INTRODUCTION: This retrospective study aimed to quantify the impact of coronavirus disease 2019 (COVID-19) on the orthodontic appointment and make an analysis of orthodontic emergencies (OEs) that occurred during the pandemic. METHODS: A total of 628 patients were randomly sampled from 3489 subjects who were undergoing active orthodontic treatment with fixed appliances, and the medical records were reviewed. OE occurrence was analyzed from 617 patients who had explicit return-visit records after the COVID-19 outbreak. Wilcoxon signed rank tests, chi-square tests, and a binary logistic regression were performed. RESULTS: The return-visit of 98.6% of the patients was delayed significantly with an increase over 8.98 +/- 4.76 weeks (P <0.001). In general, 32.3% of the patients suffered from various OEs while waiting for their first return-visit, and bracket or band debonding was the most frequently reported category. Most OEs did not receive timely treatments because of the lockdown. The incidence was nearly 2 times higher than that of the normal appointment times. No correlation was found between OE occurrence and different demographic and clinical characteristics of patients. The therapeutic progress of patients, especially those in stage 3, was postponed because of the occurrence of OEs. CONCLUSIONS: Regardless of the limitations, our study suggested that it is highly possible that the COVID-19 pandemic has delayed appointments of fixed orthodontic patients. OEs did bother a minority of patients and could not be settled in time during the lockdown, which had a negative impact on the near-term treatment progress and should have been prevented. Further studies are required to investigate the long-dated influence of COVID-19 on orthodontic practices.