The COVID-19 pandemic has significantly impacted healthcare systems worldwide, including dental care. This study aimed to investigate the effects of the pandemic on the management of medication-related osteonecrosis of the jaw (MRONJ). Abnormal blood glucose levels may contribute to the development of MRONJ and act as an important risk factor. This retrospective study included 217 patients with MRONJ. The patients were divided into two groups: the pre-COVID-19 group (16 March 2018 to 16 March 2020; 75 patients; 46 females and 29 males; average age, 74.5 years) and the post-COVID-19 group (1 June 2022 to 1 June 2024; 142 patients; 91 females and 51 males; average age, 69.6 years). Data pertaining to demographic characteristics, length of hospital stay, glucose levels, location of lesions, and underlying diseases were collected. The average length of hospital stays was 4 and 5 days in the pre- and post-COVID-19 groups, respectively. The average fasting glucose levels were 5.5 and 5.9 mmol/L in the pre- and post-COVID-19 groups, respectively. Localization patterns shifted, with a higher incidence in the maxilla in the post-COVID-19 group. These findings suggest a significant increase in MRONJ cases and changes in clinical outcomes due to the pandemic. The increase in the number of patients treated after the pandemic highlights the importance of ongoing vigilance and adaptation in preventing MRONJ, with a particular focus on risk factors.