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

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.

Dental Surgical Activity in Hospitals during COVID-19: A Nationwide Observational Cohort Study

INTRODUCTION

The number of surgical extractions performed in hospitals in England remains unclear. This study reports the volume of surgical extractions conducted in hospitals and change in activity during the COVID-19 pandemic.

METHODS

We conducted a nationwide observational cohort study using Hospital Episode Statistics (HES) in England for patients undergoing surgical removal of a tooth (defined using OPSC-4 code F09) between April 1, 2015, and December 31, 2020. Procedures were stratified by age, gender, and urgency (elective or nonelective), reported using descriptive statistics, number, and percentage. We conducted post hoc modeling to predict surgical activity to December 2023. In addition, we contrasted this with aggregate national data on simple dental extraction procedures and drainage of dental abscesses in hospital as well as dental activity in general practice.

RESULTS

We identified a total of 569,938 episodes for the surgical removal of a tooth (females 57%). Of these, 493,056/569,938 (87%) were for adults and 76,882/569,938 (13%) children ≤18 years. Surgical extractions were most frequent in adult females. Elective cases accounted for 96% (n = 548,805/569,938) of procedures. The median number of procedures carried out per quarter was 27,256, dropping to 12,003 during the COVID-19 pandemic, representing a 56% reduction in activity. This amounted to around 61,058 cancelled procedures. Modeling predicts that this activity has not returned to prepandemic levels.

CONCLUSIONS

The number of surgical extractions taking place in hospitals during the pandemic fell by 56%. The true impact of this reduction is unknown, but delayed treatment increases the risk of complications, including life-threatening infections.

KNOWLEDGE TRANSFER STATEMENT

The result of this study provides an evidence-based overview of the trends relating to surgical extractions of teeth in England taking place in hospitals. This information can be used to inform service and workforce planning to meet the needs of patients requiring surgical extractions. The data also provide an insight into the oral health needs of the population in England.

High-volume evacuation mitigates viral aerosol spread in dental procedures

Dental healthcare personnel (DHCP) are subjected to microbe-containing aerosols and splatters in their everyday work. Safer work conditions must be developed to ensure the functioning of the healthcare system. By simulating dental procedures, we aimed to compare the virus-containing aerosol generation of four common dental instruments, and high-volume evacuation (HVE) in their mitigation. Moreover, we combined the detection of infectious viruses with RT-qPCR to form a fuller view of virus-containing aerosol spread in dental procedures. The air-water syringe produced the highest number of aerosols. HVE greatly reduced aerosol concentrations during procedures. The air-water syringe spread infectious virus-containing aerosols throughout the room, while other instruments only did so to close proximity. Additionally, infectious viruses were detected on the face shields of DHCP. Virus genomes were detected throughout the room with all instruments, indicating that more resilient viruses might remain infectious and pose a health hazard. HVE reduced the spread of both infectious viruses and viral genomes, however, it did not fully prevent them. We recommend meticulous use of HVE, a well-fitting mask and face shields in dental procedures. We advise particular caution when operating with the air-water syringe. Due to limited repetitions, this study should be considered a proof-of-concept report.

Single Institute Audit of Maxillofacial Trauma Cases Before and During COVID-19 Pandemic

Study Design

In the year 2020, we saw the emergence of severe acute respiratory syndrome coronavirus 2 causing COVID-19 into a full blown pandemic. This resulted in constraints on healthcare resources, and the attention was shifted to reduce cross contamination and prevent spreader events. Maxillofacial trauma care was also affected similarly, and most of the cases were managed by closed reduction whenever possible. A retrospective study was conducted to document our experience in treating maxillofacial trauma cases before and after nationwide lockdown due to COVID-19 pandemic in India.

Objective

The objective of the study was to compare the effect of pandemic in reported pattern of mandibular trauma and the result of closed reduction procedures in the management of single or multiple fractures in mandible during this time period.

Methods

The study was conducted in the Department of Oral and Maxillofacial Surgery, Maulana Azad institute of Dental Sciences, Delhi, for a period of 20 months, that is, 10 months before and after nationwide lock down which was effective from 23rd March 2020 due to COVID-19 pandemic. The cases were grouped into Group A (those reporting from 1st June 2019 to 31st March 2020) and Group B (those reporting from 1st April 2020 to 31st January 2021). Primary objectives were assessed and compared according to etiology, gender, location of the mandibular fractures, and treatment provided. Quality of life (QoL) associated with the treatment outcome by closed reduction was assessed after 2 months as a secondary objective using General Oral Health Assessment Index (GOHAI) in Group B.

Results

A total of 798 patients sought treatment for mandibular fractures and included 476 patients in Group A and 322 in Group B. The groups showed similar age and male: female ratio. Cases showed a steep fall during first wave of pandemic, and most of the cases occurred as result of RTA followed by fall and assault. The fractures due to fall and assault showed an obvious rise during the lockdown period. There were 718 (89.97%) patients having exclusive mandibular fractures and 80 (10.03%) patients having involvement of both mandible and maxilla. Single fractures of mandible constituted 110 (23.11%) and 58 (18.01%) in Group A and B, respectively. 324 patients (68.07%) and 226 patients (70.19%) had multiple fractures involving mandible in respective groups. Parasymphysis of mandible was most commonly involved (24.31%) followed closely by unilateral condyle (23.48%) then Angle and Ramus of mandible (20.71%) with coronoid being the least fractured. During the initial 6 months after lockdown, all the cases were treated successfully using closed reduction. GOHAI QoL assessment conducted in cases having exclusive mandibular fracture (210 Multiple, 48 Single) showed favorable results with significant (P < .05) difference between the single and multiple fractures.

Conclusions

After one and half years and recovering from the second wave of pandemic that hit the country, we have come to understand COVID-19 better and embraced better management protocol. The study reveals that IMF remains the gold standard for the management of most of the facial fractures in pandemic situations. It was evident from the QoL data that most of the patients were able to carry out their day-to-day functions adequately. As the country prepares for a third wave of pandemic, management of maxillofacial trauma by closed reduction will remain the norm for most unless indicated otherwise.

Evaluation of aerosols in a simulated orthodontic debanding procedure

Dental practitioners may be at risk for exposure to severe acute respiratory syndrome corona virus 2 when performing aerosol generating procedures. Though recent evidence suggests that coronavirus may be transmitted through aerosol generating procedures, it is unknown whether common procedures performed in dental clinics generate aerosol. The aim of this study was to simultaneously quantify airborne concentrations of the bacteriophage MS2 near the oral cavity of a dental mannequin and behind personal protective equipment (i.e., face shield) of the practitioner during a simulated orthodontic debanding procedure. A deband was performed eight times on a dental mannequin. Optical particle counters and SKC Biosamplers were used to measure particle concentration and to collect virus aerosol generated during the procedure, both near the oral cavity and behind the orthodontists face shield. A plaque assay was used to determine the viable virus airborne concentration. When comparing the two measuring locations, near the oral cavity and behind the clinician's face shield, there was no statistically significant difference of virus concentrations or particle size distribution. This study suggests that debanding under these conditions generates live virus aerosol and a face shield does not provide increased protection from virus aerosol, but does provide some protection against splatter during the procedure.

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.

Aerosol concentrations and size distributions during clinical dental procedures

Background

Suspected aerosol-generating dental instruments may cause risks for operators by transmitting pathogens, such as the SARS-CoV-2 virus. The aim of our study was to measure aerosol generation in various dental procedures in clinical settings.

Methods

The study population comprised of 84 patients who underwent 253 different dental procedures measured with Optical Particle Sizer in a dental office setting. Aerosol particles from 0.3 to 10 μm in diameter were measured. Dental procedures included oral examinations (N = 52), restorative procedures with air turbine handpiece (N = 8), high-speed (N = 6) and low-speed (N = 30) handpieces, ultrasonic scaling (N = 31), periodontal treatment using hand instruments (N = 60), endodontic treatment (N = 12), intraoral radiographs (N = 24), and dental local anesthesia (N = 31).

Results

Air turbine handpieces significantly elevated <1 μm particle median (p = 0.013) and maximum (p = 0.016) aerosol number concentrations as well as aerosol particle mass concentrations (p = 0.046 and p = 0.006) compared to the background aerosol levels preceding the operation. Low-speed dental handpieces elevated >5 μm median (p = 0.023), maximum (p = 0.013) particle number concentrations,> 5 μm particle mass concentrations (p = 0.021) and maximum total particle mass concentrations (p = 0.022). High-speed dental handpieces elevated aerosol concentration levels compared to the levels produced during oral examination.

