Chapter. 20 Principles and Techniques of Disinfection Flashcards
During patient treatment, surfaces in equipment and treatment rooms are likely to become contaminated with saliva or by aerosol containing blood, saliva, or both
Introductions
During patient treatment, surfaces in
equipment and treatment rooms are likely
to become contaminated with saliva or by
aerosol containing blood, saliva, or both
Laboratory studies have shown that
microorganisms may survive on
environmental surfaces for varying periods
Assume that if a surface has had contact
with saliva, blood, or other potentially
infectious materials, it contains live
microorganisms
Environmental Infection Control
The Centers for Disease Control and
Prevention (CDC) Guidelines for Infection
Control in Dental Healthcare Settings—
2003 divide environmental surfaces into
clinical contact surfaces and housekeeping
surfaces
Housekeeping surfaces include floors,
walls, and sinks
Because they have a much lower risk of
disease transmission, cleaning and
decontamination are not as rigorous as that
for clinical areas and patient treatment items
Cleaning and Disinfecting
Considerations
Amount of direct patient contact
Type and frequency of hand contact
Potential amount of contamination by
aerosol and spray
Other sources of microorganisms (e.g.,
dust, soil, and water)
Clinical Contact Surfaces.1
Can be directly contaminated either by spray or
spatter generated during dental procedures or
by contact with dental professional’s gloved
hands
Current infection control guidelines of the Office
Safety and Asepsis Procedures Research
Foundation (OSAP) recommend that clinical
surfaces be classified and maintained under
three categories
Touch
Transfer
Splash, spatter, and droplet
Clinical Contact Surfaces.2
Touch surfaces are directly touched and
contaminated during treatment procedures
Include handles of dental lights, controls of dental units,
chair switches, chairside computers, pens, telephones,
containers of dental materials, and drawer handles
Transfer surfaces are not directly touched but
often are touched with contaminated
instruments
Include instrument trays and handpiece holders
Splash, spatter, and droplet surfaces do not
actually come into contact with the members of
the dental team or the contaminated
instruments or supplies
Countertops are a major example
Surface Contamination
There are two methods of dealing with
surface contamination
Surface barriers
Precleaning and disinfecting surfaces
between patients
Surface Barriers
Wide variety of surface barriers available today
Should be resistant to fluids to keep
microorganisms in saliva, blood, or other liquids
from soaking through to the surface underneath
Some plastic bags are designed in the shape of
items such as the dental chair, air-water syringe,
hoses, pens, and light handles
Plastic barrier tape is frequently used to protect
smooth surfaces (e.g., touch pads on equipment,
electrical switches on chairs, and x-ray equipment)
Aluminum foil can also be used because it is easily
formed around any shape
Single-Use (Disposable) Items.1
Used on only one patient and then
discarded, so they help reduce the
chance for patient-to-patient
contamination
Single-use items are often made of
plastic or less expensive metals, and
they are not intended to withstand
cleaning, disinfection, or sterilization
Never process (clean, disinfect/sterilize)
single-use items for use on another
patient
Single-Use (Disposable) Items.2
In most areas, contaminated disposable
items that are not sharps and are not
soaked or caked with blood may be
discarded with the regular office trash
There is no need to discard these items
in a medical waste or biohazard
container
State and local regulations may vary, so
always consult the regulatory agency
for your area
Precleaning and Disinfection
Although no cases of cross-infection
have been linked to dental treatment
room surfaces, cleaning and disinfection
of these surfaces are important
components of an effective infection
control program
In addition, the OSHA Blood-Borne
Pathogens Standard requires that
contaminated work surfaces be
disinfected between patient visits
Precleaning.1
Precleaning means to clean before
disinfecting
All contaminated surfaces must be
precleaned before they can be
disinfected
Even if there is no visible blood on a
