risk of bias of the included studies. Disagreement was resolved by discussion. We strictly followed Cochrane's statistical guidelines and assessed the certainty of the evidence using GRADE.

MAIN RESULTS

We included six studies conducted worldwide between 2010 and 2015 involving a total of 1342 participants (of which 233 participants were lost to follow-up). All the included studies were at high risk of bias. Five studies compared rubber dam with traditional cotton rolls isolation. One study was excluded from the analysis due to inconsistencies in the presented data. Of the four remaining trials, three reported survival rates of the restorations with a minimum follow-up of six months. Pooled results from two studies involving 192 participants indicated that the use of rubber dam isolation may increase the survival rates of direct composite restorations of non-carious cervical lesions (NCCLs) at six months (odds ratio (OR) 2.29, 95% confidence interval (CI) 1.05 to 4.99; low-certainty evidence). However, the use of rubber dam in NCCLs composite restorations may have little to no effect on the survival rates of the restorations compared to cotton rolls at 12 months (OR 1.38, 95% CI 0.45 to 4.28; 1 study, 30 participants; very low-certainty evidence) and at 18 months (OR 1.00, 95% CI 0.45 to 2.25; 1 study, 30 participants; very low-certainty evidence) but the evidence is very uncertain. At 24 months, the use of rubber dam may decrease the risk of failure of the restorations in children undergoing proximal atraumatic restorative treatment in primary molars but the evidence is very uncertain (hazard ratio (HR) 0.80, 95% CI 0.66 to 0.97; 1 study, 559 participants; very low-certainty evidence). None of the included studies mentioned adverse effects or reported the direct cost of the treatment.

AUTHORS' CONCLUSIONS

This review found some low-certainty evidence that the use of rubber dam in dental direct restorative treatments may lead to a lower failure rate of the restorations compared with cotton roll usage after six months. At other time points, the evidence is very uncertain. Further high-quality research evaluating the effects of rubber dam usage on different types of restorative treatments is required.

Oral Health Care Delivery for Children During COVID-19 Pandemic-A Retrospective Study

Aim: COVID-19 outbreak and the lockdown period following was a very challenging time for pediatric dentistry. We aimed to find whether the characteristics of dental care provided to children at the Department of Pediatric Dentistry at Hadassah medical center, Jerusalem, Israel, differed between the periods, before COVID-19 outbreak, during the lockdown period and during the period that followed it.

Materials and Methods: We retrospectively reviewed computerized records of patients who visited the pediatric dental clinic at three different periods: pre-lockdown period, lockdown period, and post-lockdown period.

Results: Nine-hundred and forty-nine children were included in the study; most of them were healthy children between 3 and 6 years old. During lockdown, all scheduled appointments except for treatments under general anesthesia and deep sedation were canceled due to the government's restrictions; the frequency of treatments with non-pharmacological behavior management, general anesthesia or deep sedation was higher than in the previous or subsequent periods and the use of inhaled/conscious sedation was significantly lower. During lockdown most of the children were diagnosed with dentoalveolar abscess (32.3%), compared to 14 and 21% at the previous or subsequent periods, respectively (P < 0.001). Treatments combination during lockdown included more extractions, pulpectomies and pulp extirpation and less permanent restorations (P < 0.001). None of the staff members was infected with COVID-19 at the clinic during these periods. We concluded that dentists should be updated about Covid-19 modes of transmission and the recommended infection control measures in dental settings. Effective management protocols can help the dental staff to continue to provide efficient treatment and prevent Covid-19 contamination.

Efficacy of personal protective equipment against coronavirus transmission via dental handpieces

BACKGROUND

This laboratory study was done to evaluate the efficacy of personal protective equipment (PPE) and high-volume evacuation (HVE) against the spread of human coronavirus type 229E (HCoV-229E) during a standard dental procedure.

