Oral and Systemic Health - is There a “new” Link With COVID-19?

Abstract Body: During the last decades, the association between periodontitis and different systemic conditions has been established, based on epidemiological studies, preclinical studies to assess biological plausibility and interventional studies. Today, the associations have been clearly defined with a variety of conditions, highlighting endocrine conditions (including diabetes mellitus), cardiovascular diseases, adverse pregnancy outcomes, respiratory infections, rheumatoid arthritis, Alzheimer`s disease, among others. The bases for the association include the frequent bacteremia observed in periodontitis subjects, together with higher levels of systemic inflammation. The relevant role of the mouth in the transmission of SARS-CoV-2 and the severity of COVID-19 has recently raised the hypothesis of a possible association between periodontitis and the severity of COVID-19. Different studies have already explored the association of periodontitis and oral hygiene and different respiratory diseases (including chronic obstructive pulmonary disease, asthma, community-acquired pneumonia, obstructive apnea), suggesting a rationale to also explore the association between periodontitis and COVID-19. Although the number of published studies is still limited, and the quality of the evidence is also improvable, the initial evidence is suggesting that periodontitis may be associated with a more severe COVID-19 and even with higher risk of dead due to COVID-19. The implications of these findings need to be cautiously interpreted, since they may be valid not just for SARS-CoV-2 and COVID-19, but also for other viral and bacterial infections in the upper and lower respiratory tract, and may further emphasize the importance of oral hygiene and periodontal health in systemic health.