The Pathogenesis of Oral Manifestations of COVID-19

Abstract

The COVID-19 pandemic which causes the SARS-CoV-2 opens the way to more than thousand serious pathological conditions of various organs and systems, including those in the oral cavity. Objective: To perform a systematic analysis of scientific articles and identify the main pathogenetic factors of COVID-19 affected the oral cavity. The search was performed on the PubMed and Google Scholar platforms using the following strategy: "COVID-19" + "Oral cavity". All articles presented in the open access, published before 01/04/2022 in the format of Case Reports, Clinical Studies, Clinical Trial Protocols, Clinical Trials, Multicentre Studies were analysed. 135 publications were included in the study after exclusion, 33.518 cases were analysed. Damage to the teeth, tongue, hard palate and oral mucosa, dysgeusia, xerostomia and ageusia are the most common manifestations of COVID-19 (17.137 reported cases). Suggested mechanisms of dysgeusia in patients with COVID-19 include direct cytotoxic effects of the virus on ACE-2-expressing receptors, angiotensin II imbalance, and peripheral taste and olfactory neurotropism. Salivary glands with increased expression of ACE-2 are also a target for COVID-19, they progress to xerostomia with the development of dysgeusia. The primary lesion of the oral mucosa was manifested in the form of multiple erythema and oedema (29 cases). Ulcers happened due to mucosal bite caused by muscle contraction, irritation by a foreign object during intubation were shown to lead to the development of neoplasms from benign fibroma to an aggressive form of cancer, especially against the background of corticosteroids (3 cases). Vitamin D deficiency lead to a decrease in the density of the maxillofacial bone and serves as a factor for tooth migration and periodontitis. The addition of a secondary infection is observed in connection with the suppression of the immune system, both by the virus itself and by medications. Pseudomembranous candidiasis (3 cases), recurrent herpes simplex (3 cases), saccharomyces cerevisiae (2 cases) and others have been registered. The analysis demonstrated that damage of the oral cavity can occur both because of the direct action of COVID-19, and indirectly, through psycho-emotional stress, antibacterial drugs, co-infection, neglect of hygiene measures, vitamin D and zinc deficiency.