sterilzation, asepsis and disinfection in orthodontic office

1. Sterilization, asepsis
and infection control in
orthodontics
Tanvi Andrade

2. Contents
Introduction
Terminologies
History
Methods of sterilization
Steps in infection control
Sterilization failure
Infection –types, spread.
Infection control in an orthodontic office
Conclusion
References

3. Introduction
The need for adequate sterilization cannot be overstressed. Although
various forms of sterilization have been implemented in orthodontic
offices, it has been pointed out that most protocols employed were
convenient adaptations that facilitated faster turnaround time and
orthodontic instrument longevity.
Matlack’s review of orthodontic offices confirmed this insufficiency.
Most orthodontic practices today see patients from a much broader age
group and socio-economic level. This means they are likelier to face
individuals who come into contact with drug and marijuana users, varied
sexual preferences and those getting medical treatment such as dialysis.
These people have a high risk of contracting infectious diseases eg
hepatitis, HIV. *Matlack : Instrument sterilization in orthodontic offices.
Angle Orthod. 1979 Jul;49(3):205-11

4. Terminologies
• DEATH (in microbiology):
irreversible loss of the ability to reproduce.
• STERILIZATION
The process by which an article, surface or medium is freed of
all living microorganisms either in the vegetative or spore state.
An object or substance can either be sterile or non-sterile; it
cannot be termed semisterile or almost sterile
• DISINFECTION
The destruction or removal of all pathogenic organisms, or
organisms capable of giving rise to infection

5. • ASEPSIS is the absence of infection or infectious materials or
agents.
• ANTISEPSIS is used to indicate the prevention of infection of
living tissues usually by inhibiting the growth of bacteria in
wounds or tissues.
• ANTISEPTICS chemical agents that can be used safely externally
on tissues to destroy microorganisms or to inhibit their growth.
• BACTERIOSTATIC - Agents which only prevent multiplication of
bacteria.
• BACTERICIDAL - Agents which are able to kill the bacteria
completely.

6. • BIOBURDEN:
The number and types of viable microorganisms that contaminate
the equipment/device.
•DECONTAMINATION refers to the process of rendering an article or
area free of danger from contaminants ,including microbial ,chemical
,radioactive and other hazards.
• BIOCIDE:
A substance that kills all living organisms
• INFECTION PREVENTION AND CONTROL:
Evidence-based practices and procedures that, when applied
consistently in health care settings, can prevent or reduce the risk
of transmission of microorganisms to health care workers, other
clients/patients and visitors.

7. History
Girolamo Fracastorius (Italian Physician) in 1546 was
credited as the first to recognize the existence of tiny
particles that cause contagious diseases spreading by
direct contact with human beings and animals and
indirect contact with objects.
Antoni van Leeuwenhoek first observed what he
called “animalcules” in 1667. The microorganism
became visible when he first observed tooth
scrapings and gutter water under a simple
microscope.
Ignaz Semmelewis (Austria) and Oliver Wendell
Holmes (United States) first recognized the
importance of hand washing to prevent the spread of
disease agents

8. Louis Pasteur and John Tyndall popularised
pasteurization destroying pathogens in milk
or other fluid by heating it to 63°C for 30
minutes or to 72°C for 15 seconds. This
method is still used today.
On August 9, 1867, Joseph Lister read a paper before
the British Medical Association in Dublin, on the
Antiseptic Principal of Plastic Surgery, which was
reprinted in The British Medical Journal.
He instructed surgeons under his responsibility to wear
clean gloves and wash their hands before and after
operations with 5% carbolic acid solutions.

9. Infection control agencies
• Centers for Disease Control & Prevention ( CDC )
• Food & Drug Administration ( FDA )
• Environmental Protection Agency ( EPA )
• Occupational Safety & Health Administration ( OSHA )

10. Methods of sterilization
PHYSICAL
• sunlight
• drying
• dry heat
• moist heat
• filtration
• radiation
• ultrasonic and sonic
vibrations
CHEMICAL
• alcohols
• aldehydes
• dyes
• halogens
• surface active agents
• metallic salts
• gases

11. • Appreciable bactericidal activity
• Spontaneous sterilization under natural
conditions.
• Due to ultraviolet and infrared rays
Sunlight

12. • Drying in air causes deleterious effects on many
bacteria.
• Spores are unaffected
• Hence very unreliable method.
Drying

