AEROSOL AND DENTISTRY IN COVID ERA

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ABSTRACT

Aerosol and splatter play a significant role in

transmission of infection in a dental set up, which is of

great concern for the dentist and the patient. Major source

of aerosol in a dental set up is from ultrasonic scalers and

rotary instrument which are of primary importance for

performing regular dental procedures. Since the

aerosolized particles behave in a ballistic manner and can

stay suspended in air for a long period of time, the

probability of surface contamination and transmission of

infection through contact of these contaminated surfaces

within dental clinic is extremely high. Presently our

anxiety due to possible aerosol contamination has

increased multiple folds due to the COVID-19 pandemic

crisis. Hence knowing the properties and composition of

the aerosol, would give an insight into reducing the

microbial load in the aerosol being generated during the

regular dental procedures.

KEYWORDS:

COVID, Aerosol procedure, Airborne

infection

JIDAM/Chennai/Volume:7/Issue:3/Pages 91 - 95 / July- Sep 2020

Address for Correspondence:

Dr. Lekha A, MDS,

Lecturer, Department of Periodontology,

Sri Ramachandra Faculty of Dental

Sciences,

Sri Ramachandra Institute of Higher

Education and Research, Chennai-600

116, Tamilnadu, India.

Email id: drlekha@sriramachandra.edu.in

Received

: 15.08.2020

Accepted

: 16.09.2020

Published

: 27.09.2020

REVIEW ARTICLE

Dr. Lekha A, Dr. S.K. Balaji

Department of Periodontology, Sri Ramachandra Faculty of Dental Sciences,

Sri Ramachandra Institute of Higher Education and Research, Chennai, Tamilnadu, India.

DOI:1.37841/jidam_2020_V7_I3_03

JIDAM/Chennai/Volume:7/Issue:3/Pages 91 - 95 / July- Sep 2020

Lekha et al : Dentist- Know Thy Aerosol

INTRODUCTION:

The pioneering work done by Micik and

colleagues on aerobiology, have defined aerosols as

those airborne

particles less than 50 μm in diameter

and if the particles size was larger than 50 μm in

diameter, it was called as splatter

1-5

. These particles

were found to behave in a ballistic manner.

The consensus has been that the major spread

of infection in dental clinic is airborne infection due

to aerosol that is generated during dental procedures

and its potential to enter respiratory passages

6,7

These aerosols generated during the dental

procedure pose a risk factor for disease transmission

among the dentist, the dental team and the patient.

The potential source for spread of infection in a dental

office can happen either through direct contact with

body fluids of an infected patient or through indirect

contact with contaminated environmental surfaces or

due to airborne particles from the infected patient.

An aerosol cloud is generated during

various dental procedures performed using rotary

instruments, ultrasonic scalers, air-water syringe

and air polishing instruments. The ubiquitous cloud

of aerosol comprises of combination of materials

originating from the within the oral cavity and from

the Dental Unit Waterline (DUWL). The source of

infectious contaminants present in the aerosol can be

either from the operative site, saliva and respiratory

sources. Literature evidence shows that the greatest

amount of airborne contamination is generated by

the ultrasonic scaler, followed by the air-driven

high-speed hand piece, the air polisher and air-water

syringe

5,9-14

COMPOSITION OF DENTAL AEROSOLS:

The oral fluids are grossly contaminated

with bacteria and viruses from supragingival plaque

and also from deep periodontal pockets. Oral cavity

being a part of the oro-nasal pharynx complex,

harbours microorganisms from the nose, throat and

respiratory tract. Dental procedures which generate

aerosol, potentially cause airborne contamination

with organisms from some or all of these sources.

The composition of dental aerosol varies

with operative site and each patient. Hence

it is extremely difficult to analyse the aerosol

qualitatively and quantitatively. The dental aerosol

supposedly comprises of components of saliva,

blood, nasopharyngeal secretions, plaque, tooth

fragments and dental material used for treatment.

Several studies have been done to assess the number

of bacteria present and also analysed the blood

components present in the dental aerosol

16,17

Tuberculosis is considered as an occupational

hazard in dentistry, because the most potential threat

that can be present in dental aerosol is Mycobacterium

tuberculosis

18,19

. Several other pathogenic organisms

like the SARS virus, influenza virus, herpes virus,

pathogenic Streptococci and Staphylococci are found

in the nasopharyngeal secretions and saliva, thereby

increasing the risk of spread of infectious disease

conditions through dental aerosol

DROPLETS AND AEROSOLS –

ITS SIGNIFICANCE IN DISEASE

TRANSMISSION

Studies have proven that highly virulent

pathogens like severe acute respiratory syndrome-

coronavirus (SARS-CoV) present in aerosol can

travel distances greater than six feet

. Surfaces

contaminated with nosocomial pathogens are

potential route of transmission for several infections

Human corona virus including SARS-CoV

and MERS-CoV can undergo onward transmission

because of their ability to persist on a surface for

a few days, and also due to their ability to remain

suspended in human secretions

21,22

. Acquisition of

pathogen from contaminated surfaces and if when

transferred to the eyes, nose, or mouth can result in

transmission of infection

JIDAM/Chennai/Volume:7/Issue:3/Pages 91 - 95 / July- Sep 2020

Lekha et al : Dentist- Know Thy Aerosol

Disease transmission that occurs through Airborne route via Droplets or Aerosols

DISEASE

METHOD OF TRANSMISSION

Pneumonic Plague Transmits from one patient to another by inhalation of the causative

bacteria, without contact with the usual insect vector (flea)

