Modeling of the Transmission of Coronaviruses, Measles Virus, Influenza Virus, Mycobacterium tuberculosis, and Legionella pneumophila in Dental Clinics

Abstract

<jats:p> Dental health care workers are in close contact to their patients and are therefore at higher risk for contracting airborne infectious diseases. The transmission rates of airborne pathogens from patient to dental health care workers are unknown. With the outbreaks of infectious diseases, such as seasonal influenza, occasional outbreaks of measles and tuberculosis, and the current pandemic of the coronavirus disease COVID-19, it is important to estimate the risks for dental health care workers. Therefore, the transmission probability of these airborne infectious diseases was estimated via mathematical modeling. The transmission probability was modeled for Mycobacterium tuberculosis, Legionella pneumophila, measles virus, influenza virus, and coronaviruses per a modified version of the Wells-Riley equation. This equation incorporated the indoor air quality by using carbon dioxide as a proxy and added the respiratory protection rate from medical face masks and N95 respirators. Scenario-specific analyses, uncertainty analyses, and sensitivity analyses were run to produce probability rates. A high transmission probability was characterized by high patient infectiousness, the absence of respiratory protection, and poor indoor air quality. The highest transmission probabilities were estimated for measles virus (100%), coronaviruses (99.4%), influenza virus (89.4%), and M. tuberculosis (84.0%). The low-risk scenario leads to transmission probabilities of 4.5% for measles virus and 0% for the other pathogens. From the sensitivity analysis, it shows that the transmission probability is strongly driven by indoor air quality, followed by patient infectiousness, and the least by respiratory protection from medical face mask use. Airborne infection transmission of pathogens such as measles virus and coronaviruses is likely to occur in the dental practice. The risk magnitude, however, is highly dependent on specific conditions in each dental clinic. Improved indoor air quality by ventilation, which reduces carbon dioxide, is the most important factor that will either strongly increase or decrease the probability of the transmission of a pathogen. </jats:p>

Perioral Aerosol Sequestration Suction Device Effectively Reduces Biological Cross-Contamination in Dental Procedures

“…We observed a significant decrease, around 98.4%, in whole dental environment contamination with the use of OBF. Our results corroborate the risk of biological cross-contamination by droplet and splatter described by Watanabe et al 4 and Zemouri et al 7,12 in operator's and patient's protective gear, thus demonstrating the utility of bioluminescence to assess the reduction of droplet and splatter spreading by using OBF. The limitation of our study is that bioluminescence, despite being able to identify living microorganisms, such as bacteria, dinoflagellates, and fungi, does not detect the presence of viruses.…”

“…15 This can be achieved either at a macro level increasing ventilation or at the source of contamination by applying an aerosol suction device, like the OBF, which was initially developed for astronauts in space. In the absence of gravity, particles of saliva or blood containing pathogens are released into the environment 16,17 as also reported in patients in isolated missions 17 both probably due to reduced ventilation, as suggested by Zemouri et al, 7 which studied the analogous situation in dental clinics due to the indoor air quality. The perioral suction device named Oral BioFilter (OBF) consists in an ergonomic lip retractor that supports an extraoral suction device which connects to the dental chair's high-volume evacuator (HVE) suction system.…”

Investigation of potential aerosol transmission and infectivity of SARS-CoV-2 through central ventilation systems

“…Dai and Zhao [ 26 ] estimate the infective dose for SARS-CoV-2 to be 14–48 quanta/h. Zemouri et al [ 27 ], estimated intermediate risk for SARS-CoV-1 to be ∼29 quanta/h (with a range of 11.4–295.5 quanta/h for low to high risk, respectively). Miller et al [ 28 ], estimated an infectious dose of 970 quanta/h for the superspreading Skagit Valley choir practice.…”

An estimation of airborne SARS-CoV-2 infection transmission risk in New York City nail salons

“…It is acknowledged that there are still gaps in the literature regarding the transmission of this novel human coronavirus. The value of the quanta generation rate ( q ) has varied among a few studies ( Buonanno et al, 2020 ; Dai and Zhao, 2020 ; Zemouri et al, 2020 ) and needs to be studied further. The value of q used in this study was derived from a novel approach based on the viral load emitted in saliva ( Buonanno et al, 2020 ).…”