Coronavirus disease 2019(1) SARS-CoV-2(1) Coronavirus disease 2019 (COVID-19)(1) Coronavirus disease 2019 (COVID-19).(1) diagnosis and treatment process(1) health care personnel(1) Ventilation.(1) recurrent aphthous ulcers(1) New coronavirus(1) Infection prevention and control(1) Airborne transmission(1) stress response(1) nosocomial infection prevention and control (1) Personal protective equipment(1) population risk classification.(1) disease prevention during dental care(1) cheilitis.(1) Oral and maxillofacial surgery(1) dentistry(1) aerosol(1) oral lichen planus(1) protection.(1)