Infection control in orthodontics

INFECTIONINFECTION
CONTROL INCONTROL IN
ORTHODONTICSORTHODONTICS
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INDEXINDEX
1.1. INTRODUCTIONINTRODUCTION
2.2. HISTORYHISTORY
3.3. BLOOD BORNE PATHOGENS AND DISEASE STATESBLOOD BORNE PATHOGENS AND DISEASE STATES
4.4. IMMUNISATION FOR ORAL HEALTH CARE PROVIDERSIMMUNISATION FOR ORAL HEALTH CARE PROVIDERS
5.5. PATHWAYS OF CROSS CONTAMINATIONPATHWAYS OF CROSS CONTAMINATION
6.6. INSTRUMENT PROCESSINGINSTRUMENT PROCESSING
7.7. STERILISATION METHODSSTERILISATION METHODS
8.8. PERSONAL PROTECTIVE EQUIPMENT AND BARRIERPERSONAL PROTECTIVE EQUIPMENT AND BARRIER
TECHNIQUETECHNIQUE
9.9. PROCEDURE FOR ORTHODONTIC INSTRUMENTSPROCEDURE FOR ORTHODONTIC INSTRUMENTS
10.10. DENTAL LAB INFECTION CONTROLDENTAL LAB INFECTION CONTROL
11.11. SURFACE ASEPSISSURFACE ASEPSIS
12.12. CONCLUSIONCONCLUSION
13.13. BIBLIOGRAPHYBIBLIOGRAPHY

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
population.
• Hepatitis-B, TB, Herpes simplex viral infections are well
recognised and indicate need for increased understanding of
modes of disease transmission and infection control
procedures by dental care providers.

•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. www.indiandentalacademy.comwww.indiandentalacademy.com

DEFINITIONSDEFINITIONS
. 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.

HISTORYHISTORY
 The science of microbiology has shed much light on the nature ofThe science of microbiology has shed much light on the nature of
disease. In the nineteenth century the work of Pasteur ,Lister anddisease. In the nineteenth century the work of Pasteur ,Lister and
Koch did much to explain the role of bacteria in disease and toKoch did much to explain the role of bacteria in disease and to
indicate possible methods of practicing safer medicine.indicate possible methods of practicing safer medicine.
 LOUIS PASTEUR (1822-95) was the first scientist to show clearlyLOUIS PASTEUR (1822-95) was the first scientist to show clearly
that bacteria never generate spontaneously and that no growth ofthat bacteria never generate spontaneously and that no growth of
any kind occurs in the sterilized media.any kind occurs in the sterilized media.
 One of his many achievements was the development of theOne of his many achievements was the development of the
technique of controlled heating known as ‘PASTEURISATION’ fortechnique of controlled heating known as ‘PASTEURISATION’ for
the preservation of beverages and food stuffs.the preservation of beverages and food stuffs.
 By his experimental studies on anthrax in 1876-77, for example, heBy his experimental studies on anthrax in 1876-77, for example, he
was to prove that a certain type of infection invariably occurredwas to prove that a certain type of infection invariably occurred
when a number of micro-organisms of a particular kind werewhen a number of micro-organisms of a particular kind were
introduced to the body..introduced to the body..

““If I had the honour of being a surgeon, impressed as IIf I had the honour of being a surgeon, impressed as I
amam
with the dangers of exposure to the microbes scatteredwith the dangers of exposure to the microbes scattered
of all objects, not only would I use perfectly cleanof all objects, not only would I use perfectly clean
instruments,but after washing my hands with greatestinstruments,but after washing my hands with greatest
carecare
and submitting them to rapid flaming, I would useand submitting them to rapid flaming, I would use
bandages,previously exposed in air at 130-150 degreebandages,previously exposed in air at 130-150 degree
andand
use water which has been submitted to a temp ofuse water which has been submitted to a temp of
120degree….this way I would have to fear only the120degree….this way I would have to fear only the
germsgerms
suspended in the air around the patients bed.”suspended in the air around the patients bed.”
Louis Pasteur(1878)Louis Pasteur(1878)

