Sterilisation & disinfection /certified fixed orthodontic courses by Indian dental academy

STERLIZATION
AND
DISINFECTION
INDIAN DENTAL ACADEMY
Leader in continuing dental education
www.indiandentalacademy.com

INTRODUCTION
Dental care professionals are at an
increased risk of cross infection while treating
patients.
• This occupational potential for disease
transmission become evident initially when
one realises that most human microbial
pathogens have been isolated from oral
secretions. Because of repeated exposure to
micro-organisms in blood and saliva,
incidence of certain infectious diseases has
been significantly higher among dental
professionals than observed for general

•Although there is common goal in infection
control ,there are several approaches that may
be used to achieve the desired result.These
approaches vary from office to office depending
on type of dental procedure performed ,number
and training employees,and type of equipment
used.

 Part of the problem lies in the fact that
many practitioners and auxillaries
previously failed to appreciate the
infection potential presented by saliva and
blood during treatment.
 These dangers often we dismissed
because much of spatter coming from
patients mouth is not noticed readily.

HISTORY
 The science of microbiology has shed
much light on the nature of disease. In
the nineteenth century the work of
Pasteur ,Lister and Koch did much to
explain the role of bacteria in disease and
to indicate possible methods of practicing
safer medicine.
 LOUIS PASTEUR (1822-95) was the first
scientist to show clearly that bacteria
never generate spontaneously and that no
growth of any kind occurs in the sterilized
media. www.indiandentalacademy.com

 One of his many achievements was the
development of the technique of
controlled heating known as
‘PASTEURISATION’ for the preservation of
beverages and food stuffs.
 By his experimental studies on anthrax in
1876-77, he was to prove that a certain
type of infection invariably occurred when
a number of micro-organisms of a
particular kind were introduced to the
body..

If I had the honour of being a surgeon,
impressed as I am with the dangers of
exposure to the microbes scattered of all
objects, not only would I use perfectly clean
instruments,but after washing my hands with
greatest care and submitting them to rapid
flaming, I would use bandages,previously
exposed in air at 130-150 degreeand use
water which has been submitted to a temp
of 120 degree….this way I would have to
fear only the germs suspended in the air
around the patients bed.”
Louis Pasteur(1878)

Dr. Joseph Lister (1827-1912)
Discovered the effectiveness of 'carbolic acid,‘
which was used in controlling typhoid.
• Using carbolic acid, Lister was able to keep
his hospital ward in Glasgow free of infection
for nine months.
• Lister published the results of his experiments
in The Lancet : 11 cases of compound fracture
without any sepsis.

Carbolic acid spray being used at the
time of a surgery

Influx model carbolic spray, copper,
brass with wood handle


 Robert Koch (1843-1910) was one of
the greatest figures in the development of
microbiology. He had immense skill in
devising new bacteriological techniques.
He was also the first to make
photomicrographs of stained smears, and
in addition he pioneered methods of
growing bacteria on agar media.

 Despite the fact that the germ theory of
disease had been established in 1877, it
was not universally accepted until 1882
when Koch presented his masterly paper
on ‘The aetiology to tuberculosis’ giving
details of the isolation of the tubercle
bacillus. In the following year he isolated
the cholera vibrio.
 The ‘Golden era’ of medical
microbiology which was opened by
Pasteur, Lister and Koch was perhaps the
greatest contribution ever to the theory
and practice of medicine.

Antonie van Leeuwenhoek in 1683
was the first to describe
microorganisms in human mouth.
-His astute observation on scrapings from
carious cavities in teeth were made with
the use of only a single-lens microscope.
- But despite such limitations he was able
to describe the principle shapes of bacteria
that remains the basis for much of the
classification of microorganisms today.
Microbiology in Dentistry

DEFINITIONS
. STERILISATION:
The process by which an article
surface or medium is freed of all
microorganisms, either in the vegetative
or spore state.
DISINFECTION:
The destruction of all pathogenic
micro organisms or organisms capable of
giving rise to infection.

ANTISEPTICS:
Chemical disinfectants, which
can be safely applied to skin or
mucous membrane surfaces and are
used to prevent infection by
inhibiting the growth of bacteria.
BACTERICIDAL AGENTS:
Agents able to kill bacteria.
BACTERIOSTATIC:
Agents preventing only the
multiplication of bacteria, which may
remain alive.www.indiandentalacademy.com

Goal of sterilization and infection control
Most microbes that we come in contact
do us no harm.
Others colonize and become established
as our commensal flora, yet others
establish infection.
Factors determining the development of
infectious disease
-virulence
-dose
-resistance
Health or disease=virulence x dose
-----------------------
resistance

Virulence of micro-organisms in their
natural environments cant be
changed
Resistance to diseases can be
enhanced by immunization but not
for all diseases
The only disease determinant we can
effectively manage is the dose, and
the management of the dose is called
as infection control.

INSTRUMENT PROCESSING
 Instrument processing is the
procedures that prepares contaminated
instruments for reuse. The processing
must be performed carefully so that
disease agents from a previous patient, or
from a member of the dental team who
handled the instruments, or from the
environment will not be transferred by
the instruments to the next patient.
Processing also must be performed
correctly to keep instrument damage to a
minimum.

