Environmental

Health and
Safety

MB-EHSE

1
Environmental
Health and Safety
• Chapter 19: Disease Transmission and Infection Prevention
• Chapter 22: Regulatory and Advisory Agencies
• Chapter 23: Chemical and Waste Management
• Chapter 24: Dental Unit Waterlines
• Chapter 25: Ergonomics
• Online WHMIS Course (Workplace Hazardous Materials Information
System).

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WHMIS COURSE
“SAFE AND
CERTIFIED”
 Students will receive an email from the WHMIS
course. It is a mandatory component of EHSE.
Final marks for EHSE cannot be reported until we
have received the certificates showing course
completion.
 Students do not need to send instructors their
certificates, instructors will automatically be sent
them upon completion. If students want to keep a
copy, it is your responsibility to print it for your
own use.

• This will need to be completed by:

February 23rd, 2024.

3
 Environmental
Health and Safety

Duration of Test Date: Completion of Value: Test = Assignments(2) Passing Grade:

Subject: 15 February 23/24 Online WHMIS 70% = 30% 70%
hours Course
What to expect:
35 Questions
1 hour 15 minutes
30 Multiple Choice
5 Diagrams
24.5/35 = 70% ~
10.5 incorrect

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Disease
Transmission
and Infection
Prevention

Chapter 19
5
Introduction

 The dental assistant is at risk of

exposure to disease through
contact with blood and other
potentially infectious materials

 By carefully following infection

control and safety guidelines,
you can minimize your risk of
disease transmission in the
dental office

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The Chain of
Infection
 Consists of four parts:

1) Virulence
2) Number of Microorganisms
3) Susceptible host
4) Portal of entry

At least one part of the chain must be

removed to break the chain of infection

 Asepsis:
• being free from pathogenic
microorganisms

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Virulence

• Refers to the degree of

pathogenicity or strength of that
organism in its ability to produce
disease
• We cannot change the virulence of
microorganisms, so we must rely
on our body defenses and specific
immunizations
• Avoid contact with microorganisms
by always using infection control
techniques

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Number of
Microorganisms
• Pathogenic microorganisms must also be
present in large enough numbers to
overwhelm the body’s defenses
• Number of pathogens may be directly
related to the amount of bioburden present
• “Bioburden” is organic materials such as
blood and saliva
• Use of the dental dam and high-volume
evacuation helps minimize bioburden on
surfaces and reduce the number of
microorganisms in the aerosol

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Susceptible Host

• A person who is unable to

resist infection by the
pathogen
• An individual who is in poor
health, chronically fatigued, or
under extreme stress or who
has a weakened immune
system is more likely to
become infected
• Staying healthy, washing
hands frequently and keeping
immunizations up-to-date will
help members of the dental
team resist infection and stay
healthy

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Portal of Entry

 To cause infection, a pathogen must

have a portal of entry (or a way of
getting into the body)
 The portals of entry for airborne
pathogens are the mouth and nose
 Blood-borne pathogens must have
access to the blood supply to gain
entry into the body
• This occurs through a break in
the skin caused by a needle
stick, a cut or even a human
bite
• Can also occur through mucous
membranes of nose and oral
cavity
 Parenteral transmission occurs
only through a break in the skin

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Types of
Infections

 Acute infection
• Symptoms are often quite severe and
appear soon after the initial infection
occurs
 Chronic infection
• The microorganism is present for a
long period; sometimes for life
 Latent infection
• A persistent infection in which the
symptoms come and go; cold sores
fall in this category
• Oral herpes simplex and genital
herpes are latent viral
infections
 Opportunistic infection
• Caused by normally non-pathogenic
organisms, opportunistic infections
occur in individuals whose resistance
is decreased or compromised

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Modes of Disease Transmission

Direct transmission

• The most common route is through direct

contact (touching) with the patient’s blood
or saliva
• Occurs when someone comes into direct
contact with the infectious lesions or
infected body fluids
e.g. blood, saliva, semen, vaginal
secretions


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Modes of Disease Transmission

INDirect transmission

 Involves the transfer of organisms to a susceptible

person
• This can happen through:
 the handling of contaminated instruments
touching of contaminated surfaces and then touching
the face, eyes or mouth
Fomites: objects or materials which are likely to carry
infection, such as doorknob, telephone, clothes, and
furniture etc.
 An example of inanimate objects that are capable of
transmitting infection/disease by indirect contact:
Someone sneezes on their hand and then touches the
item, next person to touch the item is indirectly infected

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Pathogens can be transferred from staff
to patient, patient to staff and patient to
patient through contaminated
equipment.