Dr. Joseph ListerDr. Joseph Lister ((1827-1912)1827-1912)
 Discovered the effectiveness of 'carbolic acid,‘ which wasDiscovered the effectiveness of 'carbolic acid,‘ which was
used in controlling typhoid.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 aCarbolic acid spray being used at the time of a
surgerysurgery

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

 Robert KochRobert Koch (1843-1910)(1843-1910) was undoubtedly one ofwas undoubtedly one of
the greatest figures in the development of microbiology.the greatest figures in the development of microbiology.
He had immense skill in devising new bacteriologicalHe had immense skill in devising new bacteriological
techniques. He was also the first to maketechniques. He was also the first to make
photomicrographs of stained smears, and in addition hephotomicrographs of stained smears, and in addition he
pioneered methods of growing bacteria on agar media.pioneered methods of growing bacteria on agar media.
 Despite the fact that the germ theory of disease hadDespite the fact that the germ theory of disease had
been established in 1877, it was not universally acceptedbeen established in 1877, it was not universally accepted
until 1882 when Koch presented his masterly paper onuntil 1882 when Koch presented his masterly paper on
‘The aetiology to tuberculosis’ giving details of the‘The aetiology to tuberculosis’ giving details of the
isolation of the tubercle bacillus. In the following year heisolation of the tubercle bacillus. In the following year he
isolated the cholera vibrio.isolated the cholera vibrio.
 The ‘Golden era’ of medical microbiology which wasThe ‘Golden era’ of medical microbiology which was
opened byopened by Pasteur, ListerPasteur, Lister andand KochKoch was perhaps thewas perhaps the
greatest contribution ever to the theory and practice ofgreatest contribution ever to the theory and practice of
medicine.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

Systemic diseases with pathogens present in blood and other bodySystemic diseases with pathogens present in blood and other body
fluidsfluids
DiseaseDisease PathogenPathogen
Hepatitis BHepatitis B Hepatitis B virusHepatitis B virus
Hepatitis CHepatitis C Hepatitis C virusHepatitis C virus
Hepatitis DHepatitis D Hepatitis D virusHepatitis D virus
HIV-infection and AIDSHIV-infection and AIDS Human immunodeficiency virusHuman 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.comwww.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.

After microbes enter the body, there are three basic factor that
determine if an infectious disease will develop:
•Virulence (pathogenic properties of the invading
microorganism);
•Dose (the number of microorganisms that invade the body);
•Resistance (body defense mechanism of the host).
These factors are called determinants of an infectious
disease, and their Interaction determines the outcome of an
infection as follows:
Disease= Virulence x Dose
Resistance
GOAL OF INFECTION CONTROL

OPERATORY
PREPARATION
AND
INSTRUMENT
RECIRCULATION

OPERATORY PREPARATION
General:
All surfaces and items touched by and contaminated with saliva or
blood, initially should be cleaned scrupulously and then
disinfected with an Environmental protection Agency (EPA)-
approved tuberculocidal agent before each patient is seated.
-An alternative is to use protective disposable covers.
-These barriers protect surfaces that directly or indirectly may
come into contact with body fluids.

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

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)
•If instruments cannot be cleaned soon after use, place them in a
holding solution to prevent drying of the saliva and blood.
•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.
• Place loose instruments in the ultrasonic cleaning basket and
then place the basket in the holding solution.

ii. PRECLEANING:
iii.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.
•This 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 vapor sterilization, which do not cause
rusting.

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.
Wrapping or Bagging :
Functional sets of instruments can be placed on a small sterilizable tray and the
entire tray wrapped with sterilization wrap grams the wrapping procedure. 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.
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.