13. • It is the most popular, reliable and widely used
method of sterilization
Two methods
• Dry heat
• Moist heat
Heat

14. • Nature of heat
• Temperature and time
• number of microorganism
• Characteristics of microorganism
• Type of material from which the microorganisms
have to be eradicated
Factors influencing
sterilization by heat

15. 1. FLAMING
• A simple & effective method
• Inoculating loops or wires, points of forceps and spatulas – heat
until red hot
• Scalpels, mouth of test tubes, glass slides, cover slips –should not be
allowed to heated until red hot
Dry heat

16. • Excellent method for rapidly destroying materials such as
Soiled dressing, animal carcasses, pathological material
• PVC and polythene can be dealt similarly
• Polystyrene materials should be autoclaved in appropriate
containers.
Incineration

17. Hot air oven
• This is the most widely used method
of sterilization by dry heat.
• Temperature – 160 c
• Cycle time – 1 hour
• useful for instruments that can be damaged by steam or
for materials that are impenetrable and unaffected by
steam.
• Used to sterilize – glass ware, forceps,
scissors, all glass syringes, scalpels,
liquid paraffin, dusting powder etc.

18. • Recently, more rapid dry heat sterilizers (COX sterilizers) have
become available; these can be operated at 187.7°C (370°F) for 6-,
8- or 12-minute cycles, depending upon the instruments and load.

19. Advantages:-
1.Is effective and safe for
sterilization of metal
instruments and mirrors.
2. Does not dull cutting
edges.
3. Does not rust or
corrode.
Disadvantages:-
1.Requires long cycle for
sterilization except for
forced air.
2.Has poor penetration.
3.May discolor and char
fabric.
4.Destroys heat labile items.
5.Cannot sterilize liquids.
6.Unsuitable for hand
pieces.
7.Cooling of the oven takes
a long time.

20. Glass bead sterilization
used to sterilize endodontic instruments
210c – 230c for 10-30 sec.

21. Moistheat
Below 1000 c
At 1000c
Boiling
Steam at atmospheric
pressure
Steam under pressure

22. Pasteurization
There are 3 methods :
Holder method
– It involves heating up to 630C for 30 min.
Flash pasteurization
-This method uses a temperature of 71.60 C for 15
sec.followed by cooling to 130C
Ultra pasteurization
- This method uses a temperature of 820 C for 3 sec.
Temperature below 1000C

23. • Non sporing bacteria are destroyed
• Media –Lowenstein –Jensen ,Loffler's serum –heating at 80-85 0c
for ½ hr on 3 successive days
• Heat resistant spores of clostridium botilinum-120 oc for 4 minutes
or 100 0c for 330 minutes
• Serum or body fluids can be sterilized by heating for 1 hr at 56 oc
on several successive days.

24. • Vegetative bacteria are killed immediately at 90 -
100 0 c
• Sporing bacteria requires prolonged periods
• Immerse the material in water and boil for 10- 30
minutes .
• Do not open the lid .
Boiling

25. • To sterilize culture media
• Koch or Arnold steamer.
• Exposure of 90 minutes is enough
• For medias with sugar /gelatin – exposure of 100 0c for 20
minutes on 3 successive days –TYNDALLISATION
• vegetative bacteria and spores are destroyed
• Fails to kill certain anaerobes and thermophiles
Steam under atmospheric
pressure

26. • Autoclave – “self locking”.
• Principle :
water boils when its vapor pressure = atmospheric pressure.
Pressure increases temperature increases
Steam contacts the cooler surfaces it condense
3 effects 1. wetting
2. liberate latent heat
3. significant contraction(1600 ml steam condenses to 1 ml
of water)
Steam under pressure

27. Parts of autoclave

28. • Parameters : 1210c -15 minutes at 15 psi
132 0c -3-7 minutes at 30 psi(unwrapped)
add 5 minutes for moderately wrapped packs
Recommended packing :
Wrapped in muslin cloth, paper,nylon,aluminium foil,
steam permeable plastic

29. Advantages:
1. Short efficient
cycle time.
2. Good
penetration.
3. Ability to process
a wide range of
materials.
Disadvantages:
1.Corrosion of
unprotected carbon
steel.
2.Dulling of unprotected
cutting edges.
3.Possibility that
packages may remain
wet at end of cycle.
4.Possible deposits from
use of hard water.
5.Possible destruction of
heat sensitive materials.

