The Oral-Systemic Link: COVID-19 and Oral Health

We know there is a link between the mouth and the rest of the body. The same cytokines active in COVID‑19, such as TNFα, IL-1β, IL-6, and IL-8, to name a few, are also involved with the inflammatory process and development of periodontitis. Periodontitis has long been recognized as having its pathophysiology established in a cytokine response.87 The connection between COVID‑19 and periodontal disease through their cytokine connection is an additional rationale for recommending maintenance of oral hygiene and continued provision of dental in the COVID era. Patients with periodontitis had a higher risk of ICU admission, need for assisted ventilation and death of COVID‑19 patients, and with increased blood levels of biomarkers linked to worse disease outcomes, according to a new study. This may be explained by the fact that COVID‑19 is associated with an exacerbated inflammatory response that can result in fatal outcomes, and systemic inflammation is also a main characteristic of periodontitis.88

A new study theorizes that the mouth and nose are key entry points for SARS‑CoV‑2 into the bloodstream, not the airway, and that at-home selfcare measures such as toothbrushing and interdental cleaning could reduce the risk of developing severe lung disease as a result of coronavirus.89 The hypothesis of the authors was based on a number of findings. Computerized tomography (CT) scans of COVID‑19 patients have shown COVID‑19 lung disease is not a pneumonia in the conventional sense, but it is similar to inflammation of the pulmonary vessels at the base of the lungs. They also stated that there is a viral reservoir in the oral cavity and saliva, and that there could be a possibility for translocation of the virus from saliva to the gingival sulcus/periodontal pocket. The authors further hypothesize that the route taken by the virus from saliva in the mouth, via the gingival tissues, into the blood vessels of the neck, and chest, through the heart, and to the lung blood vessels, is a possibility.89

Figure 1. The COVID‑19 Pathway: A Hypothetical Model for the Oral-vascular-pulmonary Route of Infection.89
Illustrated diagram of the COVID-19 pathway for the oral-vascular-pulmonary route of infection (hypothetical model)

We also know that dental procedures were initially thought to pose a high risk of viral transmission because the instruments and handpieces that are used often produce aerosols, which could potentially contain high numbers of SARS‑CoV‑2 virions, copies of the virus causing COVID‑19. In a recent study, researchers stated that by understanding how to reduce the amount of aerosol generated in the first place, their suggestions could help dentists’ practice more and help patients get the treatment they need.90

There are numerous resources available for Oral Health Professionals: