Airborne Particle Control Methods in Dental Clinics

Abstract

Background and Objectives: The COVID-19 pandemic has highlighted the risk of airborne transmission of infections in health-care facilities such as dental clinics. In this experimental study, methods to control airborne particles in a simulated dental clinic setting were measured and compared using a low cost and convenient technique. Materials and Methods: Particles representing inhalable airborne particles were generated using smoke from incense sticks and their concentration measured by handheld particle sensors whereas using different engineering controls for the particle removal in dental clinic equivalent settings. Measurements were made at short (<3 ft) and intermediate (between 3 and 6 ft) distance from the source. The particle filtration through surgical masks and N95 masks was also studied. Results: Natural ventilation, by keeping windows open, can reduce intermediate range particles (removal of 4.7% of ambient particles/min). However, in closed facilities without natural ventilation, particle removal by air purifier combined with overhead fan or with high volume evacuators was found most suitable for intermediate range particles (25.9%/min) and for short range particles (27.6%/min), respectively. N95 masks were found to filter out 99.5% of the generated PM 2.5 particles. Conclusions: Potentially inhalable airborne particles can persist in the air of a dental clinic. The use of N95 masks and environmental controls is essential for the dental team's safety. The choice of an engineering control is governed by multiple factors explained in the study. Smoke particles generated by incense sticks and measurement by handheld particle sensors are low-cost methods to estimate the effectiveness of airborne particle controls.