30. • Simple lab autoclave
• Transportable bench top autoclaves
• Large simple autoclaves
• Media preparators
• Multipurpose lab autoclaves
Types of autoclave

31. Filtration
Filtration helps to remove bacteria from heat labile liquids such
as sera and solutions of sugars or antibiotics used for preparation
of culture media.
Following types of filters are used-
1.Candle filters- Used for purification of water for industrial and
drinking purposes.
2.Asbestos filters-Are disposable, single use discs. They have high
adsorbing capacity and tend to alkalinize filtered liquids.

32. 3.Sintered glass filters- Are prepared by heat fusing finely powdered glass
particles of graded sizes. They have low absorptive property and can
be cleaned easily but are brittle and expensive.
4.Membrane filters- Routinely used in water purification and analysis,
sterilization
and sterility testing and for the preparation of solutions for parenteral
use.

33. Radiation
Two types of radiation are used for sterilization.
1. Non ionizing and
2. Ionizing.
Non ionizing - Infra red and UV rays.
Ionizing - Gamma rays and high energy
electrons.

34. Non-ionizing radiation
• Electromagnetic rays with longer wavelengths are used.
• Infra red radiation is considered as a form of hot air
sterilization.
• Infra red radiation is used for rapid mass sterilization of pre
packed items such as syringes and catheters.
• UV radiation is used for disinfecting enclosed areas such as
entryways, operation theatres and laboratories.

35. Ionizing radiation
• X- rays, gamma rays and cosmic rays are highly lethal to DNA
and other vital constituents.
• They have high penetrating power, since there is no
appreciable increase in temperature.
• this method is referred to as cold sterilization.
• Commercial plants use gamma radiation for sterilizing items
like plastics, syringes, swabs, catheters, animal feeds, oils,
greases, fabrics etc.

36. Ultrasonic and sonic vibration
• Ultrasonic and sonic waves are credited with bactericidal
powers but the results have been variable.
• Microorganisms vary in sensitivity to them, survivors are
found even after treatment.
• Hence it has no practical value in sterilization and disinfection.

37. • Alcohol
• Aldehydes
• Dyes
• Halogens
• Phenols
• Surface active agents
• Metallic salts
Chemical agents

38. IDEAL REQUIREMENTS of a chemical disinfectant
1. Broad spectrum
2. Fast acting
3. Non toxic
4. Surface compatibility
5. Should not corrode instruments and other metallic
surfaces and cause disintegration of cloth, rubber or
other materials

39. 6. Easy to use
7. Odourless
8. Economical
9. Be stable
10. High penetrating power
11. Should not cause local irritation and sensitivity
12. High solubility
13. Should be soluble in water and have a substantial shelf life

40. • Concentration of the substance
• Time of action
• pH of the medium
• Temperature
• Nature of organism
• Presence of extraneous material
Factors determining potency of
agents

41. Effective skin antiseptics and valuable disinfectants for medical
instruments.
Ethyl and isopropyl alcohol are most frequently used
Isopropyl alcohol is preferred to ethyl alcohol as it is a better fat
solvent ,more bactericidal and less volatile
It is active against vegetative bacterial cells, including the tubercle
bacillus,
Action:It denatures proteins & lipids, and leads to cell membrane
disintegration
It is also a strong dehydrating agent.
It is used to sterilize the skin prior to cutaneous injections .
Alcohol

42. • Formaldehyde
• Action : against amino group in the protein molecule
• It is available as solution and formaldehyde gas
• Sporicidal and bactericidal
• Lethal on viruses
• To preserve anatomic specimens,10% formalin with
0.5% sodium tetraborate – clean metal instruments
formalin
• To sterilize instruments and heat sensitive catheters
• fumigation
gas
Aldehydes

43. Gluteraldehyde
• Similar to formaldehyde
• Effective against tubercle bacilli,fungi
,viruses
• Less toxic
• Used to treat corrugated rubber
anesthetic tubes and face masks,
plastic endotracheal tubes and metal
instruments

44. Chemiclave
• By Dr. Hollenbeck & Harvey in 1940
• Uses- alcohols, acetone and formaldehyde
Advantages
Not corrosive
Load comes out
dry
Relatively quick
Disadvantages
Offensive odor
Cost
Adequate
ventilation is must