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 Modes of Disease Transmission

Airborne transmission

 Also known as droplet infection, involves the spread of

diseases through droplets of moisture containing bacteria
or viruses

Aerosols from a highspeed handpiece.  Aerosol, spray or spatter

• Contain saliva, blood and microorganisms, are created with

the use of the high-speed handpieces, air-water syringe and
ultrasonic scaler during dental procedures
• Mists are droplet particles larger than those generated in
aerosol spray
• Spatter is large droplet particles contaminated with blood,
saliva and other debris
• Happens during a dental procedure when the mucosa
(mouth or eyes) or non-intact skin is splashed with blood or
blood-contaminated saliva

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Aerosols from an ultrasonic scaler.
Modes of
Transmission

 Parenteral transmission
• Parenteral means through the skin,
as with cuts or punctures. Can take
place through needle stick injuries,
human bites, cuts, abrasions or any
break in the skin
 Blood-borne transmission
• Involves direct or indirect contact
with blood and other body fluids
• Remember, although blood may not
be visible in the saliva, it still may be
present.

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 Food and water transmission

Occurs when contaminated food that

has not been cooked or refrigerated
properly or water that has been
contaminated with human or animal
fecal material is consumed

Fecal-oral transmission

Occurs when proper sanitation

procedures, such as handwashing
after use of the toilet, are not
followed and one of the many

Modes of Transmission
pathogens present in fecal matter is
transmitted when the infected person
touches another person or makes
contact with surfaces or food

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Transmission

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 • The human body receives resistance to communicable
diseases from the immune system
The Immune System • A communicable disease is one that can be transmitted
from one person to another or by contact with the body
fluids from another person
• Inherited immunity is present at birth
• Acquired immunity is developed over a person’s
lifetime

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Acquired
immunity

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 Naturally acquired immunity occurs when a person has
contracted and is recovering from a disease
• Active immunity occurs because the body of the host is
actively involved in the process
The Immune • Passive immunity occurs during pregnancy when the fetus
receives antibodies from the mother’s placenta
System Artificially acquired immunity
• Antibodies are introduced into the body by means of
immunization or vaccination

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 24

IF SALIVA WERE RED

https://www.youtube.com/watch?v=r
saN-gWBa44
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Disease
Transmission in
the Dental Office
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Patient to Dental
Team
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Patient to Dental Team

 28

Dental Team to
Patient
 29

Patient to Patient
 30

Dental Office to
Community
 31
Community to Dental
Office to Patient
Transmission
 32
Roles and Responsibilities
of the CDC and OSHA in
Infection Control
  The most important infection control law in dentistry
OSHA Blood-
Borne • Designed to protect employees against occupational exposure
to blood-borne pathogens, such as hepatitis B, hepatitis C and
Pathogens human immunodeficiency virus (HIV)

Standard • Employers are required to protect their employees from

exposure to blood and other potentially infectious materials
(BBP) (OPIM) in the workplace and to provide proper care to the
employees if an exposure should occur

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 The BBP applies to any type of facility in
which employees might be exposed to blood
and/or other body fluids, which include:

Dental and Emergency

Funeral Nursing
OSHA Blood- medical
offices
Hospitals
homes
medical
services
homes

Borne
Pathogens
Standard
(BBP)
OSHA requires that a copy of the BBP be
present in every dental office and clinic

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Exposure Control Plan

Universal Precautions is
Clearly describes how
referred to in the OSHA
the office complies
Blood-borne Pathogens
with the standard
Standard (BBP)

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Standard and
Universal Precautions
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Standard and
Universal Precautions
 38

Standard
Precautions
Wash and Sanitize • Wash hands before and after every patient

