Oral Health and COVID-19: A Two-Way Relationship

Dr. Kadeeja Shana K.V.


COVID-19 is an infectious disease caused by the SARS-CoV-2 coronavirus transmitted from person to person via droplets in the air or by contact with contaminated surfaces. It can have a significant impact on oral health, while oral health can influence a patient’s susceptibility to the virus as well.


Major symptoms of COVID-19 include fever, dry cough, and tiredness. Less common symptoms include loss of smell with or without loss of taste, sore throat, headache, conjunctivitis, and body pain. Severe symptoms include chest pain, breathing difficulties, and loss of speech or movement.

People most at risk of COVID-19 include older people and those with chronic systemic diseases such as cardiovascular diseases, pulmonary diseases, hypertension, diabetes, and cancer. As of October 1, there were 34,170,335 cases around the world, with 25,437,901 recoveries.

Bacterial flora and load in the oral cavity vary between people, depending on their oral care and associated chronic illnesses. For example, people with diabetes, hypertension, or cardiovascular diseases have altered biofilms. Their increased bacterial loads and COVID-19 infections can lead to super-infections. Hence, proper oral hygiene can reduce the severity of COVID-19.

Although this severity depends upon many host and viral factors, 80% of COVID-19 cases show mild symptoms, while 20% show severe symptoms due to already increased inflammatory markers and bacteria load due to dental problems. These cases also show increased neutrophil counts and decreased lymphocyte counts, suggesting bacterial super-infections.

The Impact of Salivary Flow

Saliva is a clear, tasteless, odorless, and mildly alkaline viscous and complex fluid that is composed mainly of water and inorganic and organic substances. Components include enzymes, proteins, immunoglobulins, electrolytes, and mucosal glycoprotiens.

In addition to functions like lubrication, digestion, cleansing, water level balance, and buffering, saliva is the first line of defense against infection as well. Proteins like lysozyme, mucins, cystatins, lactoferrin, cathelicidin, peroxidase, salivary agglutinins, and alpha and beta defensins have antiviral properties. Some of these proteins may reduce the replication of SARS-CoV-2.

A considerable decrease in salivary flow could then reduce the antiviral activity that saliva provides, making hyposalivation a significant risk factor for COVID-19. Certain drugs like anti-hypertensive medications, anti-cholinergic medications, and NSAIDs used in chronic conditions like hypertension and cardiovascular diseases cause hyposalivation, increasing COVID-19 risks.

Impact of COVID-19 Treatment on Oral Health

Even after patients have recovered from COVID-19, they may experience oral health issues such as ulcers, xerostomia, stomatitis, and oral thrush. Some of these issues may be side effects from medication that they took during the COVID-19 infection.

Patients with severe COVID-19 symptoms may receive interferon-beta, chloroquine, hydroxychloroquine, ot remdesivir. The use of lopinavir and ritonavir may decrease viral load, severity, and adverse clinical outcomes as well and even potentially reduce death rates in patients with SARS. Interferon alpha and beta also can reduce the severity of COVID-19 by reducing respiratory illness. Broad-spectrum antibiotics also are used in severely ill COVID-19 patients.

Since there is little data on COVID-19’s relationship with oral health, it is believed that the normal side effects that these medications present persist in patients even after they have recovered from COVID-19 infection.

Corticosteroids are not advised for use during COVID-19 treatment, so conditions such as pemphigoid, phemphigus, and lichen planus that require their continuous administration may be exacerbated.

On the contrary, tocilizumab (atlizumab), which targets the IL-6 receptor in treating autoimmune diseases such as rheumatoid arthritis, cytokine release syndrome, and systemic juvenile idiopathic arthritis, was recently approved for treating severe COVID-19 infections associated with lung damage due to high levels of IL-6.

Severely ill and hospitalized patients also may have deteriorated oral health because lifesaving procedures including intubation, external ventilation, and tracheostomies are more important at the time. Also, it has been reported that SARS-CoV-2 has some neurotropic and mucotropic abilities that can affect salivary gland function, the oral mucosa, and taste and smell.

Thus, acute and severe COVID-19 infection and its pharmacological therapy can cause xerostomia and opportunistic fungal infections due to hyposalivation, oral ulcers, and gum disease as a result of reduced immunity. Hence, good oral care is advised after treatment in a hospitalized environment and moving to the home environment.


The overall relationship between COVID-19 and oral health seems to be bilateral, though there is a lack of research on it so far. Experimental treatment protocols for curing the infection seem to be beneficial, though they exhibit certain side effects. The development of a vaccine would be the best approach to improve COVID-19 rates and its impact on oral health alike.

Dr. Shana is a dental surgeon who graduated from the Kerala University of Health Sciences. She is an avid reader and aspiring writer about new dental trends. She can be reached at kadeejashanakv@gmail.com.

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