Conclusions

Air turbine handpieces produced the highest levels of <1 μm aerosols and total particle number concentrations when compared to the other commonly used instruments. In addition, high- and low-speed dental handpieces and ultrasonic scalers elevated the aerosol concentration levels compared to the aerosol levels measured during oral examination. These aerosol-generating procedures, involving air turbine, high- and low-speed handpiece, and ultrasonic scaler, should be performed with caution.

Clinical significance

Aerosol generating dental instruments, especially air turbine, should be used with adequate precautions (rubber dam, high-volume evacuation, FFP-respirators), because aerosols can cause a potential risk for operators and substitution of air turbine for high-speed dental handpiece in poor epidemic situations should be considered to reduce the risk of aerosol transmission.

Challenges and Opportunities for Dental Education from COVID-19

With the ongoing COVID-19 pandemic, dental education has been profoundly affected by this crisis. First of all, COVID-19 brought physical and psychological health problems to dental students and educators. In addition, both non-clinical teaching and clinical-based training experienced challenges, ranging from fully online educational content to limited dental training, students’ research was delayed in achieving project milestones and there was hesitancy in respect of the COVID-19 vaccine. On the other hand, the COVID-19 pandemic has increased the demand for teledentistry and dental emergency treatment, and brought awareness of the advantages and high-speed development of distance education. This review aims to present these challenges and opportunities for dental education, and suggest how dental institutions should prepare for the future demand for dental education.

Child and parent preferences for the appearance of dentists with respect to personal protective equipment in paediatric dentistry

BACKGROUND

Personal protective equipment (PPE) gained particular importance during the COVID-19 pandemic.

AIM

To assess child and parent preferences for dentists' appearance concerning their PPE and to determine the relationship between the child and parent preferences.

DESIGN

A total of 250 children aged 6-12 years and their parents were enrolled in the study. Standardized pictures with different sexes, attires, eye protectors, hair protectors, masks, and gloves were shown to children and their parents separately, and they were asked to choose their preferences. The dental anxiety of the children and their parents was determined using the MCDAS_f and MDAS, respectively. Decayed, missing, and filled tooth (DMFT) indices were employed for the children.

RESULTS

Children and parents preferred a dentist of the same sex as themselves (p < .05). Anxious children preferred cartoon-printed attire, and children with low anxiety mostly preferred white coats (p = .001). Children who preferred colored coats had higher DMFT (p < .001). Statistically significant differences were found in the attire and glove preferences between children and parents (p < .001).

CONCLUSIONS

The production of white and child-friendly fluid-resistant disposable gowns should be considered. PPE with colored or cartoon print was preferred under the influence of factors that could positively affect anxiety.

Particle Size Analysis in Aerosol-Generating Dental Procedures Using Laser Diffraction Technique

The global outbreak of coronavirus disease 2019 (COVID-19) has raised concerns about the risk of airborne infection during dental treatment. Aerosol-generating dental procedures (AGDP) produce droplets and aerosols, but the details of the risks of COVID-19 transmission in AGDP are not well-understood. By discriminating between droplets and aerosols, we devised a method to measure particle size using laser diffraction analysis and evaluated aerosols generated from dental devices for providing a basis for proper infection control procedures. The droplets and aerosols generated from dental devices were characterized by multimodal properties and a wide range of droplet sizes, with the majority of droplets larger than 50 μm. AGDP emitted few aerosols smaller than 5 μm, which are of concern for pulmonary infections due to airborne transmission. In addition, the use of extraoral suction was found to prevent the spread of aerosols from high-speed dental engines. This study suggests that the risk of aerosol infections is considerably limited in regular dental practice and that current standard precautions, such as mainly focusing on protection against droplet and contact infections, are sufficient. While several cases of airborne transmission of COVID-19 in general clinics and emergency hospitals have been reported, cluster outbreaks in dental clinics have not yet been reported, which may indicate that AGDP does not pose a significant threat in contributing to the spread of SARS-CoV-2.