• Wear gloves when touching blood, body fluids, secretions, and

Protect yourself contaminated items

Be careful • When handling sharps

• Wear a mask and eye protection, or a face shield, during

Protect yourself procedures likely to generate splashes or sprays

• Carefully handle contaminated patient care items to prevent

Be careful the transfer of microorganisms to people or equipment

• Use a mouthpiece or other ventilation device as an alternative

Protect yourself to mouth-to-mouth resuscitation when practical

• Standard Precautions when treating of all patients depending

Apply on risk of exposure
 Occupational Exposure Determination

Category Definition Example

Categories
I Routinely Dentist, dental hygienist, of Employees
exposed to dental assistant, dental
blood, saliva or sterilization assistant, dental
both laboratory technician The OSHA BBP Standard
requires employers to
categorize tasks and procedures
II May on Receptionist or office during which an employee
might experience occupational
occasion be manager who may
exposure
exposed to occasionally clean a BBP defines an occupational
blood, saliva or treatment room or handle exposure as “any reasonably
both instruments or impressions anticipated skin, eye, mucous
membrane contact, or
percutaneous injury with blood
III Never exposed Financial manager, insurance or any other potentially
to blood, saliva clerk or computer operator infectious materials”
or both

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Post Exposure
Management

• Accidents happen!
• Before an accident occurs, the
BBP requires the employer to
have a written plan
• This plan explains exactly what
steps the employee must follow
after the exposure incident
occurs and the type of medical
follow-up that will be provided
to the employee at no charge*

*keeping in mind that in the U.S.,

they have to pay for medical
services

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Follow-Up
Measures for
Exposed Workers

• The following services must be offered

to the employee without charge
• Confidential medical counselling
• Human immunodeficiency virus
(HIV) test series immediately and
at 6 weeks, 12 weeks and 6
months
• Hepatitis B virus (HBV) immune
globulin (if no prior HBV
vaccination)
• Tetanus booster
• Documentation of incident on
appropriate Occupational Safety
and Health Administration
(OSHA) form
****KNOW!!

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Employee
Training
 43

Hepatitis B
Immunization
 Standard
hepatitis B
virus (HBV)
informed
refusal.
 45

Hepatitis B
Immunization
 46

Post Vaccine
Testing
Need For a Booster
 Routine booster doses of the HBV vaccine
are not recommended by the CDC
 The CDC does not recommend routine
blood testing, to monitor the HBV antibody
level in individuals who have already had
the vaccine
• The exception to this recommendation
is if an immunized individual has a
documented exposure incident and the
attending physician orders the
administration of a booster dose

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Employee
Medical Records
Managing
Contaminated
Sharps
Contaminated needles and other disposable
sharps, such as scalpel blades, orthodontic
wires and fragile or broken glass, must be
placed into a sharps container

The sharps container must be puncture-

resistant, closable, leak-proof and colour-coded
or labeled with the biohazard symbol

Sharps containers must be located as close as

possible to the place of immediate disposal

Do not cut, bend or break the needles before

disposal

Never attempt to remove a needle from a

disposable syringe

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Preventing Needle Sticks
(Parenteral transmission)
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Hand Hygiene:
Handwashing
Guidelines
Areas of the hand not thoroughly washed because of poor handwashing technique.

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Hand Hygiene:
Handwashing
Guidelines
 Faucets may have been contaminated by
being touched with soiled or contaminated
hands.
 If sink is not hands-free(motioned
censored or foot pedal operated) use clean
paper towel when turning on and off
water.
 Vigorously rub together the lathered hands
under a stream of water to remove surface
debris. Repeat again for ten seconds.
 Remember to rinse the hands with cool
water afterwards. Reason being is cool
water closes the pores.