Instrument processing steps
1. Holding (presoaking)
2. Precleaning.
3. Corrosion Control, Drying, Lubrication
4. Packaging
5. Sterilization
6. Sterilization monitoring
7. Handling Processed Instruments

I. HOLDING (PRESOAKING)
 This can facilitate the actual
cleaning.
 Extended presoaking for more than a
few hours is not recommended, for
this may enhance corrosion of some
instruments.
 The holding solution may be the
same as that to be used for ultrasonic
cleaning or it may be a germicidal
solution (e.g., a glutaraldehyde)
indicated for instrument immersion.
 If instruments cannot be cleaned
soon after use, place them in a
holding solution to prevent drying of

ii. PRECLEANING:
 Ultrasonic cleaning :
 Ultrasonic cleaning, compared with
scrubbing instruments by hand,
reduces direct handling of the
contaminated instruments and the
chances for cuts and punctures.
 Exception is some high-speed hand
pieces.
 The time required ranges from about
5 to 15 minutes.

Manual scrubbing of instruments
 Scrubbing contaminated instruments
by hand is a very effective method of
removing the debris if performed
properly.
 -All surfaces of all instruments
should be thoroughly brushed while
the instruments are submerged in a
cleaning solution to avoid spattering.
 -This is followed by thorough rinsing
with a minimum of splashing.

III. CORROSION CONTROL, DRYING,
AND LUBRICATION
 Instruments or portions of Instruments
and burs made of carbon steel will rust
during steam sterilization.
 Examples might be nonstainless steel
cutting or scraping Instruments such as
scalers, hoes, and the cutting surfaces of
orthodontic pliers.
 Although rust inhibitors (e. g., sodium
nitrite) that can be sprayed on the
Instruments will reduce rusting of some
of these items, the best approach is not to
process such items through steam.
 Instead, thoroughly dry the Instruments
and use dry heat or unsaturated chemical

IV :Packaging
 Packaging Instruments before
processing through the sterilizer
prevents them from becoming
contaminated after sterilization
during storage or when being
distributed to chairside. Packaging
involves organizing the Instruments
in functional sets and wrapping
them or placing them in
sterilization pouches, bags, trays,
or cassettes. www.indiandentalacademy.com

 Wrapping or Bagging :
 Functional sets of instruments can be
placed on a small sterilizable tray
and the entire tray wrapped with
sterilization wrap.Seal the wrap with
tape that will withstand the heat
process. (e.g., “autoclave tape”).

 Using Cassettes :
 Numerous styles of cassettes are
available that contain functional sets
of instruments during use at
chairside and during the ultrasonic
precleaning, rinsing, and sterilizing
processes.
 - Using cassettes reduces the direct
handling of contaminated
instruments and keeps the
instruments together through the
entire processing.www.indiandentalacademy.com

 Unwrapped Instruments :
 Sterilizing unpackaged instruments is
the least satisfactory approach to
patient protection because it allows
for unnecessary contamination
before the Instruments are actually
used on the next patient

METHODS OF STERILIZATION
1)Heat sterilization
2)Gas or ethylene oxide sterilization
3)Liquid chemical sterilization and
disinfection

HEAT STERILISAION
Heat sterilization is the most
common type of sterilization
technique used today.
Heat sterilization involves
a) Steam sterilization
b) Dry heat sterilization
c) Unsaturated chemical vapour
sterilization

Moist heat
 Temperatures below 1000C/
pasteurization
 Temperatures at 1000C/ boiling
 Steam at atmospheric pressure

Pasteurization ( below 1000C )
Purpose – To reduce the bacterial
population of a liquid such as milk
Spores are not affected by
pasteurization
 Holding method :- 62.90C for 30
min
 Flash pasteurization :- 71.60C for
15sec
0

 TEMPERATURE AT 100% C -
STERILIZER IN WHICH
INSTRUMENT ARE BOILED AT
100%C

Steam sterilization
 Steam under pressure has
a higher temperature than
100 C
 To be effective against
viruses and spore forming
bacteria it needs to have
steam in direct contact
with material
 Autoclaves are highly
effective and inexpensive

Characteristics :
 Temperature : 121 C (250 F)
 Pressure : 15 psi
 Cycle time: 15-20 minutes
 Acceptable Materials: Paper, plastic, cloth,
or paper peel pouches
 Unacceptable Materials: closed metal and
glass containers

dvantages:
Short efficient cycle time
Good penetration
Ability to process a wide range of materials
without destruction
isadvantages:
Unsuitable for heat sensitive objects
Corrosion of unprotected carbon steel
instruments
Dulling of unprotected cutting edges
Possibility that packages may remain wet at end
of cycle

Dry heat
DIRECT FLAME
Bunsen burner

Incineration

dry heat sterilization
Sterilization of
instruments with dry
heat is the least
expensive form of
heat sterilization. A
complete cycle
involves heating the
oven to the
appropriate
temperature and
maintaining that
temperature for a
proper interval. www.indiandentalacademy.com

