Keywords COVID-19 - Public Health Dentistry - Infection control, dental - Primary prevention
Introduction
The coronavirus (CoVs) are RNA viruses characterized by the presence of 80 to 160
nM crown-shaped peplomers with positive polarity. The other feature is its high mutation
rate that constantly develops transcription errors, as well as RNA replicase (RNA
dependent RNA Polymerase, RdRP) jumps. These features make CoVs zoonotic pathogens
with a wide range of clinical features from asymptomatic to severe infections, most
of which acute respiratory syndrome (SARS), requiring hospitalization in the intensive
care unit.[1 ]
[2 ]
First cases of SARS from CoVs have been seen in China, state of Guangdong, in the
2002 and 2003. About 10 years later, CoVs-related Middle East respiratory syndrome
(MERS) has been observed.[3 ] In our time, novel coronavirus has been detected on December 12, 2019 in China,
the Wuhan State of the Hubei Province, which caused global pandemic.[4 ] The CoVs are common in many different animal species, including camels, cattle,
cats, and bats. Wild animal trade in the Huanan Seafoods Market has been known as
the origin area.[5 ] At first, it was an unknown pneumonia case with fever and other coronaviruses-related
symptoms. Nevertheless, about 1 month later (January 7, 2020), Chinese authorities
announced that a new CoV was isolated,[5 ] then named COVID-19 (World Health Organization [WHO]). The outbreak of the new coronavirus
has been declared a pandemic global emergency by the WHO (March 11, 2020), and global
quarantine by CoV spread as the main factors to control the disease. At the time of
writing this manuscript, 22,705,645 cases of COVID-19 have been reported, including
794,104 deaths (https://www.ecdc.europa.eu/en/geographical-distribution-2019-ncov-cases ). There is an important difference between affected countries mostly because different
case definitions and testing strategies were applied. Moreover, people suspected of
having COVID-19 may be higher than the official total, since some mild and asymptomatic
cases are not tested and counted; as a consequence, the number of infected people
increases every day. The lockdown contributed to contain the spread of the virus.
Nevertheless, the number of new COVID-19 cases has risen sharply over the past 2 weeks.
So the question is what happens next? For this reason, to prevent CoV spread and the
consequent “second wave,” all the people should be considered infected and general
rules must to be strictly maintained, including safe and healthful social and working
conditions. According to the occupational risk pyramid for COVID-19 published by the
Occupational Safety and Health Administration (OSHA, osha.gov/covid-19), dentist is
classified as a job with very high exposure risk to known or suspected sources of
COVID-19. First, dentists need intimate contacts (within 3 feet) with people, and
then dental health care workers performed every day during dental work, aerosol-generating
and blood-borne procedures from potentially infected patients. The human transmission
of CoV occurs with close contact with one another through the respiratory droplets
produced by infected people, mostly when person coughs and sneezes. These droplets
can settle down in the mouth or nasal mucosa of people who are nearby (within about
3 feet) and/or potentially inhabited into the lungs breathing with.[6 ]
[7 ] On March 15, 2020, the New York Times published an article entitled “The Workers
Who Face the Greatest Coronavirus Risk.” For this reason, primary concern of dental
health care workers is the own infection prevention and control measures against the
new coronavirus, adopting proper and certified personal protective equipment (PPE).
However, for the same principle, the second concern is that respiratory droplets can
land onto the nearly surfaces. Currently, it remains unclear but very possible that
a person can be infected by COVID-19 by touching an infected surface or object and
then touching their mouth, nose, or possibly eyes.[7 ]
[8 ]
[9 ] While it should be easy to protect itself from infection, this scenario expose at
high risk of cross infection and subsequently spread of the infection within patients,
practitioner, and person in contact with all of them, such us parents and family.[8 ]
[9 ]
Dentistry is essential health care because of its role in evaluating, diagnosing,
preventing, or treating oral diseases, which can affect systemic health. Nevertheless,
because of the infection risks associated with aerosol-generated procedures, dentists
around the world have been essentially closed since late March 2020. During this period,
there was limited access to emergency dental care. Dental services are now slowly
and tentatively beginning to reopen, although there is considerable variation in the
guidance being issued on the safety procedures required. As governments mandates lift
and dentists reopen practices, this narrative review does not want to be a standard
of care or official regulation, and it does not create legal obligations. This manuscript
presents recommendations of mandatory and safety dental health care standards, intended
to help dentists in providing a safe and healthful workplace during pandemic, that
means live together with the COVID-19. The main object of this narrative review was
to evaluate and discuss the actual available information regarding COVID-19 and dental
practice to answer to these questions: how can dental health care workers protect
itself from CoV infection? And how can dentist reduce the risks of cross infection
in their clinics?