Tuberculosis

Transmits via Droplet nuclei which is expelled from the patient while
coughing

Influenza

Transmission requires direct contact with the patient but can also be
associated with coughing

Legionnaires’
Disease

Aerosolization and transmission of Legionella pneumophila can occur
through air conditioning systems and hot tub spas

Severe Acute
Respiratory
Syndrome

Spread of disease through direct contact and aerosolized droplets

NOVEL CORONA VIRUS:

A pneumonia outbreak with unknown

etiology occurred in Wuhan, China by the end of

2019 and this disease condition was named corona

virus disease 2019 (COVID-19). An increase in

the number of cases reported worldwide prompted

the World Health Organization (WHO) to declare

the COVID-19 crisis a “Public Health Emergency

of International Concern”. On 11 March 2020,

WHO declared the Novel Coronavirus Disease

(COVID-19) outbreak to be a pandemic. The possible

routes of this virus transmission are mainly through

direct contact and droplet transmission. An exposure

to high concentration of aerosol in a relatively

closed environment can be considered as one of the

potential route of transmission of COVID-19. Since

routine dental procedures like scaling generate high

concentration of aerosol, the possibility of corona

virus transmission in dental setting is relatively high.

Hence knowledge on disease transmission through

aerosol and its implication in dentistry is very

essential, specifically during this pandemic crisis.

METHODS OF

REDUCING AIRBORNE

CONTAMINATION:

There is no single step preventive measure

available to completely minimize the risk of infection

to dental personnel and the patients. Hence it is

advisable to follow a multiple layer of preventive

measures because a single layer of defense can

partially reduce the risk of cross infection. To reduce

the potential danger from dental aerosol, layering of

infection control procedures needs to be followed

Thus, the dental team can adopt the following layers

of preventive procedures that is necessary to reduce

the dental aerosols

. Personal protection barriers such

as gloves, masks and protective eyewear will serve

as a first layer of defense in protecting the dentist

and the assistants within the operatory. Routine use

of an antiseptic preprocedural mouthwash such as

chlorhexidine will serve as a second layer of defense

by minimizing the bacterial load in the oral cavity and

use of a high-volume evacuator either by an assistant

or attached to the instrument will reduce the quantity

of aerosol being generated. Installation of devices

such as HEPA filters, can serve as an additional layer of

defense in reducing the aerosol contamination within

the operating area. The appropriate work practice

precautions are achieved by using rubber dams and

HVEs, and hence should be followed during dental

procedures

Centre of Disease Control has suggested

“Interim Infection Prevention and Control Guidance

for Dental Settings during the Coronavirus Disease

2019 Pandemic”

. Since the virus has been shown to

persist in aerosol for hours and on some surfaces for

few days under laboratory conditions, the potential

risk of transmission of virus in a dental setting is

high. But there are currently no data available to

JIDAM/Chennai/Volume:7/Issue:3/Pages 91 - 95 / July- Sep 2020

Lekha et al : Dentist- Know Thy Aerosol

assess the risk of Coronavirus disease transmission

during dental practice. Hence CDC has developed a

framework for healthcare personnel and healthcare

systems for delivery of non-emergent care during the

COVID-19 pandemic. Thorough assessment of the

patient should be carried out prior to providing any

dental treatment. It is important to weigh the risk:

benefit ratio for both the patient and the Dental Health

Care Provider (DHCP) in deferring the treatment.

Availability of adequate Personal Protective

Equipment (PPE) and supplies is mandatory to

support both the patient and DHCP

. Implementation

of tele-dentistry and triage protocols prior to dental

treatment should be followed. CDC have also

recommended Infection Prevention and Control

(IPC) practices when providing dental healthcare for

a patient with suspected or confirmed SARS-CoV-2

infection and for routine dental healthcare delivery

during the pandemic

CONCLUSION:

Considering the high risk of exposure

to serious disease conditions through aerosol

contamination among dental clinics, it is mandatory to

adapt to various protocols which has been laid down

to reduce the quantity of aerosol generated during

the routine dental procedures and also minimize the

risk of exposure to dental health care provider and

patients by following strict infection prevention and

control measures.

FINANCIAL SUPPORT AND SPONSORSHIP:

Nil

CONFLICTS OF INTEREST:

There are no conflicts of interest.

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