This study aimed to investigate the association between periodontitis and COVID-19 complications, considering the exacerbated inflammatory response observed in both conditions. Materials and Methods: A case-control study was conducted using national electronic health records from February to July 2020. Cases were defined as COVID-19 patients who experienced complications, while controls were COVID-19 patients who were discharged without major complications. Periodontal conditions were assessed using dental radiographs obtained from the same database. Logistic regression models were employed to analyze the associations between periodontitis and COVID-19 complications, adjusting for demographic, medical, and behavioral factors. Results: A total of 1000 patients were included in the study. After adjusting for potential confounders, periodontitis was found to be significantly associated with COVID-19 complications, including death, ICU admission, and the need for assisted ventilation. Conclusion: This study concluded that periodontitis was linked to a higher risk of ICU admission, the need for assisted ventilation, and death among COVID-19 patients. Additionally, elevated levels of biomarkers associated with worse disease outcomes were observed in patients with periodontitis. These findings highlight the potential impact of periodontal health on the severity and prognosis of COVID-19, emphasizing the need for integrated oral and systemic healthcare approaches in managing the disease.