K Chandrasekharan Nair1*, Pradeep Dathan2 and Bheemalingeswara Rao3
1Professor Emeritus, Department of Prosthodontics, Sri Sankara Dental College, Akathumuri, Varkala, Kerala State, India
2Professor and Head of the Department of Prosthodontics, Sri Sankara Dental College, Akathumuri, Varkala, Kerala State, India
3Professor, Department of Prosthodontics, Vishnu Dental College, Bhimavaram, AP, India Clinic
*Corresponding Author: K Chandrasekharan Nair, Professor Emeritus, Department of Prosthodontics, Sri Sankara Dental College, Akathumuri, Varkala, Kerala State, India.
Received: May 22, 2021; Published: June 12, 2021
Covid-19 pandemic has fallen on our society quite unexpectedly. Luckily the virus responsible for the disease was identified but the vaccines could be introduced after almost an year. By this time, the virus transformed into different strains, further complicating the treatment. Dental practice was affected the most because oral cavity harbours the virus in abundance. This overview provides a compilation of information present for the benefit of practising dentists and dental students.
Keywords: SARS-CoV-2; Disinfection Dental Clinics; Disinfecting Agents; PPE Kit; Precautions for COVID-19
Covid-19 is anxiously as well as curiously observed worldwide by scientists, professionals and common people. The origin of the disease is traced to live animals which were susceptible to coronavirus infection and sold in a food market in Wuhan (China). Animals acted as conduits for the virus to humans. The evolution of the disease was so rapid and has transformed into a public health crisis and spread exponentially throughout the world. At the end of 2019, coronavirus (SARS-CoV-2) with a genome length of 29,903 nucleotides was isolated by a Chinese researcher from a patient with pneumonia. Analysis of the genomic sequence of SARS-CoV-2 showed 88% identity with two bat-derived SARS-like coronavirus, indicating that mammals acted as the initial reservoir.
The COVID-19 recognised in India is part of the worldwide pandemic. On 30 January 2020, the first case of COVID-19 in India was reported, in Kerala, among three Indian medical students who had returned from Wuhan. India declared a lock down during the last week of March 2020. There was a rapid spread and the first wave of the disease dropped to below 15,000 new cases per day in January 2021. Subsequently a second wave began at a much larger scale than the first in March 2021.
Identifying the future risk, India launched its vaccination programme in January 2021. The British Oxford-AstraZeneca vaccine (Covishield), the Indian BBV152 (Covaxin) vaccine and the Russian Sputnik V vaccine were authorised by the Government of India for emergency use. Now India has nearly 20 million reported cases as on May 2021 .What is a ‘novel’ coronavirus?
The present pandemic is caused by Novel coronavirus (CoV) which is a new strain of coronavirus. The disease is named coronavirus disease 2019 (COVID-19) - ‘CO’ stands for corona, ‘VI’ for virus, and ‘D’ for disease (Figure 1). Covid - 19, Severe Acute Respiratory Syndrome (SARS) and some types of common cold are caused by the same family of viruses. Respiratory infections are transmitted through droplets having different sizes. A respiratory droplet gets its designation when the diameter is > 5 - 10 μm. When they are < 5 μm in diameter, they become droplet nuclei. In airborne transmission, microbes are enclosed in droplet nuclei, the diameter of which is < 5 μm and can remain in the air for longer duration. < 5 μm particles can travel distances greater than 1m. A report recently published in The Lancet has stated that ‘SARS-CoV-2, the virus that causes COVID-19, is an airborne pathogen’. The report has challenged the popular belief that coronavirus spreads only through smaller aerosols that remain suspended in the air or through fomites [2,3].