Patients and Methods
The present narrative review was conducted following current data and previously published
practical guidelines on COVID-19. The focused question was: COVID-19 coexistence in
the daily practice. A literature search of available manuscripts was performed to
identify relevant studies according to the focused question. The PubMed database of
the U.S. National Library of Medicine and relevant websites ([Supplementary Material ] [available in online version]) have been consulted. A critical analysis of the available
literature was performed by the authors and grouped in five sections.
Measures to Reduce Surfaces Contamination before Dental Treatments
Prevention plays an important role in protection from the disease and to reduce risk
of cross infection.[10 ]
[11 ] Of course, dental health care workers must consider all the potential infected people.
Nevertheless, typically, like most respiratory viruses, people are thought to be most
contagious when they are most symptomatic. Phone coronavirus triage is mandatory to
evaluate risk level of our patients. The survey must be done the day of the visit
and it begins by asking patients if they are currently experiencing:
Severe cough, shortness of breath, fever, or other concerning symptoms
Contact with confirmed case(s) of COVID-19
Quarantine or isolation due to suspect or conclamate COVID-19
Vulnerable patients (>60 years and/or patient with concomitant pathologies) should
postpone the therapy if possible
Any other known reasons that may expose patients to be a high risk of spread of the
infection
Before the sch eduled appointment, the secretary must contact the patient asking to
answer the questionnaire and reminding her/him to follow some general rules. Vice
versa, the secretary must reassure the patient that the dental clinic is a safe place
where all the recommendations to contain infection are strictly adhered to.
To arrive in the dental clinic alone or with maximum one companion if needed (i.e.,
child treatment), avoiding assembly of people
To leave in the waiting room potentially infected objects (jacket, bag, phone, etc.)
To accurately hands cleaning at the arrival or to wear gloves
To wear the face mask up to dental chair
To rinse the mouth for 3 minutes with alcohol-based mouthwash before treatment
Further considerations will regard the availability of a rapid serological blood-based
test that should be able to identify whether people have been exposed to COVID-19.
Measures to Reduce Degree of Contamination during Dental Treatments
It should be better to postpone all the “not necessary therapies” to “better days.”
The authors really understand that most of the dental procedure should be the matter
of urgency even if not symptomatic or paucisymptomatic. The American Dental Association
classified dental emergency in urgent and not urgent therapies (https://www.ada.org/en ). For the latter, not urgent therapies are initial or periodic oral examinations,
recall visits, routine dental cleaning and preventive therapies, orthodontic procedures,
extraction restorative dentistry of asymptomatic teeth, and aesthetic dental procedures.
To define and limit the risk areas, the authors proposed to identify three areas of
risk ([Fig. 1 ]). The dental unit represents a “high-risk zone” (or red zone) due to surfaces contamination
and generation of aerosol during most of the dental treatments. This area has a radius
of approximately 3 feet from the patient’s mouth. Outside this area, all the operative
room, including adjacent working areas (such as dental laboratory, sterilization room,
dental office, patient toilette, etc.) must be considered a “medium-risk zone” (orange
zone) due to possible contamination of the surfaces. These areas could be contaminated
directly by touching the surfaces with gloves during the dental treatments by the
main operator, dental assistant, patient, or indirectly, bringing infected material.
All the rest of the dental clinics must be considered a “low-risk zone” (yellow zone)
because it is not possible to exclude possible contamination. Red zone required high
level of protection and attention.
Fig. 1 Identification of risk zones. Red zone includes dental chair and main operators.
This is the higher risk zone due to air (aerosol) and surface contamination. Orange
zone is a medium risk due to high possibility or surface contamination. Yellow zone
represents all the dental clinic where possible surfaces contamination could not be
completely excluded.
Use rubber dam when possible or other specific tools to improve dental isolation (e.g.,
specially designed mouth retractors) and to reduce aerosol generation (e.g., specially
designed suction evacuator).
