OBJECTIVE: To retrospectively review the impact of the outbreak of coronavirus disease 2019 (COVID-19) on services in the oral emergency room. MATERIALS AND METHODS: A statistical analysis of epidemiological characteristics and the patients' diagnoses and treatments in the Emergency Department of Peking University Hospital of Stomatology during the outbreak of COVID-19 in 2020 compared with those in 2019 in Beijing, China. RESULTS: There were fewer total visits in 2020 than in 2019 (P = 0.001), and the proportions of patients who were children, adolescents and elderly people were lower in 2020 than in 2019 (P < 0.001). The proportions of patients with acute toothache and infections were higher in 2020 than in 2019, and the proportions of patients with maxillofacial trauma and non-emergencies were lower in 2020 than in 2019 (P < 0.001). Drug treatment for acute pulpitis was used more often in 2020 than in 2019, and endodontic treatment and examination consultations were less common in 2020 than in 2019 (P = 0.022). CONCLUSIONS: The outbreak of COVID-19 affected the patient population and structure of disease types and oral services in the emergency room. The number of visits to the oral emergency room and the proportions of the patients who were children, adolescents and elderly people were reduced, meanwhile the percentage of emergency cases, except trauma, and conservative treatments increased during the outbreak of COVID-19.