Figure 1: Corona virus - image from transmission electron microscope. Source: https://www.eurekalert.org/pub_releases/2020-01/c-ub-rdf011620.php.Symptoms
People with COVID-19 manifest a wide range of symptoms which may appear in 2 - 14 days after exposure to the virus. People with these symptoms may have COVID-19:
Senior citizens and people who suffer from serious medical conditions like heart or lung disease or diabetes seem to be on the higher side of risk because they may develop serious complications from COVID-19 illness .General procedures to be carried out to avoid the risk of infection
Figure 2: Right way of wearing mask. Source: https://news.llu.edu/health-wellness/which-type-of-face-mask-most-effectiveagainst-covid-19.
Figure 3: Different types of masks. Source: https://news.llu.edu/health-wellness/which-type-of-face-mask-most-effectiveagainst-covid-19.Common tests used for detecting Covid-19 infection RT-PCR test
The RT in the RT-PCR test stands for reverse transcription and it is an important step in the testing process because SARS-CoV-2 Virus is an RNA based virus. To detect presence of COVID-19 virus, scientists have to convert the RNA to DNA. This process is called ‘reverse transcription’. The Reverse Transcription of RNA to DNA is carried out because under laboratory conditions, only DNA can be copied or amplified, which is important for the detection of COVID-19 virus. As the number of new copies of viral DNA strands gathers in the sample, marker labels get attached to the DNA strands and then release a fluorescent dye. The computer of the testing machine tracks the quantity of fluorescence in the sample after each cycle and once a certain threshold is surpassed, the presence of the virus is confirmed.Antigen test
Antigen test and RT-PCR use almost the same method - that is using nasal fluid in a swab. Antigen test is considered as a rapid test in which the sample is mixed with a solution that unleashes specific viral proteins. The combined solution is then applied to a paper strip containing optimised antibody which binds with these proteins if they are present. The result is obtained as a band on the paper strip. The test doesn’t need a laboratory and can be completed in 30 minutes, but the speed very often limits the sensitivity. Although these tests are reliable when an individual has a high viral load. Antigen tests are prone to false-negative results if the virus in the body is less. However, it is not as expensive as RTPCR test.Rapid antibody test
Rapid Antibody Test looks for antibodies present in a patient’s blood samples. According to ICMR,’ these tests are mainly used for mass analysis and reporting’. Antibody testing determines whether a person had suffered from COVID-19 in the past and at present has antibodies against the virus. Antibody testing is also known as serology testing. A health care professional takes a blood sample, usually by a finger prick or by drawing blood from a vein in the arm. Then the sample is tested to determine whether one has developed antibodies against the virus. The immune system produces these antibodies (proteins) that are critical for fighting and clearing out the virus .Disease transmission and dental profession
Dental profession has a high potential to transmit Covid - 19 because of the following reasons:
Figure 4: Aerosol. Source: https://www.dw.com/en/dangersof-covid-19-aerosols-are-underestimated/a-54115303.Preventive care in dental clinics
While providing dental care standard precautions should be implemented which include health clearance, vaccination for healthcare workers, hand hygiene, personal protective equipment (PPE), instrument decontamination, safe sharps handling and sharps injury management, environmental cleaning and disinfection and clinical waste management.
Standard PPE consist of a surgical mask, face shield (usually with inferior opening) or protection goggles, gown, surgical cap, and gloves. Full or enhanced PPE include a surgical mask, face shield or protection goggles, disposable long-sleeved gown (waterproof), surgical cap and gloves in addition to respirators such as N95/FFP2 (filtering face pieces), respirators or powered air purifying respirators. FFP1 refers to the least filtering with an aerosol filtration of at least 80% for 0.3 μm particles and is mainly used as an environmental dust mask. FFP2 masks have a minimum of 94% filtration percentage and FFP3 masks have filtration percentage of 99%. N95 masks are so called because they are able to filter at least 95% of very small particles, including droplets containing the coronavirus (Figure 5 and 6). Sequence of putting on PPE is - wash hands - gown - mask - face shield - gloves. Sequence of removing PPE is - gloves - face shield - mask - gown - wash hands (Figure 7 and 8).
