Significance of chlorine-dioxide-based oral rinses in preventing SARS-CoV-2 cell entry.

OBJECTIVE: This work aims to determine the efficacy of preprocedural oral rinsing with chlorine dioxide solutions to minimize the risk of coronavirus disease 2019 (COVID-19) transmission during high-risk dental procedures. METHODS: The antiviral activity of chlorine-dioxide-based oral rinse (OR) solutions was tested by pre-incubating with severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) pseudovirus in a dosage-dependent manner before transducing to human embryonic kidney epithelial (HEK293T-ACE2) cells, which stably expresses ACE-2 receptor. Viral entry was determined by measuring luciferase activity using a luminescence microplate reader. In the cell-to-cell fusion assay, effector Chinese hamster ovary (CHO-K1) cells co-expressing spike glycoprotein of SARS-CoV-2 and T7 RNA polymerase were pre-incubated with the ORs before co-culturing with the target CHO-K1 cells co-expressing human ACE2 receptor and luciferase gene. The luciferase signal was quantified 24 h after mixing the cells. Surface expression of SARS-CoV-2 spike glycoprotein and ACE-2 receptor was confirmed using direct fluorescent imaging and quantitative cell-ELISA. Finally, dosage-dependent cytotoxic effects of ORs were evaluated at two different time points. RESULTS: A dosage-dependent antiviral effect of the ORs was observed against SARS-CoV-2 cell entry and spike glycoprotein mediated cell-to-cell fusion. This demonstrates that ORs can be useful as a preprocedural step to reduce viral infectivity. CONCLUSIONS: Chlorine-dioxide-based ORs have a potential benefit for reducing SARS-CoV-2 entry and spread.

Aerosols in Ultrasonic Instrumentation: Comparison of particle spread utilizing saliva ejectors versus high-volume evacuation

Purpose: The emergence of SARS-CoV-2 has generated renewed interest in the potential transmission of viral contaminants via ultrasonic scaler-generated aerosols. The purpose of this study was to use controlled experimental conditions to quantify the range, direction, and concentration of aerosolized and splatter droplet spread across distances up to 106 inches from the source of the ultrasonic scaling procedure on a manikin patient head. Methods: A dental simulation unit (DSU) was used to facilitate ultrasonic instrumentation performed on a typodont located within a manikin patient head. A 9 x 9-foot section of white paper was placed on the floor directly beneath the DSU. White paper was also placed on the adjacent countertops for identification of possible spread. Methylene blue dye was mixed with reverse-osmosis (RO) water and placed in the reservoir of the ultrasonic scaler. Experimental tests were run with high-volume evacuation (HVE) and a with a saliva ejector. Photographs of the paper and droplets were taken and analyzed by computer software to identify all droplets captured on the paper. Results: Particle counts show that HVE use is associated with a reduction in total particle count for each zone evaluated, with the largest reduction seen in regions closest to the origin. Using HVE on the DSU demonstrated a 99% reduction in particles and 50% reduction in the range of particles. Conclusion: Dental health care providers should use HVE when generating aerosols during ultrasonic instrumentation procedures to reduce particle spread in health care settings.

Ultrasonic scaling in COVID-era dentistry: A quantitative assessment of aerosol spread during simulated and clinical ultrasonic scaling procedures.

OBJECTIVE: Healthcare agencies recommend limited use of aerosol-generating procedures to mitigate disease (COVID-19) transmission. However, total dispersion patterns of aerosols, particularly respirable droplets, via dental ultrasonic units is unclear. The purpose of this study was to characterize and map total spatter, droplet and aerosol dispersion during ultrasonic scaling in simulated and clinical contexts. METHODS: Ultrasonic scaling was performed on dental simulation units using methylene blue dye-stained water. All resultant stain profiles were photoanalysed to calculate droplet size and travel distance/direction. Airborne particle concentrations were also documented 0-1.2 m (0-4ft.) and 1.2-2.4 m (4-8ft.) from patients during in vivo ultrasonic scaling with a saliva ejector. RESULTS: Stain profiles showed droplets between 25 and 50µm in diameter were most common, with smaller droplets closer to the mouth. In-vivo particle concentrations were uniformly low. The smallest (<1 µm, PM1) and largest (>10 µm, PM10+) particles were most common, especially within 1.2 m (4ft.) of the patient. Respirable particles (PM2.5) were uncommon. CONCLUSIONS: Tests showed the highest concentration of small droplets in zones nearest the patient. While uncommon, particles were detected up to 2.4 m (8ft.) away. Furthermore, observed particle sizes were consistent with those that can carry infectious agents. Efforts to mitigate the spread of inhalable aerosols should emphasize proximate regions nearest the procedure, including personal protective equipment and the use of evacuation devices.

A scoping review of surgical masks and N95 filtering facepiece respirators: Learning from the past to guide the future of dentistry.

With the 2019 emergence of coronavirus disease 19 (colloquially called COVID-19) came renewed public concern about airborne and aerosolized virus transmission. Accompanying this concern were many conflicting dialogues about which forms of personal protective equipment best protect dental health care practitioners and their patients from viral exposure. In this comprehensive review we provide a thorough and critical assessment of face masks and face shields, some of the most frequently recommended personal safeguards against viral infection. We begin by describing the function and practicality of the most common mask types used in dentistry: procedural masks, surgical masks, and filtering respirator facemasks (also called N95s). This is followed by a critical assessment of mask use based on a review of published evidence in three key domains: the degree to which each mask type is shown to protect against airborne and aerosolized disease, the reported likelihood for non-compliance among mask users, and risk factors associated with both proper and improper mask use. We use this information to conclude our review with several practical, evidence-based recommendations for mask use in dental and dental educational clinics.