METHODS

Patient and operator manikins were used to recreate a dental setting inside a custom-built class III cabinet-like chamber. The mouth of the patient manikin was inoculated with an HCoV-229E suspension, the viral load of which was similar to that of asymptomatic people infected with severe acute respiratory syndrome coronavirus 2. The dental procedure was performed with an air turbine handpiece and HVE for 10 seconds. The efficacy of surgical masks, N95 (filtering facepiece class 2) and filtering facepiece class 3 respirators, and face shields was tested via quantitative real-time polymerase chain reaction.

RESULTS

The wide surface on which the inoculum was spread caused low contamination. Over the external surfaces of masks and respirators, when a face shield was not worn, viral loads ranged from 1.2 through 1.4 log₁₀ mean gene copies per cm². When the shield was worn, viral loads dropped below the detection limit (< 0.317 log₁₀ gene copies/cm²) for all PPE. On the operator's forehead, viral loads were 0.6 through 0.8 log₁₀ gene copies/cm². Inside the operator manikin's mouth, viral loads were under the detection limit when using any PPE, with or without the shield. HVE did not significantly change viral loads.

CONCLUSIONS

All PPE combinations significantly reduced viral loads in the operator manikin's mouth to below the detection limit, but HVE did not decrease viral contamination.

PRACTICAL IMPLICATIONS

Although caution is suggested when removing and disposing of PPE to avoid self-contamination, the combination of PPE and face shields drastically decreases the risk of transmitting human coronavirus during aerosol-generating dental procedures.

Impact of the COVID-19 pandemic on urgent dental care delivery in a Swiss university center for dental medicine

Objectives

This study aimed to assess whether the emergency service of a major Swiss dental institution faced different demands (patient volume, treatment needs, dental care characteristics) during a lockdown, issued to mitigate the COVID-19 pandemic, compared with the weeks before and after.

Materials and methods

Data of patients receiving urgent care at a university center for dental medicine (Basel, Switzerland) during the 6-week lockdown, pre-lockdown, and post-lockdown periods were retrospectively evaluated. Statistical analysis involved tests for equal proportions and logistic regression models. The level of significance was set at α=0.05.

Results

The study comprised 3109 dental emergency visits in the period from February 2 to June 5, 2020. Daily caseloads increased during lockdown. Abscesses, orthodontic emergencies, and surgical follow-ups were more common during lockdown, whereas the number of dento-alveolar injuries declined (≤0.048). Urgent dental care provision involved intraoral radiographs more frequently in the pre-lockdown period compared with the following weeks (p<0.001). Among all treatments, aerosol-generating procedures dropped from 56.1% (pre-lockdown) to 21.3% during lockdown (p<0.001), while teledentistry follow-ups became more frequent (p<0.001). Patients with comorbidities sought urgent dental care less frequently during the post-lockdown period (p=0.004).

Conclusions

The lockdown significantly impacted the dental emergency service in terms of patients’ diagnoses, treatment needs, and the characteristics of the urgent care that was delivered.

Clinical relevance

Access to essential dental care must be monitored and safeguarded throughout the COVID-19 pandemic and beyond as deferred care entails risks for serious sequelae and persons with comorbidities may change their dental care-seeking behavior.

Splatters and Aerosols Contamination in Dental Aerosol Generating Procedures

Dental aerosol-generating procedures produce a large amount of splatters and aerosols that create a major concern for airborne disease transmission, such as COVID-19. This study established a method to visualise splatter and aerosol contamination by common dental instrumentation, namely ultrasonic scaling, air-water spray, high-speed and low-speed handpieces. Mock dental procedures were performed on a mannequin model, containing teeth in a typodont and a phantom head, using irrigation water containing fluorescein dye as a tracer. Filter papers were placed in 10 different locations to collect splatters and aerosols, at distances ranging from 20 to 120 cm from the source. All four types of dental equipment produced contamination from splatters and aerosols. At 120 cm away from the source, the high-speed handpiece generated the greatest amount and size (656 ± 551 μm) of splatter particles, while the triplex syringe generated the largest amount of aerosols (particle size: 1.73 ± 2.23 μm). Of note, the low-speed handpiece produced the least amount and size (260 ± 142 μm) of splatter particles and the least amount of aerosols (particle size: 4.47 ± 5.92 μm) at 120 cm. All four dental AGPs produce contamination from droplets and aerosols, with different patterns of distribution. This simple model provides a method to test various preventive strategies to reduce risks from splatter and aerosols.

