Oral health conditions and COVID-19: A systematic review and meta-analysis of the current evidence

Background: The coronavirus disease 2019 (COVID-19) pandemic has highlighted the importance of understanding the underlying conditions that lead to COVID-19. Oral health has systemic implications in the maintenance of a healthy state. This study aimed to summarize evidence on the prevalence of oral health conditions in participants with COVID-19 and assess the associations between oral health conditions and COVID-19 related outcomes. Methods: Article searches were conducted in five databases and the gray literature from December 1, 2019 to March 1, 2021. Studies that reported oral health conditions for participants with COVID-19 and/or examined associations between oral health and COVID-19 were included. Results: We identified 15 articles that encompassed 5,377 participants with COVID-19 from 10 countries. Dry mouth was the most common oral health condition reported (41.0%), followed by oral lesions (38.8%), orofacial pain (18.3%), and periodontal symptoms (11.7%). Based on the pooled odds ratios (ORs), periodontal symptoms were not associated with COVID-19 positivity (OR = 1.1; 95% confidence intervals [CI], 0.73-1.65) or mortality (OR = 2.71; 95% CI, 0.64-11.51), but were associated with COVID-19 severity (OR = 3.18; 95% CI, 1.81-5.58). Conclusions: Oral health conditions are common in participants with COVID-19 and should be considered in both the onset and progression of this disease. Knowledge in this area is still limited, and the quality of the data extracted was low. Further longitudinal studies are needed to ascertain whether oral health conditions are a consequence of infection with SARS-CoV-2 or whether they predate infection and are risk factors for COVID-19.