Infection Risk Prediction Model for COVID-19 Based on an Analysis of the Settlement of Particles Generated during Dental Procedures in Dental Clinics

Abstract

Background. The health emergency declaration owing to severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) has drawn attention toward nosocomial transmission. The transmission of the disease varies depending on the environmental conditions. Saliva is a recognized SARS-CoV-2 reservoir in infected individuals. Therefore, exposure to fluids during dental procedures leads to a high risk of contagion. Objective. This study aimed to develop an infection risk prediction model for COVID-19 based on an analysis of the settlement of the aerosolized particles generated during dental procedures. Materials and Methods. The settlement of aerosolized particles during dental aerosol-generating procedures (AGPs) performed on phantoms was evaluated using colored saliva. The gravity-deposited particles were registered using a filter paper within the perimeter of the phantom head, and the settled particles were recorded in standardized photographs. Digital images were processed to analyze the stained area. A logistic regression model was built with the variables ventilation, distance from the mouth, instrument used, area of the mouth treated, and location within the perimeter area. Results. The largest percentage of the areas stained by settled particles ranged from 1 to 5 µm. The maximum settlement range from the mouth of the phantom head was 320 cm, with a high-risk cutoff distance of 78 cm. Ventilation, distance, instrument used, area of the mouth being treated, and location within the perimeter showed association with the amount of settled particles. These variables were used for constructing a scale to determine the risk of exposure to settled particles in dentistry within an infection risk prediction model. Conclusion. The greatest risk of particle settlement occurs at a distance up to 78 cm from the phantom mouth, with inadequate ventilation, and when working with a high-speed handpiece. The majority of the settled particles generated during the AGPs presented stained areas ranging from 1 to 5 µm. This model was useful for predicting the risk of exposure to COVID-19 in dental practice.

A COVID-19 University-Based Dental Clinic Experience and Infection Control Protocol Modification for Safe Clinical Education

“…However, the literature is unclear regarding how far aerosols can spread. 24 25 26 27 The SARS-CoV-2 virus has been isolated from the saliva of infected patients, 28 including asymptomatic individuals, 29 but the potential viral load in the aerosols produced by dental procedures is unknown. Initial studies have also indicated that the virus could remain viable for hours in the aerosols and for days on surfaces.…”

Utilization of rapid antigen tests for screening SARS-CoV-2 prior to dental treatment

“…In the present study, the limited supply of antigen test kits during the fourth wave of the COVID-19 pandemic in Thailand led our team to take an efficacious strategy and practical approach to using such limited kits in this study. Those patients who are set up to receive aerosol-generating dental treatment have a higher chance of spreading viral particles in the dental treatment environment ( 21 , 22 ). Thus, the screening for SARS-CoV-2 infection was focused on these groups, despite the fact that all patients possess the risk of infection.…”