STERILIZATION
1.Heat sterilization :Heat sterilization involving steam, dry
heat, and unsaturated chemical vapor is the most common
type of sterilization used in offices today. All the methods of
heat sterilization can be routinely monitored for
effectiveness using bacterial endospores
There are three types of sterilization processes used in
dentistry

Liquid chemical sterilization: Although the liquid chemical sterilant,
glutaraldehyde, can be shown to be sporicidal in controlled
laboratory testing,
Gas sterilization:
Ethylene oxide gas sterilizers that operate at 720F to 1400F (much
lower than heat sterilizers) also can be monitored with bacterial
endospores, but this type of sterilization is not commonly used in
dental offices because of the long exposure time required for
sterilization.

VI. STERILIZATION MONITORING :
-Heat sterilization failures result when direct contact
between the sterilization agent and all surfaces of
items being processed does not occur for the
appropriate length of time.
- In many instances, these failures will not be detected
unless proper sterilization monitoring is performed.
-There are three forms of sterilization monitoring,
biological, chemical and physical monitoring.

 Biological monitoring provides the main guarantee of
sterilization. It involves processing highly-resistant
bacterial spores through the sterilizer and then culturing
the spores to determine if they have been killed
 Types of biological indicators :
 Bacillus stearothermophilus - steam or chemical vapor
sterilization
 Bacillus subtilis - dry heat or ethylene oxide gas
sterilization.
i) Biological Monitoring

ii) Chemical Monitoring :
Chemical monitoring involves the use of indicators that change color or physical form
when exposed to certain temperatures such as autoclave tape, special markings on
pouches and bags, chemical indicator strips, tabs or packets or tubes of colored liquid.
Rapid-change indicator changes color rapidly after a certain temperature has been
reached (e.g., autoclave tape and special markings on pouches and bags). Used as an
external indicator on the outside of every pack

Slow-change or integrated indicator:
- that changes color or form slowly, responding to a combination of time and
temperature or temperature and the presence of steam.
-Used on the inside of every pack, pouch or cassette to assess if the
instruments have been exposed to sterilizing conditions.

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 containers.

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 such as dry heat or
chemical vapor sterilizer.

STERILIZATION METHODS :
PHYSICAL METHODS OF STERILIZATION :
The use of heat has long been recognized as the most
efficient, reliable method of sterilization.
(i) STEAM STERILIZATION :
Efficient sterilization may be
accomplished by the use of moist
heat at higher temperatures in the
form of saturated steam under
pressure. This modality remains
the oldest, most commonly used
of the acceptable methods for
instrument sterilization.

Characteristics :
 Temperature : 1210C (2500F)
 Pressure : 15 psi
 Cycle time : 15-20 minutes
 Acceptable Materials: Paper, plastic, cloth, or paper peel
pouches
 Unacceptable Materials : closed metal and glass containers
Advantages:
Short efficient cycle time
Good penetration
Ability to process a wide range of materials without destruction
Disadvantages:
Corrosion of unprotected carbon steel instruments
Dulling of unprotected cutting edges
Possibility that packages may remain wet at end of cycle
Possible deposits from use of hard water
Possible destruction of heat-sensitive materials

(ii) DRY HEAT :
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.
Characteristics :
Temperature : 1600C (3200F) Or 1700C (3400F)
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 handpieces

(iii) RAPID HEAT TRANSFER STERILIZATION :
Characteristics :
Temperature : 1900C (3750F)
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
temperature
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.

.
CHEMICAL 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, and
ii) 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 www.indiandentalacademy.comwww.indiandentalacademy.com

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
CHARACTERISTICS

GLUTERALDIHYDE:
(1.5-Pentanedial) (C5H8O2) has two aldehyde units, one at
end of the carbon chain. The later two types use an activator that
brings the final 2.0 to 3.2% glutaraldehyde to the desired pH. 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 sterilants/ 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.

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 plastics
-Rapid evaporation rate with diminished activity against
viruses in dried blood, saliva, and other secretions on
surfaces

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. solubilizing agent or carrier.

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.

Phenols and Derivatives :
• . This phenolic solution was used as an all-purpose surgical
instrument immersion sterilant, 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 primarily as disinfectants.

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.
.

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.

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.

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.

CONCLUSIONCONCLUSION
• 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.comwww.indiandentalacademy.com

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