Major clinical findings of the oral hygiene relationship and increase in the predisposition to COVID-19: a systematic review

Introduction: The disease caused by the novel coronavirus 2019 (COVID-19) is caused by a newly identified virus Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2). The risk of nosocomial transmission is a reality that requires the development of guidelines by the dental community to reduce the chances of infection by the new coronavirus. In particular, poor oral hygiene, opportunistic infections, stress, immunosuppression, vasculitis, and a hyperinflammatory response secondary to COVID-19 are the most important predisposing factors for the appearance of oral lesions in patients with COVID-19. Objective: It was to highlight the main clinical studies on the relationship between hygiene and care in the oral cavity to reduce the chances of contamination with COVID-19, as well as to observe the interrelation between poor oral hygiene and the increased risk of this contamination. Methods: The rules of the Systematic Review-PRISMA Platform were followed. The research was carried out from March 2022 to May 2022 and developed based on Scopus, PubMed, Science Direct, Scielo, and Google Scholar. The quality of the studies was based on the GRADE instrument and the risk of bias was analyzed according to the Cochrane instrument. Results and Conclusion: A total of 124 articles were found. In total, 42 articles were fully evaluated and 10 were included and evaluated in this study. Considering the Cochrane tool for risk of bias, the overall assessment resulted in 42 studies that were excluded with a high risk of bias (studies with small sample size). Also, 30 studies were excluded because they did not meet the GRADE. COVID-19 affects oral health most likely in patients with serious illness, which may be due to the disease itself, immune response, and lack of motivation for personal hygiene measures. Furthermore, the results indicated that gargling with mouthwashes composed of unique antiseptic agents may play a minor role in potentially reducing transmission rates, and therefore these findings are of utmost importance when considering alternative COVID-19 prevention strategies