Aerosols modification with H2O2 reduces airborne contamination by dental handpieces

Objective: We designed an in vitro study to evaluate the efficiency of an 0.5 vol% hydrogen peroxide-based spray in reducing Coronavirus 229E spread during a conventional dental procedure.

Methods: A class III cabinet-like chamber was custom-built, using phantoms for both patient and operator. A suspension of HCoV-229E in artificial saliva having a similar viral load to SARS-CoV-2 asymptomatic patients was inoculated inside the patient’s phantom mouth. A 10 s-lasting dental procedure was performed using an aerosol-generating air-turbine, with or without high-volume evacuation (HVE). The effect of 0.5 vol% H₂O₂ cooling spray in reducing viral loads was tested. Viral presence on the operator phantom was assessed by Real-Time quantitative PCR on the mask’s outer surface, on the phantom’s forehead, and inside its mouth.

Results: When the H₂O₂ cooling spray was used, as compared to the conventional spray, viral loads were significantly lower on all tested sites, falling below the detection limit. Viral loads did not significantly change in any tested site when HVE was used.

Conclusion: The use of 0.5 vol% H₂O₂ cooling spray by dental handpieces drastically reduced the possibility of coronaviruses spread during aerosol-generating dental procedures. This strategy deserves further consideration among the preventive measures to be adopted during the SARS-CoV-2 pandemic.

Paediatric dental care during and post-COVID-19 era: Changes and challenges ahead

Background

COVID-19 is an infectious disease caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). The virus is transmitted through respiratory droplets and by physical contact from contaminated surfaces to the mucosa. Its route of transmission has caused a significant challenge in medical and dental healthcare.

Objective

This article aims to review the literature and information available on the provision of paediatric dental treatment during and post-pandemic and to provide specific recommendations on the safe provision of paediatric dental care.

Results

Children infected by SARS-CoV-2 have no or milder COVID-19 symptoms and are potential vectors in spreading the disease. Routine dental treatment is suspended in many countries because of the increased risk of cross-infection in dental practices. Only emergency dental care is provided for urgent conditions. It is necessary to gradually reinstate regular dental care to paediatric patients and maintain their good oral health. To control the disease transmission and maintain the oral health of the population, minimally intervention techniques that minimise or eliminate aerosol generation, plus comprehensive oral health preventive measures should be practised to safeguard safety at dental practices in this unprecedented time.

Conclusions

Robust infection control guidelines should be implemented in dental clinics to minimise the risk of infection and to ensure the safety of patients and staff during the pandemic. Three levels of preventive care should be practised to prevent oral diseases and improve children's oral health in this COVID-19 era. Treatment should be prioritized to patients in urgent needs and aerosol-generating procedures should be minimized.

Recall intervals for oral health in primary care patients

BACKGROUND

There is ongoing debate about the frequency with which patients should attend for a dental check-up and the effects on oral health of the interval between check-ups. Recommendations regarding optimal recall intervals vary between countries and dental healthcare systems, but 6-month dental check-ups have traditionally been advocated by general dental practitioners in many high-income countries. This review updates a version first published in 2005, and updated in 2007 and 2013.

OBJECTIVES

To determine the optimal recall interval of dental check-up for oral health in a primary care setting.