Characteristics :
 Temperature :160 C (320 F) Or 170 C (340 F)
 Cycle time : 2 hours Or 1 hour
Requirements:
 Must not insulate items from heat
 Must not be destroyed by temperature used
Acceptable Materials: Paper bags, aluminum foil,
polyfilm plastic tubing
Unacceptable Materials : plastic and paper bags
that cannot withstand dry heat temperature

Advantages:
 -Is effective and safe for sterilization of
metal instruments and mirrors .
 -Does not dull cutting edges .
 -Does not rust or corrode
Disadvantages :
 -Requires long cycle for sterilization
 -Has poor penetration
 -May discolor and char fabric
 -Destroys heat-labile items
 -Cannot sterilize liquids
 -Is generally unsuitable for handpieceswww.indiandentalacademy.com

(iii) RAPID HEAT TRANSFER STERILIZATION :
Characteristics :
 Temperature : 190 C (375 F)
 Cycle time : 12 minutes for wrapped items ;
6 minutes for unwrapped items.
Acceptable Materials:
Paper bags, aluminum foil, polyfilm plastic
tubing
Unacceptable Materials :
Plastic and paper bags that cannot withstand
dry heat temperaturewww.indiandentalacademy.com

Advantages:
 -It has a shorter cycle time than regular dry
heat units.
 -Items are dry after cycle
 -It does not dull cutting edges
Disadvantages:
 -Instrument must be dried before packaging
and placement in chamber.
 -It destroys heat-labile items
 -It cannot sterilize liquids
 -It is generally unsuitable for dental
handpieces
 -Unwrapped items become contaminated
quickly after the cycle.

(c)Unsaturated chemical vapour sterilization
 Depends on heat, water and chemical
synergism for its efficacy
 A solution of alcohol, formaldehyde,
ketone, acetone and water is used to
produce a sterilizing vapour

Characteristics:
Temperature: 131 c
pressure: 20 psi
Cycle time: 20-40 mins
 Packaging material requirements :
Vapors must be allowed to precipitate on
contents
Plastics should not contact the sides of
sterilizer
 Acceptable materials: Perforated metal
trays, paper or paper peel pouches
 Unacceptable materials :solid metal trays
and sealed glass jarswww.indiandentalacademy.com

 Advantages:
-It has short cycle time
-it does not rust or corrode metal instruments
including carbon steels
-it does not dull cutting edge
-it is suitable for orthodontic stainless steel
wires
Disadvantages:
-Instruments must be dried completely
before processing
-A special chemical solution must be used
-It will destroy heat sensitive plastics
-There is a chemical odour in poorly
ventilated areas
-It can not steriize liquids:www.indiandentalacademy.com

GAS STERILIZATION

GAS STERILIZATION
Ethylene oxide: The use
of ETO is recognized by
the American Dental
association (ADA) and
Centers for Disease
control and prevention
(CDC) as an acceptable
method of sterilization
for the following items:

i) those that can be damaged by
heat and/ or moisture,
ii) and those that can be cleaned
and dried thoroughly..
This chemical is effective as a
virucidal agent, is sporicidal, does
not damage materials, and can
evaporate without residue

CHARACTERISTICS
Temperature : room temperature (250C/750F)
Cycle time : 10-16 hours (depending on
material)
Acceptable materials : paper, plastic bags
Unacceptable materials : sealed metal or
glass containers

Advantages:
-High capacity for penetration
-Does not damage heat-labile
material
-Evaporates without leaving a toxic
residue
-Suitable for materials that cannot be
exposed to moisture

Disadvantages:
-Slow, requires long cycle time
-Uses toxic/hazardous chemical
-Items must be cleaned and dried
thoroughly before exposure.
-Causes tissue irritation if not well
aerated

LIQUID CHEMICAL STERILIZATION
AND DISINFCTION
 Inexpensive and suitable for heat sensitive
items
 Toxic and irritant
 2% glutaraldehyde is most widely used,
Often used as disinfectants but can also
sterilize instruments if used for prolonged
periods
 liquid sporicidal chemical
 Most bacteria and viruses are killed within
10 minutes
 Spores can survive several hourswww.indiandentalacademy.com

RECENT ADVANCES
 Low temperature sterilization involves
vaporized H2O2
 Bead sterilizers
Size of glass beads – 1.2 to 1.5mm
Temperature - 4240 to 4500F
Time - 3 to 5sec
Disadv ; uneven temperatures
 Hot oil sterilization - mineral oil

Physical control
by
other methods

•FILTRATION
•ULTRASONIC LIGHT
•IONIZING RADIATION
•MICROWAVES
•LASERBEAMS

Selection of antiseptics & disinfectants
Prerequisites
 It should have a wide spectrum of activity
 Fast acting
 Active in the presence of organic matter
 Nontoxic to animals or humans ( antiseptic
)
 Soluble in water
 It should not separate on standing
 Should have high penetrating power
 Surface compatibility
 Relatively inexpensivewww.indiandentalacademy.com

