Oral manifestations of Covid-19-A literature review.

Initially, it was reported that coronavirus 2019 disease (Covid-19) affects respiratory, gastrointestinal and neurological systems, but the oral, olfactory and integumentary systems are also involved. This review discusses various oral manifestations of Covid-19 reported in the literature along with possible underlying mechanisms. The reported manifestations include taste impairment, oral mucosal changes (petechiae, ulcers, plaque-like lesions, reactivation of herpes simplex virus 1(HSV1), geographical tongue and desquamative gingivitis) and dry mouth. The prominent location for mucosal lesions are tongue, palate and labial mucosa. The exact pathogenesis of these oral symptoms is not known. Angiotensin-converting enzyme 2 (ACE2) cell receptors are expressed in abundance on oral mucosa allowing severe acute respiratory syndrome-coronavirus-2 (SARS-CoV-2) to infect them. Gustatory impairment along with olfactory changes is now listed as a symptom of Covid-19 by the World Health Organization, but further research is needed to confirm a link between reported additional oral symptoms and Covid-19. Dental professionals may encounter individuals with Covid-19 and be called upon to identify various oral manifestations of this disease.

Covid-19 and oral diseases: Crosstalk, synergy or association?

The coronavirus disease 2019 (Covid-19) is a viral infection caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) that clinically affects multiple organs of the human body. Cells in the oral cavity express viral entry receptor angiotensin-converting enzyme 2 that allows viral replication and may cause tissue inflammation and destruction. Recent studies have reported that Covid-19 patients present oral manifestations with multiple clinical aspects. In this review, we aim to summarise main signs and symptoms of Covid-19 in the oral cavity, its possible association with oral diseases, and the plausible underlying mechanisms of hyperinflammation reflecting crosstalk between Covid-19 and oral diseases. Ulcers, blisters, necrotising gingivitis, opportunistic coinfections, salivary gland alterations, white and erythematous plaques and gustatory dysfunction were the most reported clinical oral manifestations in patients with Covid-19. In general, the lesions appear concomitant with the loss of smell and taste. Multiple reports show evidences of necrotic/ulcerative gingiva, oral blisters and hypergrowth of opportunistic oral pathogens. SARS-CoV-2 exhibits tropism for endothelial cells and Covid-19-mediated endotheliitis can not only promote inflammation in oral tissues but can also facilitate virus spread. In addition, elevated levels of proinflammatory mediators in patients with Covid-19 and oral infectious disease can impair tissue homeostasis and cause delayed disease resolution. This suggests potential crosstalk of immune-mediated pathways underlying pathogenesis. Interestingly, few reports suggest recurrent herpetic lesions and higher bacterial growth in Covid-19 subjects, indicating SARS-CoV-2 and oral virus/bacteria interaction. Larger cohort studies comparing SARS-CoV-2 negative and positive subjects will reveal oral manifestation of the virus on oral health and its role in exacerbating oral infection.