SEARCH METHODS

Cochrane Oral Health's Information Specialist searched the following databases: Cochrane Oral Health's Trials Register (to 17 January 2020), the Cochrane Central Register of Controlled Trials (CENTRAL; in the Cochrane Library, 2019, Issue 12), MEDLINE Ovid (1946 to 17 January 2020), and Embase Ovid (1980 to 17 January 2020). We also searched the US National Institutes of Health Trials Registry (ClinicalTrials.gov) and the World Health Organization International Clinical Trials Registry Platform for ongoing trials. We placed no restrictions on the language or date of publication when searching.

SELECTION CRITERIA

We included randomised controlled trials (RCTs) assessing the effects of different dental recall intervals in a primary care setting.

DATA COLLECTION AND ANALYSIS

Two review authors screened search results against inclusion criteria, extracted data and assessed risk of bias, independently and in duplicate. We contacted study authors for clarification or further information where necessary and feasible. We expressed the estimate of effect as mean difference (MD) with 95% confidence intervals (CIs) for continuous outcomes and risk ratios (RR) with 95% CIs for dichotomous outcomes. We assessed the certainty of the evidence using GRADE.

MAIN RESULTS

We included two studies with data from 1736 participants. One study was conducted in a public dental service clinic in Norway and involved participants under 20 years of age who were regular attenders at dental appointments. It compared 12-month with 24-month recall intervals and measured outcomes at two years. The other study was conducted in UK general dental practices and involved adults who were regular attenders, which was defined as having attended the dentist at least once in the previous two years. It compared the effects of 6-month, 24-month and risk-based recall intervals, and measured outcomes at four years. The main outcomes we considered were dental caries, gingival bleeding and oral-health-related quality of life. Neither study measured other potential adverse effects. 24-month versus 12-month recall at 2 years' follow-up Due to the very low certainty of evidence from one trial, it is unclear if there is an important difference in caries experience between assignment to a 24-month or a 12-month recall. For 3- to 5-year-olds with primary teeth, the mean difference (MD) in dmfs (decayed, missing, and filled tooth surfaces) increment was 0.90 (95% CI -0.16 to 1.96; 58 participants). For 16- to 20-year-olds with permanent teeth, the MD in DMFS increment was 0.86 (95% CI -0.03 to 1.75; 127 participants). The trial did not assess other clinical outcomes of relevance to this review. Risk-based recall versus 6-month recall at 4 years' follow-up We found high-certainty evidence from one trial of adults that there is little to no difference between risk-based and 6-month recall intervals for the outcomes: number of tooth surfaces with any caries (ICDAS 1 to 6; MD 0.15, 95% CI -0.77 to 1.08; 1478 participants); proportion of sites with gingival bleeding (MD 0.78%, 95% CI -1.17% to 2.73%; 1472 participants); oral-health-related quality of life (MD in OHIP-14 scores -0.35, 95% CI -1.02 to 0.32; 1551 participants). There is probably little to no difference in the prevalence of moderate to extensive caries (ICDAS 3 to 6) between the groups (RR 1.04, 95% CI 0.99 to 1.09; 1478 participants; moderate-certainty evidence). 24-month recall versus 6-month recall at 4 years' follow-up We found moderate-certainty evidence from one trial of adults that there is probably little to no difference between 24-month and 6-month recall intervals for the outcomes: number of tooth surfaces with any caries (MD -0.60, 95% CI -2.54 to 1.34; 271 participants); percentage of sites with gingival bleeding (MD -0.91%, 95% CI -5.02% to 3.20%; 271 participants). There may be little to no difference between the groups in the prevalence of moderate to extensive caries (RR 1.05, 95% CI 0.92 to 1.20; 271 participants; low-certainty evidence). We found high-certainty evidence that there is little to no difference in oral-health-related quality of life between the groups (MD in OHIP-14 scores -0.24, 95% CI -1.55 to 1.07; 305 participants). Risk-based recall versus 24-month recall at 4 years' follow-up We found moderate-certainty evidence from one trial of adults that there is probably little to no difference between risk-based and 24-month recall intervals for the outcomes: prevalence of moderate to extensive caries (RR 1.06, 95% CI 0.95 to 1.19; 279 participants); number of tooth surfaces with any caries (MD 1.40, 95% CI -0.69 to 3.49; 279 participants). We found high-certainty evidence that there is no important difference between the groups in the percentage of sites with gingival bleeding (MD -0.07%, 95% CI -4.10% to 3.96%; 279 participants); or in oral-health-related quality of life (MD in OHIP-14 scores -0.37, 95% CI -1.69 to 0.95; 298 participants).