Factors
 Concentration of the substance
 Time
 pH of the medium
 Temperature
 Nature of microorganism
 Surface to be treated
 Presence of extraneous material

Levels of disinfection
1. High - sterilizing agents
ex; ethylene oxide gas
2. Intermediate - bactericidal agents
ex; formaldehyde, alcohols
3. Low - narrowest anti-microbial
activity
ex; soaps, detergents

Mechanisms of anti-microbial action
 Agents that interfere with membrane
function
 Agents that denatures proteins
 Agents that destroy or modify the
functional groups of proteins

Agents that interfere with
membrane function
 Surface active agents
 Phenols
 Alcohols

Surface active agents
“Substances which alter energy
relationship at interfaces producing a
reduction of surface or interfacial tension”
 Anionic
 Cationic
 Nonionic
 Amphoteric

 Cationic detergents – quaternary
ammonium compounds
Ex; Acetyl trymethyl ammonium bromide
& Benzalkonium chloride
Disadvantages - Inability to penetrate
organic debris
- Incompatibility with
anionic agents

 Anionic detergents – Soaps &fatty
acids
 Nonionic detergents – Tween 80
relatively non toxic
 Amphoteric compounds – ‘TEGO’
compounds

Soap
– A chemical compound of
fatty acids combined with potassium or
sodium hydroxide
 pH - 8.0
 Mechanical removal of organisms
 Wetting agents
 Reduce surface tension

PHENOL DERIVATIVES
 CRESOLS - Greater germicidal activity &
lower toxicity
 BISPHENOLS - 2 phenol molecules
ex; Hexachlorophene, Chlorhexidine
FDA ( 1976 ) approved as a surgical scrub,
hand wash, superficial skin wound cleanser

Phenols and Derivatives :
 This phenolic solution was used as an all-purpose
surgical instrument immersion steriliant, hand
washing antiseptic, wound cleaner, and
preparatory antimicrobial for surgical sites...
 These agents act as cytoplasmic poisons by
penetrating and disrupting microbial cells walls,
leading to denaturation of intracellular proteins.
 The intense penetration capability of phenols is
probably the major factor associated with their
anti microbial activity .
 Thus, with the exception of the bisphenols, most
phenolic derivatives are used as disinfectants

ALCOHOLS
Effective skin antiseptics
 Ethyl alcohol - Denatures proteins and
dissolves lipids
- Dehydrating agent
Readily reacts with organic matter
 Isopropyl alcohol
 Methylalcohol

Alcohols:
- Ethyl alcohol and isopropyl alcohol have
been used extensively for many years as
skin antiseptics and surface disinfectants.
- Ethyl alcohol is relatively nontoxic, colorless,
nearly odorless and tasteless, and readily
evaporates without residue.
- Isopropyl alcohol is less corrosive than ethyl
alcohol because it is not oxidized as rapidly
to acetic acid and acetaldehyde.

Disadvantages :
-Not sporicidal
-Damaging to certain materials, including
rubber and plastic
-Rapid evaporation rate with diminished
activity against viruses in dried blood,
saliva, and other secretions on surfaces

Agents that denatures proteins
Ex; Acids
Alkalies
Alcohols
Acetone
Organic solvents

ACIDS & ALKALIES
Free H+ and OH- ions
Ex; benzoic acid, propionic acid
Acids are valuable adjuncts to
disinfection

Agents that destroy or modify the
functional groups of proteins
 Mercuric compounds – sulphydryl
groups
 Anionic detergents - amino &
imidazole groups
Ex; heavy metals
halogens
hydrogen peroxide

Heavy metals
‘An electron donating element
whose atoms are large, with complex
electron arrangements’
eg, mercury, copper, silver

Mercury (Hgcl2)
- Skin diseases
- Toxic to the host
- antimicrobial activity is reduced
in the presence of organic matter
Copper
- chlorophyll containing
organisms
- CuSO4 is a potent inhibitor of
algae

Silver - AgNO3
- antiseptic & disinfectant
- 1% AgNo3 solution is active against
Neisseria Gonorrhoeae infection
-used to disinfect suturing threads
-Not sporicidal

Halogens –
‘A group of highly reactive elements
whose atoms have 7 electrons in the outer
shell’
Chlorine – gasseous form, organic &
inorganic forms.
chlorine is available in 3 other forms
1. Hypochlorites
Organic chloramines
Inoganic chloramineswww.indiandentalacademy.com

Chlorine compounds
1.Ca(Ocl)2 - Chlorinated lime
2. NaOCl - DAKIN’s solution used to
treat ‘ATHLETE’s foot
3. Clorax & Purex bleach
4. Chloramines – Chloramine-T

Iodine and Iodophors :
 Iodine is one of the oldest antiseptics for
application onto skin, mucous membranes,
abrasions, and other wounds.
 high reactivity of this halogen with its target
substrate gives it potent germicidal effects.
 It acts by iodination of proteins and subsequent
formation of protein salts.
Tinctures of iodine are toxic for gram-positive and
gram-negative bacteria, tubercle bacilli, spores,
fungi, and most viruses.