45. Aniline dyes
• Brilliant
green,malachite
green,crystal violet
• Act more on gram
positive bacteria
• Action : reacts with
acid groups in the
cells
Acridine dyes
• More active against
gram positive
bacteria
• Action : impair DNA
complex
Dyes

46. • Iodine :
Aqueous and alcoholic solution
Skin disinfectant
Actively bactericidal,moderate action against spores.
Active against tubercle bacilli,viruses
Iodophores are active than iodine
Halogens

47. • Chlorine
• bactericidal; wide spread action against viruses
• Used in disinfection of swimming pools ,food and dairy products

48. • Lister introduced them in surgery
• Powerful microbicidal
• Eg: lysol ,cresols
 Actions : 1.cause damage to cell membrane
2.release cell contents and cause lysis
3.precipitate proteins
4.membrane bound oxidases and
dehydrogenase are in activated
Chlorophenols and chloroxyphenols – in surgical and neonatal
units in hospitals
Chlorhexidine – skin antiseptic active against gram positive
bacteria
Phenols (carbolic acid)

49. • Ethylene oxide:
• It diffuses readily through porous materials
• Used for sterilisation of heart lung
machines,respirators,sutures,books,dental
equipment,clothing.
• Action:1. alkylation of amino group, carboxyl group, sulphydryl
group in protein molecule.
2.reacts with RNA and DNA(mutagenic)
3. Effective against viruses and spores
Gases

50. • Formaldehyde gas:
• fumigation of operation theatre
• Betapropiolactone :
• It is a condensation product of ketane and formaldehyde with a
boiling point of 163 0 c
• 0.2% BPL is used
• Used in fumigation
• Rapid biocidal action,but carcinogenic

51. • Widely used as: wetting agent,detergents,emulsifiers.
Surface
active agents
Cationic
agents
Anionic
agents
Non ionic
Amphoteric
agents
Surface active agents

52. Cationic agents
• Actions : acts on the phosphate groups of the cell membrane
and enter cell
loss of cell permeability and protein
denaturation
• Available as quaternary ammonium compounds
• bactericidal ; active against gram positive bacteria
• No action on spores ,tubercle bacilli , most viruses.
• Common compounds: acetyl trimethyl ammonium
bromide,benzalkonium chloride

53. • Anionic agents:
Common soaps
• Amphoteric agents :
Acts against both gram positive and gram negative bacteria and
viruses

54. • Germicidal action
• Depends on concentration
• Salts of silver, copper, mercury are used
• Action : protein coagulation ,combine with the
sulphydryl groups of cell enzymes
• Copper salts are excellent fungicides
Metallic salts

55. Steps in comprehensive infection control
protocol
• Patient evaluation
• Personal protection of dental team by immunizations
• Personal protective equipment
• Hand care
• Disposal of waste

56. Patient evaluation
•Thorough medical history
•Will help minimize cross infections

57. Immunization
• All health care workers must be encouraged to seek
an early diagnosis and treatment of a seemingly
minor condition
• The Center for disease control and prevention (CDC)
has recommended antiviral drug treatment for
health care workers exposed occupationally to HIV so
as to reduce the risk of infection.

58. • The immunization schedule for infants and
children includes protection against
poliomyelitis, diphtheria, tetanus, pertusis,
MMR, influenza, hepatitis B
• Each agent requires a booster dose
Eg: tetanus boosters of 10 yrs or when an injury
occurs

59. • The Advisory Committee on Immunization Practices (ACIP):
1. Tetanus and diphtheria – 3 doses: 1 every 10 yrs.
2. Influenza – 1 dose annually
3. Pneumococcal – 1 dose
4. Hepatitis B – 3 doses(0, 1-2, 4-6 months)
5. MMR – 1 dose
6. Varicella – 2 doses
7. Meningococcal – 1 dose
8. Annual tuberculin tests
9. Frequent throat cultures

61. Universal precautions
• Blood and certain body fluids of all
patients are considered potentially
infectious
• Universal precautions include use of
gloves, gowns, aprons, masks, protective
eye wear
• Precautions to prevent injuries caused by
needles, scalpels and sharps

62. • Protective barriers, now commonly referred to as
personal protective equipment (PPE).
• Gloves
• Face masks and shields
• Protective eyewear
• Gowns
• Head covers
Personal protective equipment