AUTHORS' CONCLUSIONS

For adults attending dental check-ups in primary care settings, there is little to no difference between risk-based and 6-month recall intervals in the number of tooth surfaces with any caries, gingival bleeding and oral-health-related quality of life over a 4-year period (high-certainty evidence). There is probably little to no difference between the recall strategies in the prevalence of moderate to extensive caries (moderate-certainty evidence). When comparing 24-month with either 6-month or risk-based recall intervals for adults, there is moderate- to high-certainty evidence that there is little to no difference in the number of tooth surfaces with any caries, gingival bleeding and oral-health-related quality of life over a 4-year period. The available evidence on recall intervals between dental check-ups for children and adolescents is uncertain. The two trials we included in the review did not assess adverse effects of different recall strategies.

Interventions to reduce contaminated aerosols produced during dental procedures for preventing infectious diseases

BACKGROUND

Many dental procedures produce aerosols (droplets, droplet nuclei and splatter) that harbour various pathogenic micro-organisms and may pose a risk for the spread of infections between dentist and patient. The COVID-19 pandemic has led to greater concern about this risk.

OBJECTIVES

To assess the effectiveness of methods used during dental treatment procedures to minimize aerosol production and reduce or neutralize contamination in aerosols.

SEARCH METHODS

Cochrane Oral Health's Information Specialist searched the following databases on 17 September 2020: Cochrane Oral Health's Trials Register, the Cochrane Central Register of Controlled Trials (CENTRAL) (in the Cochrane Library, 2020, Issue 8), MEDLINE Ovid (from 1946); Embase Ovid (from 1980); the WHO COVID-19 Global literature on coronavirus disease; the US National Institutes of Health Trials Registry (ClinicalTrials.gov); and the Cochrane COVID-19 Study Register. We placed no restrictions on the language or date of publication.

SELECTION CRITERIA

We included randomized controlled trials (RCTs) and controlled clinical trials (CCTs) on aerosol-generating procedures (AGPs) performed by dental healthcare providers that evaluated methods to reduce contaminated aerosols in dental clinics (excluding preprocedural mouthrinses). The primary outcomes were incidence of infection in dental staff or patients, and reduction in volume and level of contaminated aerosols in the operative environment. The secondary outcomes were cost, accessibility and feasibility.

DATA COLLECTION AND ANALYSIS

Two review authors screened search results, extracted data from the included studies, assessed the risk of bias in the studies, and judged the certainty of the available evidence. We used mean differences (MDs) and 95% confidence intervals (CIs) as the effect estimate for continuous outcomes, and random-effects meta-analysis to combine data. We assessed heterogeneity.