surface, it must be precleaned because
even a thin layer of saliva on the surface
can decrease the effectiveness of the
disinfectant
Precleaning reduces the number of
microbes and removes blood and saliva
Precleaning.2
Most effective when used on contaminated
surfaces that are smooth and easily
accessible for cleaning
Always wear utility gloves, mask, protective
eyewear, and protective clothing when
precleaning and disinfecting
Surfaces that are irregular or textured are
difficult or impossible to clean or to disinfect
Regular soap and water may be used to
preclean, but it is more efficient to select a
disinfectant that can be used to clean as
well as disinfect
Disinfection
Intended to kill disease-producing
microorganisms that remain on the
surface after precleaning
Spores are not killed during disinfecting
procedures
Do not confuse disinfection with
sterilization
Sterilization is a process in which all
forms of life are destroyed
Disinfectants.1
Chemicals that are applied to inanimate
surfaces (e.g., countertops and dental
equipment)
Antiseptics are antimicrobial agents that
are applied to living tissue
Disinfectants and antiseptics should
never be used interchangeably because
tissue toxicity and damage to
equipment can result
Disinfectants.2
Disinfectants are chemicals that destroy or
inactivate most species of pathogenic
(disease-causing) microorganisms
In dentistry, only those products that are
EPA-registered hospital disinfectants with
tuberculocidal (kills the tuberculosis
bacteria) claims should be used to disinfect
dental treatment areas
Mycobacterium tuberculosis is highly
resistant to disinfectants, and if a
disinfectant will inactivate M. tuberculosis it
will inactivate the less resistant microbial
families (e.g., bacteria, viruses, and most
Ideal Surface Disinfectant
An ideal surface disinfectant would:
Rapidly kill a broad spectrum of bacteria
Have residual activity and minimal toxicity
Not damage the surfaces to be treated
Be odorless and inexpensive
Work on surfaces with remaining bioburden
Be simple to use
No single disinfectant product on the
market today meets all these criteria
When selecting a surface disinfectant,
you must carefully consider the
advantages and disadvantages of
various products
Disinfectant Precautions
Follow manufacturers’
recommendations for:
Mixing and diluting
Application technique
Shelf life
Activated use life
All safety warnings
Iodophors
EPA-registered intermediate-level
hospital disinfectants with
tuberculocidal action
Because iodophors contain iodine, they may
corrode or discolor certain metals and may
temporarily cause reddish or yellow stains
on clothing and other surfaces
Synthetic Phenol Compounds
EPA-registered intermediate-level
hospital disinfectants with broad-
spectrum disinfecting action
Phenols can be used on metal, glass,
rubber, or plastic
May also be used as a holding solution
for instruments; however, phenols leave
a residual film on treated surfaces
Synthetic phenol compound is prepared
daily
Sodium Hypochlorite
Sodium hypochlorite (household bleach)
is a fast-acting, economical, and broad-
spectrum intermediate-level
disinfectant (1:100 dilution for surface
decontamination)
Bleach solution is unstable, must be
prepared daily, has a strong odor, and is
corrosive to some metals, destructive to
fabrics, and irritating to the eyes and skin; it
may eventually cause plastic chair covers to
crack
Alcohol
Alcohols are not effective in the
presence of blood and saliva
Evaporate quickly and are damaging to
certain materials such as plastics and
vinyl
Not recommended as a surface
disinfectant by several agencies
Glutaraldehyde
Classified as a high-level disinfectant/sterilant;
can also be used as a liquid sterilant when
immersion time is greatly increased
Useful for plastics and other items that cannot
withstand heat sterilization
Very toxic; should be handled carefully to avoid
the fumes
Glutaraldehyde-treated instruments should never
be used on patients without first being
thoroughly rinsed with water
Prolonged contact of certain types of instruments
with glutaraldehyde solutions can lead to
discoloration and corrosion of the instruments’
surfaces and cutting edges
Immersion Disinfectants
Some chemicals on the market can be used for
sterilization or high-level disinfection
When used as sterilants, they destroy all