63. • Prevent direct contact with microorganisms in
the patients oral cavity and other contaminated
surfaces
• Also useful while handling chemicals
• Various types and sizes are available
Gloves

64. • Based on use

65. Removal of gloves

66. • Protect the mucous membranes of nose and mouth from
contact with sprays ,spatter of oral fluids from patients fluids
• Protection from inhalation of aerosols
• Made of synthetic material
• Shapes:
Masks

67. • Protection against infectious diseases through sprays,
splatter or aerosols
• Physical damage to eyes
• Impact damage to eyes
Protective eyewear

68. • To protect the underlying work
clothes ,skin from contamination
• Must be changed regularly
• Head covers are also appropriately
used
Protective covering

69. Head covers
Surgeon Hood And Head
Cover
Bouffant Cap
• Wear head covers to protect the hair and
scalp from possible contamination when
sprays or airborne exposure is anticipated.
• Head covers can be worn as part of Full
Barrier Precautions

70. Putting on and removing the
barriers
• Putting on
• Removing
Protective
clothing
Protective
eyewear
Mask gloves
Disposable
gown
gloves eyewear mask

71. Instrument processing in a
dental office
• Classification of chemical disinfectants was proposed by
Earle Spaulding in 1972
• It was originally developed for classifying hospital
instruments but now has been modified for dental
instruments.

72. Critical penetrates soft tissue
or bone, or enter into or
contact the bloodstream
or other normally sterile
tissue
Needles, scalpels,
surgical
instruments,
scalers, surgical
dental burs,
dental explorers.
steam under pressure
(autoclaving), dry heat, or
heat/chemical vapor.
Semi critical Contacts mucous
membrane but
not penetrate soft
tissues or bone or enter
into or contact the
bloodstream or other
normally sterile tissue
dental mouth
mirrors, reusable
impression trays
and amalgam
condensers.
high-level disinfection
Noncritical contacts only intact skin Counter tops,
light handles,
chair surfaces.
x-ray heads,
blood pressure
cuffs
An intermediate-level
disinfectant (if blood is
visible)or low-level
disinfectant (if no blood is
visible)
Category Definition Examples Level of Decontamination

73. ` Is the item
disposable ?
yes
discard
no
Can it be covered
?
No
Is it heat stable ?
Yes
Package and heat
sterilize
no
Sterilize in liquid
sterilant,
yes
Cover to prevent
contamination

74. Holding Precleaning
Corrosion
Control,drying
,Lubrication
PackagingSterilisation
Handling
Processed
Instruments
Cycle in instrument processing

75. Holding

76. • Reduces the bio -burden
Types
Ultrasonic
cleaner
Instrument
washer
Pre-cleaning

77. • Mechanism
• advantages: reduces direct handling
excellent cleaning mechanism
• Features
• Available in several sizes
• May have automatic drains
• Can process instruments as loose or in cassettes
• Operate with a cover
• Use recommended cleaning solution
• Process until its visibly clean
Ultrasonic cleaner

79. • Time taken : 4- 16 minutes
• It depends on various factors
• After cleaning remove the basket ,rinse under tap
with minimum of splashing
• Drain the solution at least daily
• Rinse ,disinfect the chamber
• Testing of ultrasonic unit(aluminium foil test)

81. • Used in hospitals , dental schools , and some dental clinics.
• Similar to ultrasonic washer
• FDA regulated
• Automatically provides cleaning and rinsing
• Also disinfect
• 3 models are available
Instrument washer

82. • Dangerous ,but effective
• Brush all surface
• Use long handled brush
• Not much recommended
Manual scrubbing

83. • Use dry air or unsaturated chemical vapors
for sterilization .
• Hinged instruments are to be lubricated
• Use anti rust spray or solution
Corrosion control, drying, and
lubrication

84. • It involves organizing the cleaned
instruments in functional sets and
wrapping in sterilizing pouches
,bags ,trays , or cassettes
• This aids in delivering sterile
instruments at the chair side.
PACKAGING
• Place the sets of instrument on a
small sterilizable tray and wrap
entire tray with sterilization wrap
• Seal the wrap with a tape
• Paper –plastic pouches, nylon type
,paper bags can also be used
• Use of instrument cassettes
WRAPPING

86. • Packs processed after steam
sterilization must be dried.Drying
• To avoid formation of condensation on
instrumentscooling
• Away from sink ,sewer ,water pipes,
ceilings,
• dry, enclosed ,low dust area
• Maximum storage -1 month
storage
Handling of processed
instruments

87. OSHA’S REGULATIONS
• HIV and hepatitis patients cannot be refused dental or
OMFS treatment.
• Universal barrier techniques are mandatory.
• Instruments must be both cleaned and sterilized
between patients.
• Environmental disinfection must be performed
• Infectious waste disposal must follow specific
guidelines.
• Training records in infection control must be kept for
each employee.