MAIN RESULTS

We included 16 studies with 425 participants aged 5 to 69 years. Eight studies had high risk of bias; eight had unclear risk of bias. No studies measured infection. All studies measured bacterial contamination using the surrogate outcome of colony-forming units (CFU). Two studies measured contamination per volume of air sampled at different distances from the patient's mouth, and 14 studies sampled particles on agar plates at specific distances from the patient's mouth. The results presented below should be interpreted with caution as the evidence is very low certainty due to heterogeneity, risk of bias, small sample sizes and wide confidence intervals. Moreover, we do not know the 'minimal clinically important difference' in CFU. High-volume evacuator Use of a high-volume evacuator (HVE) may reduce bacterial contamination in aerosols less than one foot (~ 30 cm) from a patient's mouth (MD -47.41, 95% CI -92.76 to -2.06; 3 RCTs, 122 participants (two studies had split-mouth design); very high heterogeneity I² = 95%), but not at longer distances (MD -1.00, -2.56 to 0.56; 1 RCT, 80 participants). One split-mouth RCT (six participants) found that HVE may not be more effective than conventional dental suction (saliva ejector or low-volume evacuator) at 40 cm (MD CFU -2.30, 95% CI -5.32 to 0.72) or 150 cm (MD -2.20, 95% CI -14.01 to 9.61). Dental isolation combination system One RCT (50 participants) found that there may be no difference in CFU between a combination system (Isolite) and a saliva ejector (low-volume evacuator) during AGPs (MD -0.31, 95% CI -0.82 to 0.20) or after AGPs (MD -0.35, -0.99 to 0.29). However, an 'n of 1' design study showed that the combination system may reduce CFU compared with rubber dam plus HVE (MD -125.20, 95% CI -174.02 to -76.38) or HVE (MD -109.30, 95% CI -153.01 to -65.59). Rubber dam One split-mouth RCT (10 participants) receiving dental treatment, found that there may be a reduction in CFU with rubber dam at one-metre (MD -16.20, 95% CI -19.36 to -13.04) and two-metre distance (MD -11.70, 95% CI -15.82 to -7.58). One RCT of 47 dental students found use of rubber dam may make no difference in CFU at the forehead (MD 0.98, 95% CI -0.73 to 2.70) and occipital region of the operator (MD 0.77, 95% CI -0.46 to 2.00). One split-mouth RCT (21 participants) found that rubber dam plus HVE may reduce CFU more than cotton roll plus HVE on the patient's chest (MD -251.00, 95% CI -267.95 to -234.05) and dental unit light (MD -12.70, 95% CI -12.85 to -12.55). Air cleaning systems One split-mouth CCT (two participants) used a local stand-alone air cleaning system (ACS), which may reduce aerosol contamination during cavity preparation (MD -66.70 CFU, 95% CI -120.15 to -13.25 per cubic metre) or ultrasonic scaling (MD -32.40, 95% CI - 51.55 to -13.25). Another CCT (50 participants) found that laminar flow in the dental clinic combined with a HEPA filter may reduce contamination approximately 76 cm from the floor (MD -483.56 CFU, 95% CI -550.02 to -417.10 per cubic feet per minute per patient) and 20 cm to 30 cm from the patient's mouth (MD -319.14 CFU, 95% CI - 385.60 to -252.68). Disinfectants ‒ antimicrobial coolants Two RCTs evaluated use of antimicrobial coolants during ultrasonic scaling. Compared with distilled water, coolant containing chlorhexidine (CHX), cinnamon extract coolant or povidone iodine may reduce CFU: CHX (MD -124.00, 95% CI -135.78 to -112.22; 20 participants), povidone iodine (MD -656.45, 95% CI -672.74 to -640.16; 40 participants), cinnamon (MD -644.55, 95% CI -668.70 to -620.40; 40 participants). CHX coolant may reduce CFU more than povidone iodine (MD -59.30, 95% CI -64.16 to -54.44; 20 participants), but not more than cinnamon extract (MD -11.90, 95% CI -35.88 to 12.08; 40 participants).

AUTHORS' CONCLUSIONS

We found no studies that evaluated disease transmission via aerosols in a dental setting; and no evidence about viral contamination in aerosols. All of the included studies measured bacterial contamination using colony-forming units. There appeared to be some benefit from the interventions evaluated but the available evidence is very low certainty so we are unable to draw reliable conclusions. We did not find any studies on methods such as ventilation, ionization, ozonisation, UV light and fogging. Studies are needed that measure contamination in aerosols, size distribution of aerosols and infection transmission risk for respiratory diseases such as COVID-19 in dental patients and staff.