Iodine
More reactive than chlorine
Halogenating tyrosine portions of protein
molecules
Tincture of iodine –2% iodine solution
in ethyl alcohol

- Iodophor antiseptics are useful in preparing
the oral mucosa for local anesthesia and
surgical procedures.
- Their surfactant properties make them
excellent cleaning agents before disinfection,
and newer iodophor commercial formulations
have shown EPA-approved tuberculocidal
activity within 5 to 10 minutes of exposure.

 Iodophors
‘Iodine detergent complexes that release
iodine over a long period of time’
Advantage – no staining of tissues or fabrics
Ex; wescodyne - preoperative skin
preparation
Betadine - presurgical scrubbing
Ioprep - local wound antiseptic

Hydrogen peroxide ( H2O2 )
 A simple chemical compound digested
by catalase to water and oxygen
 Mechanical removal of microorganisms
 New forms – super D H2O2

ALKYLATING AGENTS
 Formaldehyde
 Ethylene oxide
 Gluteraldehyde

Formaldehyde
Gas at high temperatures & a solid at room
temperatures
37% solution – Formalin
In gaseous form - Sterilize surgical equipment
& medical instruments
20% solution in 70% alcohol for 18hrs – to
sterilize instruments
-Causes Contact dermatitis

Ethylene oxide
 Toxic & Highly explosive
 Cold burns

Gluteraldehyde
 Activity will not reduce in the presence of
organic matter
 It does not damage delicate objects
 Irritating fumes
 Discoloration & corrosion of instruments

2.0 to 3.2% glutaraldehyde is used to sterilize
and disinfect. At these concentrations,
- glutaraldehydes can be effective against
vegetative bacteria, including M.
Tuberculosis, fungi and viruses, and can
destroy microbial spores after a 10-hour
immersion period..
- In fact, glutaraldehydes are useful in
decontaminating certain types of dental
impression materials.

Disadvantages :
- Although glutaraldehyde formulations are
effective as immersion steriliants/
disinfectants, they are also extremely toxic to
tissues.
- Irritation of hands and discoloration of
cuticles are common sequelae when people
do not wear appropriate utility gloves.
- damage to respiratory and olfactory tissues
and ocular injury

iii) Physical Monitoring :
 Physical monitoring of the sterilization
process involves observing the gauges and
displays on the sterilizer and recording the
sterilizing temperature, pressure and
exposure time.
 -It must be remembered that sterilizer
gauges and displays indicate the conditions
in the sterilizer chamber rather than
conditions within the packs, pouches or
cassettes being processed.
 -Thus, physical monitoring may not detect
problems resulting from overloading,
improper packaging material or use of
closed containerswww.indiandentalacademy.com

VII. HANDLING PROCESSED INSTRUMENTS :
 Instrument sterility should be maintained
until the sterilized packs, pouches or
cassettes are opened for use at chairside.
i) Drying and Cooling :
 Packs, pouches or cassettes processed
through steam sterilizer may be wet and
must be allowed to dry before handling

ii) Storage :
 Handling of sterile packages should be kept to a minimum ,
and those that are dropped on the floor, torn, compressed
or become wet must be considered as contaminated
 -Store sterile packages in dry, enclosed, low-dust areas
away from sinks and water pipes .This prevents packages
from becoming wet with splashed water.
 -And store the packages away from heat sources that may
make the packaging material brittle and more susceptible
to tearing or puncture.
iii) Distribution :
 Instruments from sterile packs or pouches can
be placed on sterile, disposable, or at least
cleaned and disinfected trays at chairside.
 -Sterilized instrument cassettes are distributed to
and opened at chairside

INSTRUMENT PROTECTION:
 Instrument processing can cause damage to
instruments, but several steps could be
taken to keep this at a minimum.
 Stainless-steel instruments are least
effected by corrosion from moisture and
heat, but some clinicians prefer instruments
with carbon steel rather than stainless-steel
cutting surfaces that may retain a sharp
edge longer.
 Unfortunately, carbon steel items corrode
and lose sharpness during sterilisation.
Carbon steel items are best sterilized in a
non-corrosion producing environment suchwww.indiandentalacademy.com

TO BE CONTINUED

Items Recommended covering
Chair back (optional) Plastic
Headrest (only if not covered along with chair back) Plastic
Dental unit, including hose supports Plastic
Side auxiliary support surfaces Plastic
Air-water syringe handle Plastic
High-volume evacuation control Plastic
Saliva ejector control Plastic
Lamp handles Foil, plastic wrap, or bag
Light communication system Plastic
Drawer handles Plastic

Systemic diseases with pathogens present in blood and other body
fluids
Disease Pathogen
Hepatitis B Hepatitis B virus
Hepatitis C Hepatitis C virus
Hepatitis D Hepatitis D virus
HIV-infection and AIDS Human immunodeficiency virus
BLOODBORNE PATHOGENS AND OTHER DISEASE AGENTS :
The patient’s mouth is the most important source of potentially
pathogenic microorganisms in the dental office. Pathogenic agents may
occur in the mouth as a result of four basic conditions:
Bloodborne diseases, Oral diseases, Systemic diseases with
oral lesions, and Respiratory diseases.