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Additional
Handwashing
Guidelines
 56

Alcohol-Based
Hand Rubs
 57
Hand Care
Recommendations
 58
Personal Protective
Equipment
Personal Protective
Equipment 59
Protective Clothing 60
Protective
Clothing(PPE) 61
Requirements
Guidelines for the Use of
Protective Clothing

Because protective clothing can spread contamination, it is not worn

out of the office for any reason, including travel to and from the office

Protective clothing should be changed at least once daily and more

often if visibly soiled

If a protective garment becomes visibly soiled or saturated with

chemicals or body fluids, it should be changed immediately

Protective clothing must not be worn in staff lounge areas or when

workers are eating or consuming beverages

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Handling
Contaminated 63
Laundry
 64

Protective Masks
 65

DO NOT!!
Guidelines for the Use
of Protective Masks
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 67

Protective
Eyewear
 68

Face Shield
 69

Patient Eyewear
 70

Gloves
Guidelines for the Use
of Gloves
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 72
Gloves Damaged
During Treatment
 73
Gloves Damaged by
Dental Materials
 74

Examination
Gloves
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Overgloves
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Guidelines for the
Use of Overgloves
Sterile Surgical
Gloves

Sterile gloves should be worn for

invasive procedures involving the
cutting of bone or significant
amounts of blood or saliva, such as
oral surgery or periodontal treatment
Sterile gloves are supplied in pre-
packaged units to maintain their
sterility before use
They are provided in specific sizes
and are fitted to the left or right
hand
• They are not ambidextrous

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Utility Gloves
 Utility gloves are not used for direct patient
care
 Utility gloves must be worn:
• When the treatment room is being
cleaned and disinfected between patients
• While contaminated instruments are
being cleaned or handled
• For surface cleaning and disinfection
 Utility gloves may be washed and disinfected or
sterilized and reused
 Protects against Parenteral transmission
 Used utility gloves must be considered
contaminated and handles appropriately until
they have been properly disinfected or sterilized

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Non-Latex
Containing Gloves
Maintaining Infection Control
While Gloved

• During a dental procedure, it may

be necessary to touch surfaces or
objects such as drawer handles or
material containers
• If you touch these objects with a
gloved hand, both the surface and
the glove become contaminated
• To minimize the possibility of cross-
contamination, use an overglove
when it is necessary to touch a
surface
Aseptic retrieval using sterilized cotton pliers
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issued for each patient.
Maintaining Infection Control
While Gloved

Opening Drawers and Cabinets

• Set up instruments, medications
and impression materials ahead of
time, and use disposable and unit-
dose items whenever possible
Opening containers
• When opening a container, use
overgloves, a paper towel, or a
sterile gauze sponge to remove
the lid or cap
• Use sterile cotton pliers to remove
an item from a container or
drawer

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 High-Tech
Equipment

• Every aspect of dentistry is

entering the arena of high-
technology equipment and
devices
• You must carefully consider
what infection control
procedures are needed to make
each piece of equipment safe
to use
• Always follow manufacturer’s
infection control
recommendations for every
device and piece of equipment

Computer keyboard with a smooth surface that allows for

effective cleaning and disinfection

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Latex Allergies
 84

Latex Allergies
 85

Irritant
Dermatitis
 86

Type IV
Allergic
Reaction
 87

Type I Allergic
Reaction
 88
There is no specific cure for latex allergy
Treatment The only options are prevention,
avoidance of latex-containing products and
treatment of the symptoms
Anyone who suspects that he or she has an
allergy to latex should see a qualified
healthcare provider to have a test to
confirm the allergy
Once a latex allergy has been diagnosed,
the affected person should practice latex
avoidance in all aspects of his or her
personal and professional life
 89
Remember:
Treatment
• When a latex allergy has been diagnosed in
one employee in the dental office, all staff
members should use practices to minimize the
use of latex-containing products
• These practices include the wearing of
powder-free gloves by all dental staff members
to minimize the risk of airborne latex particles
It is a good idea to wear powder-free
gloves to prevent the development of latex
sensitivity
• If you know that your next patient has a latex
allergy, do not even wear latex gloves to set up
the treatment room
 90

Latex-Sensitive
Patients
 91
Use non-latex containing blood pressure cuffs.
Latex- The latex-allergic patient should be scheduled as
Sensitive the first patient of the day to minimize the quantity
of latex proteins in the air.
Patients No latex should be present in the treatment room.
The treatment room that is to be used for latex-
allergic patients should be located near an outside
entrance (to prevent the patient from traveling
through a large dental suite, where latex from
other activities may be present).
Ensure that no one who has worn latex that day
enters the treatment room when a latex-allergic
patient is being treated (latex particles can remain
on clothing, hair, shoes, etc.).
 92
Waste Management
in the Dental Office
Classification of Waste