88. • The surfaces of dental units may accumulate
infective material. When selecting equipment,
consideration should be given to the ease with
which it can be cleaned and disinfected.
Surface asepsis

89. • There are 2 general approaches to surface
asepsis:
a) prevent the surface or item from becoming
contaminated by use of a surface cover.
b) preclean and disinfect the surface after
contamination and before reuse.

90. Surfaces which are susceptible to contamination

91. • Surface Covers:
- the best way to manage surface asepsis.
- it should be impervious to fluids
- examples are Clear plastic wrap, bags or tubes,
plastic-backed paper & Aluminum foils.
- some plastics are specifically designed such that
they have the shape of the item to be covered.
- thin plastic sheets may be used to cover flat
operatory surfaces.

94. • Precleaning & Disinfection
This is best done on surfaces that are smooth
and easily accessible for facilitating good contact
with the decontaminating chemicals.
- surfaces must be precleaned prior to disinfection.
- this helps in reducing the number of contaminating
microbes and the blood or saliva present & also
facilitates the action of the disinfecting chemical.

95. Spray
Wipe
Spray
Spray wipe technique

96. • One should spray disinfectant on precleaned surface and let it
remain moist for longest contact time (10 minutes)
• If moisture remains ,remove with a towel
• If it needs to be used in patients mouth ,rinse and dry it
Disinfection

97. • High level disinfection – these disinfectants must inactivate resistant bacterial
spores and all other microbial forms E.g. ethylene oxide gas, immersion
gluteraldehyde solutions
• Intermediate level disinfection– these disinfectants do not inactivate spores
during routine use but they destroy other forms of microbes E.g. formaldehyde,
chlorine compounds, iodophors, alcohols, phenolic compounds
• Low level disinfectants - provide the narrowest antimicrobial range E.g.
quaternary ammonium compounds, simple phenols and detergents
• Such compounds are suitable for cleaning environmental surfaces
CDC categorised disinfectants

98. • Research has shown that in newly installed dental unit
waterlines, microbial counts can reach a count of
200,000 colony-forming units per millilitre (CFU/mL)
within five days.
• Bacteria and other microorganisms form a biofilm, which
adheres to the inside of the tubing that supplies water to
the dental instruments.
• As water moves through the tubing, or waterline,
microorganisms slough off into the water, thus
contaminating it.
DENTAL UNIT WATER LINE ASEPSIS(DUWL)

99. Guidelines for Properly Treating Dental Unit Waterlines
• Follow current ADA and CDC recommendations
to flush handpiece hoses and air/water syringes
for 20-30 seconds between patients.
• If recommended by the dental unit
manufacturer, install and maintain anti
retraction valves to prevent oral fluids from
being drawn into dental waterlines.
• Do not heat dental unit water. Warming the
water promotes biofilm formation.
• Separate reservoirs, chemical treatment
protocols, and sterile water delivery systems.
• Use sterile solutions for all surgical irrigations.

101. Hand care
• Hands serve as a means of
transmission of blood, saliva, dental
biofilm
• Finger nails serve as a reservoir for
micoorganisms
• Skin breaks serve as a port of entry

102. •Maintain clean, smoothly trimmed,
short finger nails
•Remove hand and wrist jewellary
•Never expose open skin lesions or
abrasions to patients oral fluids or
tissues
•After glove removal, wash hands
thoroughly

103. When do you perform Hand Hygiene
There are 4 moments when hand
hygiene is performed.

104. Efficacyof Hand Hygiene Preparationsin Killing
Bacteria
GOOD BETTER BEST
PLAIN
SOAP
AND
WATER
ANTIMICROBIAL
SOLUTION AND
WATER
ALCOHOL
BASED HAND
RUB
.