•Bloodborne pathogens may enter the mouth during
dental procedures that induce bleeding.
• Thus contact with saliva during such procedures
may result in exposure to these pathogens if present.
Because it is very difficult to determine if blood is
actually present in saliva, saliva from all dental
patients should be considered as potentially
infectious.

A B C D E
Other name Infectious Serum Parenterally
transmitted
non-A, non-
B
Delta Enterically
transmitted
non-A, non-
B
Major route
of
transmission
Fecal-oral,
water, food
Parenteral,
direct
contact
Parental,
direct
contact
Parental,
direct
contact
Fecal-oral,
water, food
Incubation 2-6 weeks 4-24 weeks 2-20 weeks 4-24 weeks Unknown
Liver
necrosis
Rare Uncommon Uncommon Yes Unknown
Chronicity No Yes
(5-10%)
Yes (50%) Yes No
VIRAL HEPATITIS

Risk for the dental team :
Risk for dental patients:
Hepatitis B vaccine:
•We are extremely fortunate that safe and effective vaccines
for hepatitis B are available.
•Because there is no successful medical treatment to cure this
disease, prevention is of paramount importance.
•The vaccine is strongly recommended for all members of the
dental team.
HEPATITIS B VIRUS

HIV INFECTION AND AIDS
Oral manifestations of AIDS :
Early manifestations of AIDS occur as oral lesions.
•Oral manifestations include fungal diseases, such as
candidiasis, histoplasmosis, geotrichosis, or cryptococcosis;
•viral diseases such as warts, hairy leukoplakia, or herpes
simplex infection;
• bacterial diseases such as rapidly progressing periodontitis or
gingivitis;
• cancerous disease such as Kaposi’s sarcoma and non-
Hodgkin’s lymphoma.
Transmission :
•Intimate sexual contact (vaginal, anal, oral) involving contact or exchange of
semen or vaginal secretions;
•Exposure to blood, blood-contaminated body fluids, or blood products;
•Perinatal contact (from infected mother to child

Exposure to blood :

Prevention :
Sexual contact :
Recommendations for preventing the spread of HIV-1 through
sexual contact includes abstinence or limiting sexual activities
to one partner who is not infected and who does not have any
other sex partners

-All members of the dental team and other health-care workers must
protect themselves from exposure to blood, saliva and other potentially
infectious body fluids.
- Contaminated sharps must be handled and disposed of properly.
-Gloves, mask, and protective eyewear and clothing must be used
during the care of all patients and in other instances to prevent direct or
indirect contact with body fluids.
- Also, all health-care workers must prevent their blood or body fluids
from coming into contact with the patients being treated, and instruments
and equipment used on more than one patient must be properly
decontaminated before reuse.
- Injection drug abusers must not use blood-contaminated needles.
Blood contact :

Diseases Pathogen
Herpes infections Herpesvirus hominis (herpes
simplex virus)
Syphilis Treponema pallidum
Hand-foot-mouth
disease
Coxsackievirus
Herpangina Coxsackievirus
Gonococcal
pharyngitis
Neisseria gonorrhoeae
Candidiasis Candida albicans
ORAL DISEASES

I) HERPES INFECTIONS :
Herpes simplex viruses may cause infections of the mouth, skin,
eyes and genitals.
-About 90% of adults have been infected with herpes simplex virus type
1, but only 10% (usually children) experience the typical symptoms of
oral herpes (primary herpetic gingivostomatitis).
-In this disease, vesicle-type lesions occur in the mouth.
-Vesicles during active herpes simplex infections at any site of the body
contain the virus which may be spread to others by direct contact with
these lesions.
-Also, the herpes simplex virus may be present in saliva in those with
oral or lip lesions and possibly in a small percent of those who are
infected but have no active lesions.
-In such instances, sprays or aeorosols of the saliva may result in
spread of the virus to unprotected eyes of the dental team.www.indiandentalacademy.com

II) HERPANGINA AND HAND-FOOT-MOUTH DISEASE :
Herpangina appears as vesicles on the soft palate or
elsewhere in the posterior part of the mouth that break down to
ulcers that last for about a week.
-Fever, sore throat and headache frequently accompany the
vesicular stage.
-The lesions are caused by specific types of coxackie virus.

III) ORAL SYPHILIS .
Treponema pallidum is a spirochete bacterium and is
the causative agent of syphilis.
-About 5-10% of the cases of syphilis first occur in the mouth
in the form of a lesion called a primary chancre, an open
ulcer frequently on the tongue or lips.
-These lesions do contain the live spirochetes and may be
spread by direct contact.
- The possibility of the spirochete entering small cuts or
breaks in the skin of unprotected hands of the dental team
exists and has been documented in one instance causing
syphilis of the finger.

IV) ORAL CANDIDIASIS :
Candida albicans is a yeast that occurs in the mouth
asymptomatically in about one third of adults.
-Such circumstances that may result in oral disease called thrush
or oral candidiasis might include conditions that disturb our body
defense mechanisms such as the systemic diseases of HIV
infection, and leukemia;
-Spread of C. albicans from a patient’s mouth to the dental team is
theoretically possible through direct contact with lesions or sprays
or aerosols of infected saliva.

