Introduction
The novel human corona virus disease COVID-19, a pandemic disease caused by Severe Acute Respiratory Syndrome corona virus 2 (SARS- CoV-2) is a severe respiratory disease associated with high mortality and morbidity. This disease from Wuhan of China is exponentially spreading all over the world exhibiting severe impact on routine lifestyle, economy and most importantly health. This is the fifth documented pandemic subsequent to 1918 Spanish flu (H1N1), 1957 Asian flu (H2N2), 1968 Hong Kong flu (H3N2) and 2009 Pandemic flu (H1N1). Its origin has been traced to a province called Hubei in the Wuhan city of China.1 In India, the first case of this COVID-19 was reported from Kerala among 3 medical students who have returned from Wuhan on January 30, 2020. 2 The novel Corona virus outbreak was declared as a global pandemic by WHO on March 11, 2020.
Oral cavity is considered a mirror of systemic health. Multiple oral manifestations have been and are being reported in patients with COVID-19. Few manifestations appear secondary to the COVID-19 disease and some as a result of the treatment regimen used to contain the disease. Common oral manifestations include ageusia, anosmia, hypo salivation, ulcers, herpes ulcers, fungal infections like mucormycosis, submandibular salivary gland enlargement, cervical lymph node enlargement etc. This article is a comprehensive review on COVID-19 disease, its oral manifestations and the standard operating protocols to be followed by dentists.3
The spiked virus
The novel corona virus resembles a crown with multiple spikes on it and so it is named as ‘Corona’ which is derived from a Latin word meaning ‘crown’. The spiked structure of the virus can be appreciated in an electron microscope. 4 It is an enveloped virus that has a single stranded RNA. It belongs to the genera- beta corona virus and is 26-32 kilobase in size. This virus is also of zoonotic origin similar to other corona virus. The China horse shoe type of bats is believed to be the zoonotic species of origin for SARS-CoV-2.5 The virus enters the host cell either by endosomal membrane fusion or plasma membrane fusion. There is a glycoprotein in the viral called as the S protein. This protein helps in binding and facilitate the entry of these organism into the host cell. 6 The S protein binds to receptor ACE2 (angiotensin converting enzyme 2) of the host cell. This binding is primed by TMPRSS2 (transmembrane protease serine 2).7
The respiratory droplet from the cough and sneeze of the infected patients is a transmitting medium among humans. This transmission is higher when the exposure area to respiratory droplet is within 6 feet distance. The transmission can also be from the hands touching the settled droplets from the sneeze or cough and when the same hands are then taken to mouth and nose.8 Transmission of infection via faecal-oral route transmission have also been evident in recent studies.9 Patients are infectious until symptoms subside. Even after the recovery, patients can be contagious. These viruses can even stay as droplets on surfaces and survive, if the surrounding atmosphere favours them. But this can be eliminated with disinfectants such as sodium hypochlorite.10 Although multiple ways of transmission has been documented, the most significant and appropriate way of transmission is by directly getting exposed to the infected individuals.
Clinical Features of COVID-19
The clinical features this COVID-19 varies among each and every individual. Manifestations range from asymptomatic to severe acute respiratory distress, at times leading to death. Symptoms include fever, sore throat, cough, myalgia, fatigue, head ache and in few cases difficulty in breathing. In a study by Chen et al, 11 fever was a manifesting sign in 82 of 99 COVID-19 positive cases. Cough was present in almost 81 of 99 cases, followed by shortness of breath in 31 cases. More than one symptom as manifestation was reported in 90% of cases. Fever, cough and shortness of breath were seen as a triad in almost 15% of cases. Inflammatory cytokines including IL2(interleukin-2), IL7(interleukin-7), IL10(interleukin-10), G-CSF (granulocyte colony stimulating factor), IP10(inducible protein 10), MCP1(monocyte chemo attractant protein 1), MIP1A (macrophage inflammatory protein 1), and TNFα (tumor necrosis factor α )were seen increased. Acute Respiratory Distress Syndrome was seen in 17% of cases, Acute renal injury in 3% and Acute respiratory injury in 8% of cases. Septic shock was seen in 4% of cases and Ventilator-associated pneumonia in 1% of cases.
Chest radiograph and Computed Tomography are gold standard diagnostic technique in evaluating the stage of disease as they detect the condition of lungs affected with pneumonia. A study by Attaway et al, revealed that about 15-30% of the COVID-19 patients develop acute respiratory distress syndrome. Diffuse alveolar damage with high thrombus burden in pulmonary capillary is seen in autopsy of patients who succumb to COVID-19. 12 Initially the disease was seen affecting and causing death in elderly and immuno-compromised patients, but gradually cases were among younger patients as well. A severe pneumonia with multiple organ dysfunction was observed in a case first reported in China.13 The first case of neonate was also reported from China and was mild. 14
Oral Manifestations of COVID-19
COVID-19 presents with an array of oral manifestations which appear during the course of the disease, few lesions manifesting post disease as a secondary infection or as a result of the treatment for the disease.