General Waste
• All nonhazardous, nonregulated waste should be discarded in covered containers
• Examples include disposable paper towels, paper mixing pads, and empty food
containers
Contaminated Waste
• Waste that has had contact with blood or other body fluids
• Examples include used barriers and patient napkins
Hazardous Waste
• Poses a risk to human beings and the environment
• Toxic chemicals and materials are hazardous waste
• Examples include scrap amalgam, spent fixer solution and lead foil from x-ray film
packets

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Classification of Waste

Infectious or Regulated Waste

(Biohazard)

• may be both hazardous waste (because of

the amalgam) Contaminated waste that is
capable of transmitting an infectious
disease
• Some items, such as extracted teeth with
amalgam restorations, and infectious
waste (because of the blood)
• Most dental offices are exposed to the
following types of infectious waste:
• Blood and blood-soaked materials
 Blood or saliva can be squeezed
out
• Pathologic waste
• Sharps

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Handling of Extracted
Teeth

• Dispose of extracted teeth as regulated medical

waste unless they are being returned to the
patient
• When teeth are returned to the patient, the
provisions of the standard no longer apply
• Do not dispose of extracted teeth containing
amalgam in regulated medical waste that will be
incinerated
 Some dental schools will accept them as
donations so students studying dentistry
can practice cavity preparations on them
• Note: Because of the mercury in amalgam
fillings, you should check with local authorities
for regulations regarding disposal of teeth
containing amalgam

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Handling of
Contaminated Waste
Contaminated items that may contain body
fluids, such as gloves and patient napkins,
should be placed in a lined trash receptacle

A receptacle for contaminated waste should be

covered with a properly fitted lid, opened by a
foot pedal

Keep the lid closed to prevent air movement

and the spreading of contaminants

Red bags or containers should not be sued for

unregulated waste

Check the specific requirements of your local

health department

Waste is separated into clearly marked containers

Left, Unregulated Waste 96

Right, Regulated Waste

Handling of
Medical Waste

• Medical waste
 Any solid waste generated in the
diagnosis, treatment or
immunization of human beings or
animals in research
• Infectious waste
 A subset of medical waste
 Containers of infectious waste
(regulated waste) must be
labeled with the universal
biohazard symbol, identified
in compliance with local
regulations, or both
 Containers used for holding
contaminated items must be
labeled

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Disposal of Medical Waste

Once contaminated waste leaves the office, it is regulated by the EPA and
by local laws

Under most regulations, the manner of disposal is determined by the

amount (weight) of infectious materials requiring disposal

The average dental practice is categorized as a “small producer” of

infectious waste, and disposal is regulated accordingly

The law required the dentist to maintain records of the final disposal of this
medical waste, including documentation of how, when and where it was
disposed of

98
Additional Infection Control Practices

OSHA Blood-Borne Pathogens Standard

OSHA Blood-Borne Pathogens Standard

• Never eat, drink, smoke, apply cosmetics
or lip balm, or handle contact lenses in
any area of the dental office where
contamination is possible, such as the
dental treatment rooms, dental
laboratory, sterilization area or the are for
the processing of radiographs
• Never store food or drink in a refrigerator
that contains any potentially
contaminated items
• You can minimize the amount of splash
and spatter contamination produced
during dental procedures with the skilful
use of a dental dam and high-volume
evacuation

99
 CDC Guidelines:
Special Considerations

Saliva ejectors

Anti-retraction
• Do not advise patients to close their lips
tightly around the tip of the saliva ejector to
evacuate oral fluids Unless anti- retraction
device is attached.
• Many patients have become accustomed to
closing their lips around the suction