IMMUNIZATION FOR ORAL HEALTH CARE PROVIDERS
Health care workers are at particular risk of several
vaccine-preventable diseases.

Generic name Primary schedule and Boosters (s)
Hepatitis B recombinant DNA Two doses IM 4 weeks apart, third dose 5
months after second
Rubella live virus vaccine One dose SC, no booster
Measles live virus vaccine One dose SC, no routine boosters
Mumps live virus vaccine One dose SC, no booster
Influenza vaccine (inactivated whole-
virus and split-virus vaccine) tetanus –
diptheria toxoid
Annual vaccination with current vaccine.
Either whole or split virus vaccine may
be used two doses IM 4 weeks apart,
third dose 6to 12 months after second
dose, booster every 10 years.
Enhanced – potency inactivated
poliovirus vaccine (E-IPV) live oral polio
virus vaccine (OPV)
E-IPV is preferred for primary
vaccination of adults, two doses SC 4 to 8
weeks apart, a third dose 6 to 12 months
after the second. For adults with a
completed primary series and for whom a
booster is indicated, either OPV or E-IPV
can be given
Recommended vaccines for Oral Health care Workers

PATHWAYS FOR CROSS-CONTAMINATION
A total office infection program is
designed to prevent or at least reduced
the spread of disease agents from:
•Patient to dental team;
•Dental team to patient;
•Patient to patient;
•Dental office to community, including the
dental team’s families.

i) Patient to Dental Team:
• Direct contact : with patient’s saliva or blood may lead to entrance
of microbes through a nonintact skin resulting from cuts, abrasions,
or dermatitis.
• Droplet infection: They occur as a result of sprays, spatter or
aerosols from patients mouth.
• Indirect contact: involves transfer of microorganisms from the
source (e.g., the patient’s mouth) to an item or surface and
subsequent contact with the contaminated item or surface.
• Examples include cuts or punctures with contaminated sharps (e.g.
instruments, needles, burs, files scalpel blades, wire) and entrance
through nonintact skin as a result of touching contaminated
instruments, surfaces or other item.

ii) Dental Team to Patient :
Spread of disease from the dental team to patients is
indeed a rare event, but could happen if proper procedures
are not followed.
-If the hands of dental team member contain lesions or
other nonintact skin.
- if the hands are injured while in the patient’s mouth,
bloodborne pathogens or other microbes could be
transferred by direct contact with the patient’s mouth, and
they may gain entrance through the patient’s mucous
membrane.
- If a member of the dental team bleeds on instruments or
other items that are then used in the patient’s mouth, cross
infection may result.

iii) Patient to patient :
Disease agents might be transferred from
patient to patient by indirect contact through
improperly prepared instruments, hand-
pieces and attachments or surfaces.

iv) Dental Office to Community :
This pathway may occur if microorganisms from the patient
contaminate items that are sent out or are transported away from the
office.
For example, contaminated impressions or appliances or equipment
needing service may in turn indirectly contaminate personnel or
surfaces in dental laboratories and repair centers. Dental laboratory
technicians have been occupationally infected with hepatitis B virus
(HBV).
This pathway also may occur if members of the dental team transport
microorganisms out of the office on contaminated clothing. In addition,
if a member of the dental team acquires an infectious disease at work,
the disease could be spread to personal contacts with others outside
the office.
Also, regulated waste that contains infectious agents and is
transported from the office may contaminate waste haulers if it is not in
proper containers.

PERSONAL PROTECTIVE EQUIPMENT AND BARRIER TECHNIQUES
Oral health care providers and their patients may be exposed to a
variety of microorganisms via blood or oral and respiratory secretions.
- Infections can be transmitted in the oral health care setting through
direct contact with blood, saliva, and other secretions ;
- Indirect contact with contaminated instruments, operatory equipment,
and environmental surfaces ;

Gloves : .
For the protection of oral health care personnel and the patient,
medical gloves always must be worn when there is a potential
for contacting blood, blood-contaminated saliva, or mucous
membranes.When asepsis is of prime concern wearing two pair
of gloves is recommended.since microorganisms multiply rapidly
in the environment under gloves, handwashes containing 4%
chlorhexidine are recommended.
.
.

 HANDWASHING AND CARE OF HANDS
BOTH CENTERS FOR DISEASE CONTROL AND
ADA

Masks :
When a tooth is cut with a high-speed turbine handpeice or
cleaned with an ultrasonic scaler, blood, saliva, and other
debris are atomized and expelled from the mouth.
-Masks that cover the mouth and nose reduce
inhalation of potentially infectious aerosol
particles.
-They also protect the mucous membranes of the
mouth and nose from direct contamination.
- Masks should be worn whenever aerosols or
spatter may be generated.

