LAUSR

Dear Editor, In the course of the last months, coronavirus disease 2019 (COVID-19) has been affecting populations throughout the world and causing serious public health problems, as the virus (severe acute respiratory syndrome coronavirus 2; SARS-CoV-2) responsible for this disease causes severe respiratory disease and has a high potential for transmission. According to data announced on July 28, 2020 by the World Health Organization (WHO), COVID-19 has infected more than 16,341,920 million people and caused about 650,805 deaths worldwide. This exceeds the number of deaths that the WHO estimates annually to be caused by viral influenza (250,000 to 500,000 deaths). Currently, with the improvement of the COVID-19 situation in countries where the number of cases has stabilized or decreased, such as most European and Western Pacific countries and some Asian countries (e.g., New Zealand and Taiwan), social distancing measures have been relaxed and there has consequently been a gradual return to common activities, such as in-person classes and clinical practice in dental schools. Nonetheless, it is important to highlight that as long as there is no effective treatment or vaccine to fight infection by SARS-CoV-2, new waves of transmission will be possible, regardless of the current situation in different countries. The main form of transmission of COVID-19 is through direct or indirect contact with mucous secretions, respiratory droplets, and aerosols from infected patients. Thus, dental schools’ clinics represent high-risk environments for the transmission of SARS-CoV-2 among patients, undergraduate and graduate students, staff, and professors, since the production of aerosols by ultrasonic devices and high-speed dental handpieces is inevitable during dental care, and professionals are in close proximity to patients’ oral cavity. When performing dental procedures with a high-speed handpiece or ultrasonic device, the friction between the tooth and the fast-rotating bur could create excessive heat. Thus, to avoid heat gain, there is a universal consensus that a water coolant should be used while performing dental procedures, such as tooth preparation, oral prophylaxis, and oral surgery. The water coolant, however, has the potential to generate aerosols. When combined with fluids in the oral cavity, such as blood and saliva, bioaerosols are created. These bioaerosols are commonly contaminated with bacteria, fungi, and viruses, and can float in the air for a considerable period of time and be inhaled by dentists and other patients. Therefore, the implementation of more rigid infection control measures is mandatory to significantly reduce these risks. Most individuals infected by SARS-CoV-2 are asymptomatic or have mild symptoms similar to those of other common viral infections (20-68% of all infections). However, the viral load and transmission rate do not seem to be related to the presence or severity of symptoms. Therefore, asymptomatic patients or those with mild symptoms have the same potential for transmission as symptomatic patients. Hence, the return to clinical activities in dental schools may represent an imminent risk for community transmission if stricter biosafety measures are not adopted, regardless of the dental specialty. Oral radiology centers at dental schools are less susceptible to aerosol production than centers specializing in other fields of dentistry, such as oral surgery, endodontics, restorative dentistry, and periodontics. However, this does not mean that the procedures performed in radiology clinics are not potential sources of COVID-19 transmission among patients, students, and professors. In addition to Oral radiology practice in dental schools during the COVID-19 pandemic: What will be the new normal?