Dental Asia May/June 2020

can bind to the receptors of the host to
facilitate viral entry into target cells. The
virus protein can be dissolved by detergent
and alcohol disinfectant and cannot tolerate
hot temperature over 25°C 2 .
The novel β-coronavirus was named by
WHO as COVID-2019. It can cause severe
and even fatal pneumonia in human. The
transmission routes of COVID-2019 can be
by direct person-to-person transmission via
coughing, sneezing, saliva, and inhalation of
discharged droplet. Contact transmission is
also common to oral, nasal, and eye mucous
membranes after touching virus since it
can survive on metal and plastic surfaces
for hours 2 .
Patients suffering from COVID-19 will
experience mild to moderate respiratory
illness. They may recover without special
treatment. However, older people with
chronic medical problems such as diabetes,
Symptoms
cancer and cardiovascular disease will
develop serious pulmonary fibrosis and
respiratory failure. The best way to prevent
infection is to understand its cause and
spread, and intercept. Social distancing,
regular hands washing with alcohol rub
and not touching one’s face are strongly
recommended by CDC.
In dental settings
Face-to-face close communication in dental
surgeries is unavoidable and the environment
is exposed to saliva, blood, and other body
fluids via aerosol generated by dental
instrumentations. Dental profession workers
are encountering high risk; therefore, a
strict guideline is urgently needed to protect
dentists, staff and patients. It was confirmed
that those without symptoms can spread
the virus 4,5 .
The typical clinical symptoms of COVID-19
pneumonia patients are fever, dry cough,
coarse breathing sounds,
and myalgia or fatigue with
abnormal ground-glass chest
X-ray. The less common
symptoms are sputum
production, loss of sense of
smell, headache, haemoptysis,
diarrhoea and lymphopenia. In
severe cases, acute respiratory
distress, RNAaemia and acute
cardiac injury lead to death 8,9 .
The patient sputum show
positive real-time polymerase
chain reaction that confirmed
COVID-19 infection 10 .
Laboratory studies show
leucocytes 2.91x10^9 cells/L
of which 70% are neutrophils.
High erythrocytes count
sedimentation rate and D-dimer
are also observed 12 . While there
is no specific antiviral drugs
or vaccine for humans, broadspectrum
antiviral drugs like
nucleoside analogues and
HIV-protease inhibitors could
attenuate virus infection until specific
antiviral drugs become available 11 .
Being in close proximity to one another is
unavoidable in dental settings
Spread by airborne virus
Aerosol transmission of COVID-2019 is of
the most concern in dental settings since
it is difficult to minimise the production of
aerosol and droplets mixed with saliva and
blood during operative procedures. Virus
can stay airborne for a while in droplet
particles and aerosols before they settle
on surfaces or enter the respiratory tract.
Dentists and their staff are constantly
in contact directly with human fluids,
patient exudates, and contaminated dental
instruments and surfaces.
An infected person who coughs can propel
his droplets and aerosols a distance, causing
infection if the virus comes into contact
with another person’s eyes, nose, or mouth.
This can happen even during conversation
without a mask. An effective infection control
system is needed to prevent the spread
through this media 6,7 .
Spread from contaminated surfaces
COVID-19 can survive on metal, glass, and
plastic surfaces for hours. It is a potential
source of coronavirus transmission since
contaminated surfaces in surgery are
MAY / JUNE 2020 DENTAL ASIA 45