microbial life, including bacterial endospores
Depending on the type, time for sterilization
can range from 6 hours to 30 hours
At weaker dilutions or with shorter contact
time, these chemicals provide high-level
disinfection, inactivating all microorganisms
except endospores
Most of these chemicals are toxic and can
irritate the eyes, skin, and lungs
PPE must be worn when these chemicals are use
Chlorine Dioxide
Chlorine dioxide is an effective, rapid-
acting environmental surface disinfectant
(3 minutes) or chemical sterilant (6
hours)
Chlorine dioxide does not readily
penetrate organic debris and must be
used with a separate cleaner
Chlorine dioxide must be prepared fresh
daily, it must be used with good
ventilation, and it is corrosive to
aluminum containers
Ortho-Phthalaldehyde
Classified as a high-level disinfectant
OPA is effective in achieving high-level
disinfection within 12 minutes at room
temperature
More expensive than glutaraldehydes
but may be a good alternative for
individuals with a sensitivity to
glutaraldehydes
It has very little odor and does not
require activation or mixing
Ortho-Phthalaldehyde Disadvantages
Costly
Can be used only half as long as most
glutaraldehydes in dentistry
May stain skin and fabrics
Plastics turn a blue-green color where
proteins have not been removed
Would require more than 30 hours to
secure sterilization
Evacuator System
High-volume evacuation reduces the
risk of saliva escaping from patients’
mouths
Regular cleanings help tubes and pipes
flow easier
Clean by flushing with detergent or water
Periodically clean the traps
Housekeeping Surfaces
No scientific evidence showing that
housekeeping surfaces (e.g., floors, walls, and
sinks) pose a risk for disease transmission in
dental healthcare settings
Majority of housekeeping surfaces need to be
cleaned only with a detergent and water or an
EPA-registered hospital disinfectant/detergent
However, used solutions of detergents or
disinfectants—especially if prepared in dirty
containers, stored for long periods of time, or
prepared incorrectly—may be reservoirs for
microorganisms
Make fresh cleaning solution each day; discard
any remaining solution and let the container dry
Carpeting and Cloth Furnishings
Carpeting is more difficult to clean than is
nonporous hard-surface flooring, and it cannot
be reliably disinfected, especially after
contamination with blood and other body
substances
Studies have documented the presence of
bacteria and fungi in carpeting
Cloth furnishings pose similar contamination
risks in areas where direct patient care is
performed and where contaminated materials
are handled
CDC guideline: Avoid using carpeting and cloth-
upholstered furnishings in dental operatories,
Spills of Blood and Body
Substances
The majority of blood contamination in dentistry
results from spatter and the use of rotary or
ultrasonic instruments
No scientific evidence shows that HIV, HBV, or
HCV has been transmitted from a housekeeping
surface
OSHA requires that blood spills and other body
fluids be removed and the surfaces disinfected
CDC guideline: Clean spills of blood or other
potentially infectious materials and
decontaminate the surface with an EPA-
registered hospital disinfectant with low-level to
intermediate activity, depending on the size of
Greener Infection Control.1
Protecting the environment has become
an important part of our personal lives
and in our homes
That responsibility extends to the provision
of dental care
Many of the infection control products
and procedures we must use to protect
our patients and ourselves have a
negative impact on the environment
Greener Infection Control.2
By altering a process or a material, it is
possible to minimize a potentially
negative impact on the environment
For example, using disinfectant wipes
instead of spraying disinfectants could
reduce the amount of chemicals in the
air
Going greener requires thoughtful
planning, research, and
experimentation
Greener Infection Control.3
Paper
Digital patient records could have a significant
impact on the amount of paper that is used
Radiology
Digital radiology is rapidly becoming state-of-
the-art
Personal protective attire
Protective barriers present a challenge in the
attempt to go greener; some are recyclable
Surface barriers and
precleaning/disinfection
Involves the use of chemicals and PPE