 MASK SHOULD FILTER

Protective eyeglasses :
During dental procedures, large particles of debris and saliva
can be ejected towards the oral health care provider’s face.
- These particles can contain large concentrations of bacteria
and can physically damage the eyes.
-Protective eyewear is indicated, not only to prevent physical
injury, but also to prevent infection.

 PROTECTIVE CLOTHINGs

DISPOSAL OR WASTE MATERIALS:-
- Gloves, masks, wipes, paper drapes:-
Handled with gloves, discarded in impervious plastic bags.
- Blood, disinfectants, sterilants:-
Carefully poured into a drain connected to a sanitary server
system.
- Sharp items, needles, blades, scalpels:-
Puncture- resistant containers marked with biohazard label.
- Human tissue:-
Same as sharp items, but diff. containers.

INFECTION CONTROL CONSIDERATIONS IN DENTAL OFFICE DESIGN
Additionally, the total square footage and layout of the entire
space should not be negotiated until each work area has
been evaluated. Considering that the clinical arena is the
most affected by infection control, the following elements
should be evaluated in regard to the overall health and
safety of the person performing the task.
1)Office flow
2)Cabinetry.
3)Laminate, wall, and floor coverings
4)Ventilation.

1) Office flow :
The layout of the entire office should incorporate a smooth efficient operational
flow. For example, patients have direct access to the treatment rooms and
consultation areas from the reception area without having to pass through
instrument processing areas.
2) Cabinetry :
The number of drawers and their contents should be minimized to simplify
cleanup procedures and reduce possible cross-contamination by the temptation
to reach into the drawer during a procedure.
-Treatment room cabinetry should be positioned on both sides of the patient’s
chair. This will allow both the doctor and assistant access to essential side
support areas and provide flexibility to both right and left-handed clinicians
working in the same space.

3)Laminates and wall and floor coverings :
Although patient appeal and aesthetics continue to be a consideration,
cabinetry surfaces and wall and floor coverings are a primary concern.
Wood surfaces, heavily textured wall coverings, and fabrics for decoration
should be eliminated. Smooth, seamless, nonporous materials will inhibit
the collection of microbes and, therefore, also should be considered.
4) Ventilation :
Work areas must have positive ventilation to control noxious vapors form
various chemicals used in laboratory and sterilization areas. Additionally,
considering that microbes inevitably are transported from one area to
another via ventilation systems, these systems must be designed to
prevent recirculation of contaminated air.

CONCLUSION
• IT IS OUR MOST IMPORTANT DUTY TO PRESERVE AND
MAINTAIN THE HEALTH OF OUR PATIENTS AND HIM SELF.
• WE AND OUR PATIENTS ARE AT ALARMINGLY HIGH RISK
OF GETTING INFECTED BY DANGEROUS DISEASES LIKE
Hepatitis-B, TB, Herpes, HIV ETC.
• TO PREVENT ALL THESE DEADLY DISEASES AND TO
PROTECT OURSELF WE SHOULD TAKE ATMOST
PRECAUTION BY FOLLOWING STRICT STERILISATION
AND DISINFECTION PROCEDURES.

• Bellavia De : Efficient and effective infection control. J Clin Orthod 1992; 26: 46-
54.
• Buckthal JE, Maynew MJ, Kusy RP : Survey of sterilization and disinfection
procedures. J Clin Orthod 1986; 20: 759-765.
• Cash RG : Trends in sterilization and disinfection, procedures in orthodontic
offices. Am J Orthod Dentofacial Orthop 1990; 98: 292-299.
• Cohen KL, Helen G : Disease prevention and oral health promotion.
• Compbell PM, Phenix N : Sterilization in orthodontic office. J Clin Orthod 1986;
20: 684-686.
• Cottone AJ : Practical infection control in dentistry.
• Council on Dental materials and council on dental therapeutics : Infection
control in dental office. J Am Dental Assoc 1978; 97: 673-677.
• Ascencio F, Langkamp H, Agarcoal S : Orthodontic marking pencils as a
potential source of cross contamination. J Clin Orthod 1998; 32: 307-310.

• Dental Clinics of North America (1991) : Infection control and office safety
• Dental Clinics of North America (1996) : Infectious diseases and dentistry.
• Dental Clinics of North America (July 2003) : Infections and infectious
diseases – Part I.
• Dental Clinics of North America (Oct 2003) : Infections and infectious
diseases – Part II.
• Drake DL : Optimizing orthodontic sterilization techniques. J Clin Orthod 1997;
31: 491-498.
• Jones M, Pizarro K, Blunden R : Effect of routine steam autoclaving on
orthodontic pliers. Eur J Orthod 1993; 15: 281-290.
• Lee SH, Chang Y : Effects of recycling on the mechanical properties and
surface topography of nickel-titanium alloy wires. Am J Orthod Dentofacial
Orthop 2001; 120: 654-663.
• Matasa CG : Orthodontic recycling at crossroads. J Clin Orthod 2003; 37: 133-
139.
• McCarthy GM, Mamandras AH, Mac Donald JK : Infection control in
orthodontic office in Canada. Am J Orthod Dentofacial Orthop 1997; 112: 275-
81. www.indiandentalacademy.com

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