SARS-CoV-2 Did Not Spread Through the Dental Clinic in the Pandemic Period in Japan

Background: Dental professionals were thought to have the most significant risk of coronavirus infection at pandemic period. Since the first Corona-Virus Disease-2019 (COVID-19) patient was detected in Japan in January 2020, Japan has faced several waves of Severe Acute Respiratory Syndrome Corona Virus 2 (SARS-CoV-2) infections. However, no cluster of SARS-CoV-2 infections associated with dental practice had been reported in Japan. In this study, we aimed to investigate the actual status of SARS-CoV-2 infection at pandemic period through antibody testing for dental professionals. We further investigated the saliva and oral management-related aerosol to estimate the risk of virus transmission during dental practice. Methods: SARS-CoV-2 antibody titer in the blood of dental professionals and their families was determined during the pre-vaccinated period of the SARS-CoV-2 wave to see the history of infection in Japan. Viral loads in saliva and in the aerosol generated during oral management of COVID-19 patients were detected by RT-qPCR. Results: The antibody testing of dental health care providers during the early phases of the pandemic period in Japan revealed low antibody positivity, which supported the low incidence of infection clusters among dental clinics. The aerosol generated during dental practice may contain trace levels of SARS-CoV-2, indicating the risk of transmission through dental practice is limited. Therefore, SARS-CoV-2 did not spread through dental clinics. Conclusions: Very few SARS-CoV-2 infections were observed in dental professionals who took appropriate infection control measures at the early period of the pandemic. Dental practice using standard precautions seems to be sufficient to prevent SARS-CoV-2 infections.