Objectives: COVID-19 has introduced an unexpected level of uncertainty to every aspect of our lives, and loss of access to care has become a major problem. This study has two main objectives, one being to characterize the frequency of insurance approvals and denials for Medicaid patients seeking orthodontic treatment in Pennsylvania before and during COVID-19, and the second being to identify differences in appointment keeping behavior between Medicaid and non-Medicaid orthodontic patients during those timelines.Methods: 634 Medicaid and 304 non-Medicaid patients were screened at Temple University Kornberg School of Dentistry, Department of Orthodontics from July 2018 to March 2019 (pre-COVID-19) and July 2020 to March 2021 (during COVID-19). Each patient’s Insurance Provider, Salzman Index Score (SEI), the insurance eligibility decision (approval/denial), and history of all attended and failed appointments for both Medicaid and non-Medicaid patients during pre-COVID-19 and during COVID-19 timelines were collected. Results: For the first objective, there were 270 approvals (96%) and 10 denials (4%) pre-COVID-19 and there were 270 approvals (76%) and 84 denials (24%) during COVID-19. There was a significant difference in the rate of insurance approvals and denials pre-and during COVID-19, with a p-value of <0.001. For the second objective, Medicaid patients attended 7221 (81%) and failed to attend 1746 (19%) of 8967 appointments and non-Medicaid patients attended 3419 (85%) and failed to attend 589 (19%) of 4008 appointments pre-COVID-19. During COVID-19, Medicaid patients attended 7115 (81%) and failed 1637 (19%) of 8752 appointments and non-Medicaid patients attended 3171 (87%) and failed 484 (13%) of 3655 appointments. The results showed a significant difference in the number of failed appointments between Medicaid and non-Medicaid groups (p <0.001). At a significance level of 0.01, there were no significant interactions between the number of failed and attended appointments for Medicaid nor non-Medicaid patients pre- and during COVID-19 (p =0.149, p =0.065). Conclusions: These findings suggest that the number of insurance approvals and denials during COVID-19 decreased and increased, respectively. Furthermore, these data show that Medicaid patients have a higher rate of appointment failures than non-Medicaid patients pre- and during COVID-19. / Oral Biology