100
 CDC Guidelines:
Special Considerations
Dental Laboratory
• Use PPE when handling items in the laboratory until they
have been decontaminated
• Discard any packaging material used in the transport of
dental cases immediately, to and from the dental laboratory
as it may be contaminated
• Clean, disinfect and rinse all dental prostheses and
prosthodontic materials
 Examples: impressions, bite registrations, occlusal rims
and extracted teeth
• Consult with manufacturers regarding the stability of specific
materials (impression materials) relative to disinfection
procedures
• Clean and heat-sterilize heat-tolerant items used in the
mouth
• Follow manufacturers’ instructions for cleaning, sterilizing or
disinfecting items that become contaminated but do not
normally come into contact with the patient
• Please refer to Procedure 19.6 on Page 308; Disinfecting an
Alginate Impression for instructions on how to disinfect an
alginate impression

101
 CDC Guidelines:
Special Considerations

Procedural Mouthrinses

• Intended to reduce the number of

microorganisms released in the form of
aerosol or spatter
• Can decrease the number of
microorganisms introduced into the
patient’s bloodstream during invasive
dental procedures

102
 CDC Guidelines:
Special Considerations

Mycobacterium Tuberculosis

• For patients with known or suspected

active TB, the CDC recommends that
elective dental treatment be delayed until
the patient in non-infectious
• For patients who require urgent dental
care, the CDC recommends referring the
patient to a facility with TB engineering
controls and a respiratory protection
program

103
 • In surgical procedures involving the use of a laser or electrosurgical unit, a
smoke by-product is created during the thermal destruction of the tissue
CDC Guidelines: • Laser plumes and surgical smoke pose a risk to dental healthcare
Special Considerations professionals
• The effect of the exposure (e.g., disease transmission or adverse
Laser/Electrosurgery Plumes or respiratory effects) in dental healthcare professionals resulting from the
use of lasers in dentistry has not been adequately evaluated (unresolved
Surgical Smoke issue)

104
 rings

• Because rings and long

fingernails can harbor
pathogens, nails should be
kept short and well
manicured. Rings, long nails,
and artificial nails are likely to
puncture examination gloves
and may poke a patient
during an examination. In
addition, microorganisms
thrive around rough cuticles
and can enter the body
through any break in the skin.
The CDC Guidelines
recommend that rings,
fingernail polish, and artificial
nails should not be worn at
work. (Category II)

105
Applying First Aid
After an Exposure
Incident

• Procedural Steps
• 1 Stop operations immediately.
• 2 Remove your gloves.
• 3 Wash your hands thoroughly, using antimicrobial
soap and warm water.
• 4 Dry your hands.
• 5 Apply a small amount of antiseptic to the
affected area.
• NOTE Do not apply caustic agents such as
bleach or disinfectant solutions to the wound.
• 6 Apply an adhesive bandage to the area.
• 7 Complete applicable postexposure follow-up
steps.
• NOTE The employer should be notified of the
injury immediately after initial first aid is provided.

106
Management
of an Exposure
Incident
• Document the route(s) of exposure and the
circumstances in which the incident occurred (e.g.,
cut, needle stick, or blood splash).
• • Identify and document the source individual
(patient whose blood or body fluid is involved in the
exposure incident), unless the employer can establish
that identification is not possible or is prohibited by
state or local law.
• • Request that the source individual have his or her
blood tested for human immunodeficiency virus (HIV)
and hepatitis B virus (HBV) (the source individual can
refuse this request).
• • Advise the employee to have his or her blood
tested for HIV and HBV. (The employee has the right
to refuse to be tested.) By law, the employee’s blood
test results are held confidential from the employer.
• • Provide medically indicated prophylactic treatment,
such as necessary injections of gamma globulin, HBV
vaccine booster, tetanus booster, or a combination. •
Provide appropriate counseling.
• • Evaluate reported illnesses after the incident.

107
 The following services must
• Confidential medical
be offered to the employee
counseling
without charge:

Follow-up
Measures for • Human immunodeficiency
virus (HIV) test series
• Hepatitis B virus (HBV)
immune globulin (if no prior
immediately and at 6 weeks,
Exposed 12 weeks, and 6 months
HBV vaccination)

Worker
• Documentation of incident
on appropriate
• Tetanus booster Occupational Safety and
Health Administration
(OSHA) form

108
 Questions??

Recall 1-30

Critical Thinking 1-4

109