Periodontal Disease Markers among Patients with Long COVID: A Case-control Study

Long-COVID affects approximately 32-87% of COVID-19 patients and causes persistent symptoms that last more than 4 weeks after initial infection. Long COVID is associated with a notable cytokine triad, namely IL-1β, IL-6, and TNF-α. Periodontal disease also involves proinflammatory cytokines production, including IL-1β, IL-6, and TNF-α. Consequently, long-COVID, which has an impact on proinflammatory cytokine release, could have an impact on periodontal status.

This study aims to see whether long COVID affects periodontal status severity based on proinflammatory cytokines levels involved in both diseases, namely IL-1β, IL-6, and TNF-α.

Patients were divided into periodontitis or gingivitis patients and then were further divided into two groups, previous COVID-19 patients and non-COVID-19 patients (controls). Gingival sulcus fluids were obtained from each patient using paper points inserted in the patients’ sulcus, and ELISA tests were carried out to measure IL-1β, IL-6, and TNF-α levels.

Levene Test indicated that there were no substantial differences between IL-1β, IL-6, and TNF-α levels (0.057, 0.135, and 0.341, respectively) in COVID-19 patients with gingivitis in comparison to the control group with gingivitis, with average IL-1β, IL-6 and TNF-α levels seen higher in the control group compared to COVID-19 patients. There were also no substantial differences between IL-1β, IL-6, and TNF-α levels (1.00, 0.567, and 0.666, respectively) between COVID-19 patients with periodontitis and the control group with periodontitis. Although higher levels of IL-6 and TNF-α were found higher in COVID-19 patients in comparison to the control group.

Levels of IL-6 and TNF-α in periodontitis patients with long COVID were higher than controls. But despite that, higher IL-1β, IL-6, and TNF-α levels were not found in long COVID subjects with gingivitis, as well as IL-β levels in the periodontitis group. Further studies with more subjects are needed to determine the connection between these two diseases further.

Clinical Trial Registration No: The clinical trial registration of this research is 014/S3/KEPK/FKG/10/2021.