Figure 5: Face shield. Source: https://www.dezeen.com/2020/04/09/apple-coronavirus-face-shield/.
Figure 6: PPE kit. Source: https://www.indiamart.com/proddetail/ppe-kit-22252032912.html.
Figure 7: Sequence of putting on PPE.
Figure 8: Sequence of removing PPE. Source: https://www.dentalcare.com/en-us/professional-education/ce-courses/ce483/putting-on-and-safely-removing-ppe.
Masks are generally loose fitting and covers the nose and mouth. They are designed for one way protection, to capture bodily fluid leaving the wearer. Whereas respirators are tight fitting masks, designed to create a facial seal. Respirators (non valve) provide good two-way protection, by filtering both inflow and outflow of air.
During surgical procedures, it is recommended to apply preprocedural mouth rinses with chlorhexidine gluconate (CHX), povidone-iodine (PVP-I) or hydrogen peroxide (H2O2) and to put the patient in a supine position to avoid working in the breath way of the patient. Contaminated aerosols are filtered either by chairside high-volume evacuators (HVE) or more expensive HEPA (high efficiency particulate arrestor) filters. HVE filters reduce contamination by around 90% while HEPA filters can remove 99.7% of particles measuring 0.3 μm in diameter.
The possibility of Covid 19 transmission in dental clinics must be recognised and controlled efficiently, while dealing with patients with suspected or confirmed COVID-19 in order to prevent spreading primarily amongst health care workers. Preventive measures will also avoid cross-infection between patients especially in out-patient settings with poor ventilation and air filtering .Dental care providers are advised to:
Common sterilization protocols adopted regularly in the dental clinics are effective for the prevention of COVID-19 cross-infection. Commonly used autoclaves are effective because the virus cannot survive more than 30 minutes at temperatures above 560C. Sanitizing must be carried out on all surfaces of the dental unit, spittoon area and dentist and assistant’s stool. A spray of aqueous solution of hypochlorite at 1% or alcohol at 70% can be used and it can be left for at least 1 minute. Wipe the sprayed area with disposable clothes taking care not to go back to previously wiped areas. Water lines of the dental unit can be cleaned with a 0.5% hypochlorite solution, because residual water may be contaminated by viruses and bacteria. It is obligatory to carry out complete air change of the clinical space after each intervention because SARS-CoV-2 is able to remain suspended in aerosol for up to 3 hours. Continuous air exchange is possible through the use of air suction, filtration, UV lights, ozone generators and portable air cleaners with High-Efficiency Particulate Air (HEPA) filters. Windows with at least 2 square meter openings ensure efficient air exchange in 10 min for a 20 square meter room; they must be opened after each patient [10,11] (Figure 9).
Figure 9: Medical grade HEPA filters. Source: https://www.amazon.in/Medify-Medical-Filtration-Air-Purifier/dp/B08194ZQ4N.Dentists’ response
In a survey conducted by Rodrigues L., et al. dentists have made the following observations:
Due to the rapidly evolving nature of Covid-19 virus, it is germane for all oral health professionals to update themselves with new information. Precautionary measures are highly recommended until we understand the specific behaviour and infectious nature of the novel SARS-CoV-2 virus is understood in the light of the evidence collected from research which may eventually lead to the development of more effective vaccines and medications.
Though the pandemic has pushed both the professionals and public into a stressful situation, the profession has stood up to show grit in the fight against Covid 19. Many dentists have expanded their role beyond dentistry by offering voluntary service by virtue of their training and practical experience. Providing emergency service itself is a great opportunity to prove the relevance of the profession and no doubt we will pull through this crisis and emerge stronger than before.
Citation: K Chandrasekharan Nair., et al. “Know Covid-19 and Fight it - An Overview on the Pandemic”. Acta Scientific Dental Sciences 5.7 (2021): 68-74.
Copyright: © 2021 K Chandrasekharan Nair., et al. This is an open-access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.