ACE2 and infection: Different functions, including speaking, coughing, and sneezing, are involved in virus transmission.53 To infect the tissues and organs, SARS-CoV-2 displays mechanisms to invade different cell types, and its entry occurs mainly through the ACE2 and TMPRSS2 receptors.24 Therefore, cells that bear such receptors are susceptible to infection by SARS-CoV-2.64 Several studies have demonstrated the presence of ACE2 and TMPRSS2 receptors in oral tissues.45 In 2020, Xu et al61 reported a high expression of the ACE2 receptor in epithelial cells of the tongue.