Association between periodontal disease and the risk of COVID-19 complications and mortality: A systematic review

Aim: The COVID-19 pandemic has strained the world's healthcare systems. Studies have identified how the COVID-19 infections are linked to several co-morbidities such as hypertension, diabetes, cardiovascular disease, renal and pulmonary disease. It is known that periodontal disease (PD) shares the same risk factors. Moreover, both diseases are characterized by an exaggerated immune response. The aim of the study was to investigate the available evidence of a potential association between PD and the risk of COVID-19 complications and mortality. Materials and Methods: MEDLINE/PubMed, EMBASE, Scopus, and ProQuest were searched. Studies that assess the association between PD and the risk of COVID-19 complications and mortality were eligible for inclusion. Two independent reviewers performed the selection of articles and data extraction. The New Castle Ottawa Scale was used to assess the quality of the selected studies, and the GRADE system was used to evaluate the level of confidence to support the conclusions. Results: Only two studies met the eligibility criteria. One study had a low risk of bias, whereas the other had a high risk of bias. Conclusion: The level of confidence in the available evidence is very low. A close association between periodontitis and the risk of COVID-19 complications and mortality can neither be supported nor refuted.