As of February 2021, COVID-19 has not yet converged globally. Careful countermeasures are required for protecting infection of COVID-19 at dental clinics. Virus particles in saliva are likely to spread outside during dental treatment. Dental staffs must use a variety of personal protective equipment (PPE). In addition, the frequency of using dental aerosol suction devices in the dental office has increased dramatically, and the sound environment in the clinic has changed after taking the measures against COVID-19. In this study, we will report the measurement results of the changes in the sound environment during dental treatment that were perceived by dental healthcare professionals and patients.