● Studies show that 30-56% of patients with COVID-19 may present with xerostomia due to the disease itself or to the medications used to treat the symptoms
● SARS-CoV-2 affects different parts of the oral cavity, including the salivary glands, and, together with other factors, produces an increased risk of xerostomia

Barcelona, 3rd  June 2021. Several scientific studies have shown that the prevalence of xerostomia, or dry mouth, increases up to 30-56% in patients with COVID-19, while, in the general population, without counting the effects of the pandemic, it can vary between 20 and 40%.  

Xerostomia, or the subjective sensation of dry mouth, is generally associated with a decrease or absence of saliva or changes in its composition. This decrease in saliva production can negatively affect patients’ health and quality of life.

The hypotheses formulated by various investigators suggest that in the case of patients who have been affected by COVID-19, dry mouth might occur as a direct consequence of the coronavirus, which affects the salivary glands, causing a decrease in saliva production. This involvement could be caused by the expression in the salivary glands of ACE-2 receptors, which the SARS-CoV-2 coronavirus uses to infect human cells.

At times, this direct effect of the virus could be aggravated by side effects from medications used to treat the symptoms produced by the virus or by the continued use of a mask, which promotes mouth breathing in lieu of nasal breathing, resulting in increased dryness of the oral cavity.

The onset of xerostomia may vary depending on age and general health status and may be caused by a number of medications, tobacco smoking, drinking alcohol, ageing, stress, anxiety, some diseases, and as several studies show, as a consequence of COVID- 19. The main warning symptoms of dry mouth, or xerostomia, are:

• Feeling of dry and/or pasty mouth
• Burning tongue
• Bad breath
• Distorted sense of taste
• Persistent thirst
• Difficulty chewing, swallowing, or speaking
• Dry lips

“A lack of moisture in the oral cavity can produce various clinical manifestations in the mouth and cause a decrease in the quality of life of patients suffering from xerostomia,” points out Ernesto de la Puente, DENTAID Research Center Medical Science Liaison. “It may cause multiple effects, ranging from dryness, redness or irritation, inflammation of the oral mucosa (stomatitis), bad breath (halitosis), fissured lips and tongue or an increased risk of oral infection, among others”, adds de la Puente.

Saliva is necessary for the proper functioning of the oral cavity, as it serves to clean and protect the mouth, allows us to perceive taste, regulates pH, aids in digestion and facilitates speech. Besides the previously described discomforts, a decrease in normal saliva secretion can cause the accumulation of harmful bacteria responsible for the appearance of cavities, gum disease, bad breath or recurrent oral infections, etc.

Since xerostomia is a disorder that may result from other systemic diseases, its management may involve multiple healthcare professionals, including dentists and/or medical specialists of each specific disease.

Dr Carmen Jódar, a primary care physician, tells how xerostomia is a widespread problem, affecting patients other than just those affected by COVID-19. “It is a disorder that affects the general population, and more so now with the use of masks, which induces decreased saliva flow and dries out the mouth a lot,” she says. “The time of use of the mask is proportional to the dryness of the mouth”, concludes the doctor.

In most cases, dry mouth can be treated by recovering or stimulating salivary secretion. One possible solution might be to recommend the use of products that help hydrate the oral cavity and that promote natural saliva production. In cases of irreversible xerostomia, the solution involves maximising the hydration of the oral cavity.