Association Between Periodontitis and Coronavirus Disease (COVID-19) On A Sample of Adult Egyptian Patients: A Case Control Study

The coronavirus disease of 2019 (COVID-19) has become a new global issue since its outbreak in Wuhan, China, and has claimed millions of lives as a result. Despite having a low fatality rate of 2.1 percent (WHO), the disease has imposed an unacceptable cost on the world due to its high transmissibility and associated morbidity. The causal virus, severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), affects not only the respiratory system but also the cerebrovascular system and other important organs

Coronavirus is a highly contagious single-stranded RNA virus that causes mild to severe respiratory infections in humans and animals. SARS-CoV-2, a novel strand of the -coronavirus family, was discovered in Wuhan, China, in late 2019 which spread fast over the world, forcing WHO to designate the disease a global pandemic on March 11, 2020

The SARS-CoV-2 virus infects host cells by adhering to S-protein, a viral transmembrane spike (S) glycoprotein that clings to human cells by binding to angiotensin converting enzyme II (ACE2), a membrane protein that acts as a virus receptor (Walls et al., 2020). To enable viral fusion into target cells, host proteases such as TMPRSS2, cathepsin L, or proprotein convertase furin proteolytically break the S-protein after it binds to ACE2 . SARS-CoV-2 can also boost the expression of ACE2, making it easier for the virus to invade host cells.

Periodontal disease has been proved to be the most common oral condition of human population . It was widely spread in both the developed and developing countries. High prevalence of periodontal disease has been found in adolescents, adults, and older individuals. Smoking, poor oral hygiene, diabetes, medication, age, hereditary and stress were all considered to be the risk factors of periodontal diseases. Overall, they affected about 20-50% of the population around the globe

Gingivitis and Periodontitis are the most common forms of human periodontal diseases. Inflammation of the gingiva is called gingivitis. The gingiva includes all soft tissue surrounding the tooth coronal to the crest of alveolar bone and to a varying extent lateral to the bone, extending to the mucogingival junction. While, the periodontium includes cementum, periodontal ligament, alveolar bone and the gingiva. Periodontitis includes loss of attachment of periodontal tissues from the tooth together with net loss of alveolar bone height. That's why Gingivitis was found to be reversible, while regeneration after the periodontitis destruction was not predictably achievable . The prevalence of periodontitis has been reported by the World Health Organization (WHO) which showed a prevalence of severe periodontitis in around 8-10% of the Population.