The most common routes of transmission of coronavirus disease 2019 are droplet and contact infections. During dental treatment, several instruments and procedures used generate droplets of saliva and blood, such as during the extraction of an impacted third molar (M3). Surgical masks are often used during tooth extraction. However, the surface structures of surgical masks against droplets are not fully understood. Therefore, we analyzed the droplets that adhered to the surgical masks during impacted M3 extraction using electron microscopy. The surgical mask was divided into three layers and observed using electron microscopy. The outer and inner layers had a similar mesh-like structure, whereas the middle layer had a denser three-dimensional structure. Droplets ranging from 20-100 µm in size, generated during the extraction, adhered to the fibers of the outer layer of the mask. Fewer droplets adhered to the middle layer than to the outer layer. Droplets did not reach the inner layer. In conclusion, we suggest that a surgical mask can prevent droplet infection when performing impacted M3 extraction. This study is expected to contribute to the study of infection control strategies during dental treatments in the future.
Keywords: coronavirus disease 2019; droplet; electron microscope; surgical mask; tooth extraction.