Most frequently reported oral manifestations include ageusia, anosmia, hyposalivation, ulcers in various parts of oral cavity including tongue, glandular enlargement, cervical lymph node enlargement, angular chelitis, periodontitis, aphthous and herpetic ulcers. Ageusia(loss of taste) and Anosmia(loss of smell) are the most common oral symptoms. 15, 16
Mucormycosis or black fungal infection is a potentially dangerous mycotic infection reported in COVID-19 patients. Uncontrolled diabetes mellitus, hyperglycemia, immune suppression and secondary infection, corticosteroid therapy are factors contributing to Mucormycosis as a co-infection in COVID-10 patients. 17 Another Mycotic disease that has been reported in COVID-19 patients is the invasive yeast infections caused by candida species. Prolonged ICU stays, central venous catheters and broad spectrum antibiotic use are the key factors leading to onset of invasive yeast infections in COVID-19 patients. 18
Several other non-specific lesion such as mucositis have been reported in some cases. Exanthema, enanthema, macules, papules and plaques on tongue, lip, palate, etc have been reported. Vasculitis, thrombotic vasculopathy, mucosal hypersensitivity, secondary to COVID-19 might be a cause for the mucositis associated with COVID-19. 19
Table 1
Procedure to wear a personal protective equipment (PPE) - Centre for disease control andprevention 20
Table 2
Procedure for safe removal of ppe kit - centre for disease control and prevention 20
Guidelines for Dental Practice in this Pandemic
COVID-19 is transmitted through respiratory droplets. Dentists are more prone to exposure to the respiratory droplets as their occupation involves working in oro-facial region. Particularly aerosol inducing procedures such as scaling, root canal treatment etc transmits the disease and the probability of getting infected is high. Hence, safety measures are essential to prevent the dentist from contracting the disease as well as prevent the patient from transmitting the disease. In India, Dental Council of India has formulated a standard to be followed by every Dentist in his practice. 21
Patient Management
Patient is first encouraged towards a telephonic consultation followed by scheduling of appointment. Initial screening is done by asking 3 important questions like whether the patient has come in contact with any COVID-19 patient or suspected patient, their travel history and finally any symptoms for Covid-19 present. Positive response for any of the three question should be considered and in such cases the appointment should be delayed for at least 14days and the patient is advised for a mandatory quarantine. The patient is also advised to consult his general physician. 22
On patient arrival to the clinic, the patient temperature is measured with an infrared thermometer or camera with infrared sensors. Any patient presenting with fever or any of the COVID-19 symptoms should be given appointment after 14days. As per Centre for Disease Control (CDC) guidelines, the suspected patients should be seated 6ft away from the healthy patients. Their environment should be adequately ventilated. 23 Pharmacological management with antibiotics and analgesics can be advised to these patients. Patient screening and management should be followed as in Figure 1. 10 Patients are classified into elective, urgent and emergency care for their treatment and then further treatment is planned. For elective care, appointment is delayed for 2 weeks. For urgent care, pharmacological management is first advised and then a close follow up with telephone or video call is done. In case of emergency, care a negative pressure room or airborne infection isolation room is preferred to perform any procedure. 24
Patient should be given 0.2% povidone iodine mouth rinse or 0.5-1% hydrogen peroxide mouth rinse as these have proven to reduce load of Corona virus in saliva.10, 25 Personal care has to be taken by the dentist to prevent the disease transmission. Double masking, use of face shield and personal protective equipment, frequent sanitization of hands can help prevent transmission to the dentist.23
Use of Personal Protective Equipments
There are certain guidelines propsed by Centre for Disease Control and prevention for wearing and safe removing of Personal Protective Equipment kits. The type of PPE used will vary based on the level of precautions required, such as standard and contact, droplet or airborne infection isolation precautions. The procedure for putting on [Table 1] and removing PPE[Table 2] should be tailored to the type of PPE.
Safe Removal of Personal Protective Equipment (PPE)
There are a variety of ways to safely remove PPE without contaminating our clothing, skin, or mucous membranes with potentially infectious materials. Remove all PPE before exiting the patient room except a respirator, if worn. Remove the respirator after leaving the patient room and closing the door. A proper sequence must be followed in removing the PPE kit (Table 2).
Conclusion
The COVID-19 pandemic is a global crisis due to its propensity to replicate and spread rapidly. It is indeed extremely challenging to control because of emergence of new mutated versions of the virus. To avoid exposure to dentists and also prevent the dental office from serving as area for transmission standard operating protocols by Dental Council of India and from Centres for Disease Control and prevention should be strictly implemented and followed. To conclude, proper oral hygiene to reduce severity of COVID-19, appropriate use corticosteroids and maintenance of blood sugar at optimum level helps prevent severe oral infections that can cause mortality.
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