Encourage use of speed-increasing handpiece instead of turbine handpiece
Encourage manual scaling instead of ultrasonic teeth cleaning during professional
dental hygiene procedure
Avoid dental treatments with airflow
Encourage use of digital impression with intraoral scanner to avoid use of impression
materials, reducing risk of cross infection.[12 ] Furthermore, to avoid dental laboratory delivery of potentially infected materials,
even if decontamination procedures are performed according to the actual rules.
Self-contained water system should be used instead of current water to supply water
to handpieces (including external piezo ultrasonic scalers) and syringes. This allows
for adding sterile hypochlorous acid for sanitizing the water. Hypochlorous acid is
safe and approved by the Food and Drug Administration. Contact times of 1 minute or
greater are typically sufficient to achieve a thorough kill including viruses. The
concentration of sanitizer in the wash water must not exceed 200 ppm hypochlorite.
The patient must be rinsed with potable water following the chlorine use.
Apply a team-based chain of control that means organizing a logical workplace zones
and operative sequences. At least two dental assistants should assist the main operator.
The first, if required, besides the operator to offer direct assistance. The second,
external dental assistant, with the purpose to avoid external contamination outside
the “high-risk zone” that consists of a perimeter line separated at least 3 feet from
the main operator and patient’s mouth.
Personal Measures to Protect Dental Healthcare Workers
Dentists and coworkers (dental assistant, collaborators, partitioners, etc.) have
always used PPE. Nevertheless, due to the nature of the new CoV and different risks
of transmission, adjunctive PPE must to be integrated in daily practice along with
those already used. In this context, the authors consider the main operator (dentist
or dental hygienist) the worker that perform the dental procedure. The operator can
work alone or he/she may need of assistance by a dental assistant (or nurse). Whenever
possible, the operation should work alone in the “high-risk zone.” Nevertheless, it
should not improve own risks or risk for cross infections.
According to the Center for Control Diseases, N-95 respirators without exhalation
valve or surgical masks must be used. The closest European equivalent to N95 are the
filtering face piece (FFP2) face mask. Both are suitable for CoVs disease prevention
and are suggested for dental health care workers. The main differences between this
PPE is that the edges of the mask are not designed to form a seal around the nose
and mouth. So with surgical mask is mandatory a full covered face shield.[9 ] Dentists that use dental loupes must wear N95 (or FFP2) mask. Dental loupes should
allow eye protection. Nevertheless, companies are producing specially designed face
shield to be used in conjunction with dental loupes. Same products:
Dental protective face shield designed to be easily decontaminated with alcohol or
immersion disinfection contributes to protect the mouth and noise from aerosol, as
well as other exposed mucous membranes, which includes the eyes. The face shield should
have at least two protective transparent shield (one is for substituted) and cover
all the face including lateral portion.
Disposable full-length gown made of fluid-resistant material.
Gloves have always played a very important role in the disease prevention in medicine,
but there is “little widespread evidence” that they are useful for members of the
public. Dental health care workers must wear gloves as usual. It is authors' opinion
that there is no need to wear a double pair of gloves in the daily practice for personal
protection. Nevertheless, to reduce possible cross infection, a second pair of gloves
could help dental health care workers to reduce risk of contamination during disposable
PPE discharging (layered undressing).
A head covering that provides an effective barrier is recommended during any procedure
that is likely to result in the splattering of blood or aerosol. It is authors’ opinion
that shoe covering are not mandatory to reduce the spread of CoV. Nevertheless, workers
can use it if they want.
To maintain the greatest possible distance, dental assistant should assist while standing.
Main operator must have maximum care during prosthetic procedures that may require
adjustment in adjacent room (i.e., dental laboratory). If possible he/she should delegate
this procedure, avoiding PPE discharging and wearing.
Most of disposable PPE are designed for single-use and must be accurately discarded
after every patient. For example, according to the manufacturer some face mask could
be used up to 8 hours (if not directly contaminated). Others could be sterilized up
to 200 times. It is most important to carefully read and follow manufacture instruction.
Work uniforms cannot be taken at home. They must to be washed in office following
specific programs, or better yet, handled by a dedicate external laundry that also
provided pickup and delivery service.
Further considerations regard the availability of a serological test able to measure
the amount of antibodies against COVID-19. This test should be performed regularly
to eventually make an early diagnosis of exposed workers. This allows for early care
of the worker, but also preventing the spread of the virus.
