The present study sought to evaluate the impact of quarantine resulting from the coronavirus disease 2019 (COVID-19) pandemic on dental appointments and patients' positions and concerns regarding their ongoing dental treatment. Patients from private dental clinics answered an online questionnaire anonymously regarding their treatment, availability and willingness to attend dental appointments, and concerns about contamination. Descriptive statistics of the responses were performed with percentages and responses were compared between sexes, regions, and other aspects using the chi-squared test. Five hundred ninety-five patients (412 females and 183 males; mean age: 38.21 years) answered the questionnaire. Most patients reported they were receiving dental treatment (orthodontics) and would attend to a dental appointment; meanwhile, those patients not receiving treatment would not attend or would visit only in the case of an emergency. Males reported to be calmer than females, who were more anxious and afraid; as such, males reported more willing to go a dental appointment while, in general, females were not worried about how quarantine could affect dental treatment. Patients actively undergoing treatment and orthodontic patients were more concerned about a delay in treatment. There was a significant association between feelings about the COVID-19 pandemic and the level of willingness to attend a dental appointment. The quarantine recommended due to the COVID-19 pandemic was shown to have an impact on dental appointments and the anxiety levels of patients, since there was a significant association between patients' feelings and their willingness to attend a dental appointment. Overall, patients undergoing dental treatment and orthodontics were more willing to attend an appointment and were more concerned about an increase in treatment duration.