Measures to Reduce Risks of Cross Infection after Patient Treatment
All the dental clinics must establish a proper protocol including a strictly workflow
to manage patient discharging and dental room cleaning and decontamination before
treating next patient. This includes higher time compared with pre-COVID-19 scenario.
Dental clinics must consider that in this period, overall number of patients per day
must to be reduced allowing for more time to establish proper procedures before and
after dental treatments.
After dental procedure, all the disposable PPE must carefully discard, starting to
help patients to properly leave the dental chair.
Then, all the main operators must properly wash their hands, arms, and face. At this
point, the dentists may bring the patient to the office (or away from the clinic),
while both assistants take care of the dental room cleaning and sterilization.
All the surfaces in the “high-risk zone” must be carefully and properly decontaminated,
including not disposable PPE. External assistant must control all the used materials
and instruments taking care to reduce as soon as possible risks of contamination during
and between dental procedures. It is of importance that external assistant clearly
establishes the perimeter of the “high-risk zone” and also she/he takes care to avoid
contamination outside this area. She/he also must control possible contamination outside
the “high-risk zone” during dental treatment and provide best decontamination accordingly
(moving to dental laboratory for adjustments).
It is important to respect the time needed to kill or inactivate microorganisms. Dental
clinics must use proper disinfectants certified for CoVs and respect its protocol.
During dental room cleaning and sterilization, the assistants must to wear PPE.
Frequent hand washing with proper soap is needed during all of these phases.
Regarding sterilization procedures, at the time of writing this narrative review,
there is no evidence that adjunctive procedures are needed. Dental clinics should
be already organized with high-quality instruments for the decontamination process
in practice and clinic.
There is no evidence about patient discharge/management at the office level. The secretary
must use same PPE as dental operator, limited to face mask and gloves, always maintaining
social distance of at least 3 feet. In addition, some companies are providing plastic
face screen to install to the desktop for operator and patient protection. It’s authors'
opinion that after dental procedure the patients could be contaminated form own aerosol
generated during dental procedure. To reduce possible contamination, next appointments
and payments could be manage as follows:
Next appointment and payment could be managed before dental procedure.
Electronic payment should be preferred.
If a companion is present, he/she can manage appointment and payment.
Next appointment and payment could be managed by phone at later stage.
All the desktop and potentially contaminated surfaces must be carefully decontaminated.
General Recommendations for the Dental Healthcare Workers and the Public
Promote frequent and thorough hand washing with proper soap, including by providing
workers, customers, and worksite visitors with a place to wash their hands.
Encourage workers to stay home if they are sick (fever, cough, and difficulty breathing)
and seek medical care early as follows:
Practice respiratory hygiene encouraging respiratory etiquette, including covering
coughs and sneezes.
Maintain social distancing when possible, avoiding assembly of people through a well-organized
rescheduled program of the appointments.
Avoid touching eyes, nose, and mouth.
Carry put cleaning and decontamination of the used surfaces outside the dental room
(i.e., keyboard, mouse, pen, desks, tables, telephones, etc.).
Stay informed and follow advice given by your health care provider
Discussion
At today more than 22 million cases have been confirmed and they are likely to increase,
so pandemic is far to disappear. The WHO expects 2 years for the end of the pandemic,
assuming a fast availability of an effective vaccines. To make this situation worse,
recently, most of the infected people were asymptomatic or paucisymptomatic, and their
viral load seems to be improved.
As aforementioned explained, the objective of this review article was to share a preliminary
opinion about the disease, the possible ways of treat dental patient, and all the
effort to prevent dental healthcare workers and patient cross infection in this early
stage of COVID-19 outbreak. Concerning our dental clinics and the consolidated use
of PPE by dental operators, it is authors' opinion that the main not-clinical problems
could be the difficulties to purchase PPE, the unknown patient feel and reaction,
and the unavoidable economic crisis. Industry is quickly developing PPE to improve
their availability. Regarding patients’ feel and economic crisis, at the moment, it
is not possible to expect when the COVID-19 pandemic and social distancing will end,
and what will be the consequences. People will always need to take care of their teeth,
but maybe, there will be some changes in their priority and maybe the need for sustainability
treatments. Moreover, a fear of a “second wave” may complicates further scenario.
Regarding the dental-related concerns, it is authors’ opinion that the main problems
are to ensure the highest level of safety for our staff, patients, and family. In
this way, prevention at the beginning and the proper controls of cross infection at
the later stage are the main important area to improve in our workflows.
Routine cleaning of the workplace, without additional disinfection is recommended
at this time. Particular attention to clean the frequently touched surfaces, such
as workstations, counter-tops, and door handles. The cleaning agents used in a dental
workplace are suitable for the disinfection. Nevertheless, the directions on the label
must to be adored to. To improve contamination control, disposable wipes should to
be placed nearly the commonly used surfaces (e.g., doorknobs, keyboards, remote controls,
and desks).
Dentists must provide proper PPE for all the staff, and update the document of risk
assessment, including all the procedures needed to reduce overall risks, as explained
in this document. The deleted appointments should be reschedule giving a list of priority
to reduce the number of patients per day, starting from urgent therapy. This may help
dental assistant to perform all the needed procures to clean and decontaminate the
potentially contaminated surfaces.
Due to the characteristics of dental workplace, the risk of cross infections may be
high be-tween dental healthcare workers and patients, mainly due to aerosol-generating
procedures.[10 ]
[11 ]
[12 ]
[13 ]
[14 ]
[15 ] Prevention still remains the first and most important step to reduce risk that potentially
infected people coming in the clinic. Within this, telephone triage could be an important
starting point for future perspectives, such as telemedicine and virtual patient management.[16 ] Then a well-established chain of control has been proposed to reduce risk of contamination
before during and after the treatment. Dentists and dental assistants already use
PPE during their daily practice.[11 ]
[12 ]
[13 ] Nevertheless all the staff, including, not health workers must to be trained for
PPE use. Moreover, protection from a virus is a challenge because it is not possible
to see it. In this context, definition of different risk zones could help dental healthcare
workers to manage all the procedures act to protect from and prevent cross infections.
The red zone required high level of personal protection and accurate decontamination
of the surfaces. The orange zone required general personal protection and accurate
decontamination of the surfaces. All the dental clinic should be considered potential
source of contamination due to public place, so it is not possible to exclude possible
contamination. For the latter, yellow zone only required general rules, such us social
distance, frequent, and thorough hand washing as well as avoid touching eyes, nose,
and mouth.
Human-to-human transmissions have been described with incubation times between 3 and
14 days via droplets, contaminated hands, or surfaces. According to the WHO seems
that the COVID-19 is mainly transmitted through contact with respiratory droplets
rather than through the air. Nevertheless, waiting consistent data, it is supposed
that CoVs could persist on inanimate surfaces form 72 hours up to 9 days, but they
can be efficiently inactivated by surface disinfection procedures.[14 ]
[15 ] Adopting the proper operative workflow, management of the risk zones and generals
rules, including standard ventilation, extensive decontamination procedures at the
end of a daily work seem not to be justified.
People can be infected everywhere, including dental clinic. Nevertheless, at the date
of writing this manuscript, any outbreaks in a dental clinic was noted. The higher
risks seem to be in restaurants, beaches, logistics, disco, and nursing homes. Moreover,
many of Italy’s recent confirmed cases of COVID-19 are from Italians traveling back
from high-risk zones to their homes. Compulsory swabs for travelers as well as serological
blood-based test for workers could be very helpful to evaluate quarantine in case
of infection and to potentially identified infected patients before treatment.
Finally, the COVID-19 global pandemic continues to have devastating health, economic,
and social effects, and dentistry is not excluded. However, rather than resuming normal
service, this crisis presents an opportunity to rethink the future of dentistry and
address system-level failures, as an opportunity to improve. For instance, dental
professional contributed to create printed plastic valves to mitigate the shortage
of respiratory devices during the COVID-19 epidemic by adapting the dental digital
workflow and converting snorkeling masks in emergency “continuous positive airways
pressure” devices.[17 ]
Summary
The present narrative review offers deeper knowledges and discussion regarding recommended
procedures aimed to reduce risk for dental healthcare workers contamination and cross
infection. Dental office prevention of coronavirus infection, including triage, respect
of general rules, containment measures, proper use of the PPE, and well-organized
chain control of all the staff, with definition of risk zones and specific responsibility
still remain the most important steps to control the spread of the disease.