106. WHO Recommended Hand Hygiene
Technique

107. Waste disposal
• Ministry of Environment and Forests (MoEF),
Govt. of India, Framed a rule known as ‘Bio-
medical Waste (Management and Handling)
Rules, 1998’
• “Any waste, which is generated during the
diagnosis, treatment or immunization of human
beings or animals or in research activities
pertaining there to or in the production of
testing of biological”

109. Waste Categories Description and Examples
1.General Waste No risk to human health eg:office
paper,wrapper,kitchen waste,general
sweeping etc.
2.Pathological Waste Human Tissue or fluid eg:body
parts,blood,body fluids etc.
3.Sharps Sharp waste
eg:Needle,scaples,knives,blades etc.
4.Infectious waste Which may transmit bacterial,viral or
parasitica disease to human being,waste
suspected to contain pathogen
eg:labrotory
culture,tissues(swabs)bandage etc.
5.Chemical waste Eg: Laboratory reagent, disinfectants,
Film Developer
6.Radio-active waste Eg: unused liquid from radiotherapy or
lab research, etc.
7.Pharmacutical Waste Expired outdated drugs /chemicals
8.Pressurized container Gas cylinder, aerosal cans etc
9.Genotoxic Waste Waste Containing Cytotoxic Drugs(often
Used In Cancer Therapy)

112. Sterilization
monitoring
Mechanical/Digital
Monitoring.
Chemical
Indicators.
Biological
Monitoring

113. • Biological indicators (BI) test the ability of
the sterilization cycle to kill resistant
microorganisms in a given sterilizer at a
given time
• The spores of a clostridium tetani or bacillus
subtilis - dry heat sterilization
steam autoclaves and chemiclaves, -
Geobacillus stearothermophilus
• Paper strips impregnated with 10⁶ spores are
placed in envelopes and inserted into
suitable packs.
• After sterilization, strips are inoculated into
media and incubated
Biological
indicators

115. Chemical Indicators
Both external
and
intergrated
chemical
indicators are
available
Chemical
indicators
consist of
heat- or
chemical-
sensitive ink
impregnated
on to an
indicator strip
or tape.
They may be
autoclave
tapes,
strips,tubes of
colored
liquids
The internal
indicator -
placed inside
the packaging
among the
instruments
The external
indicator
should be
placed on the
external
surface of the
packaging.

117. • MECHANICAL/DIGITAL MONITORING
• Mechanical (analog) monitoring involves the use of
time, temperature and pressure gauges that can be
viewed to verify these parameters.
• Gauge displays on sterilizers must be monitored for
cycle times, temperature and pressure during
sterilization.
• Many current sterilizers have digital readings, which are
more reliable than mechanical controls.
• Many autoclaves now also provide printouts of
temperature, the time at the temperature, and
pressure measurements during the sterilization cycle.

118. SPORE TESTING
• Once per week
• After training of new sterilization personnel/staff
• Whenever a new type of Packaging material or loading
tray is used
• During initial use of a new sterilizer
• First run after repair
• With every implantable device until results of test are
known
• After any other change in sterilization procedure

119. IMPROPER CLEANING
• Debris may
insulate
organisms
from direct
contact with
sterilizing
agent.
IMPROPER
PACKAGING
Use of wrong
packaging material,
or
Excessive packaging
material or cloth
wrap(may absorb
chemicals) in chemical
vapor sterilizer
IMPROPER LOADING
• Overloading
(increases heat up
time) or
• no separation
between packages or
cassettes even
without overloading
may prevent or retard
thorough sterilizing
agent with all items in
the chamber.
Sterilization failure

120. IMPROPER TIMING
• Incorrect
operation of the
sterilizer timing for
sterilization
• dry heat sterilizers
opened during
sterilizing cycle
without starting
cycle over or
• sterilizer timer
malfunction
IMPROPER
TEMPERATURE
• Incorrect
operation of the
sterilizer or
sterilizer
malfunction
IMPROPER METHOD
• Solutions or water
processed in a
chemical vapor
sterilizer will not
penetrate the solution
• Solutions or water
processed in a dry heat
sterilizer will boil over
and evaporate
• Processing of heat
sensitive item (e.g.
some plastics ) will
melt or distroted

121. Why infection control?

122. • Infection control involves 2 basic
factors
1. Prevention of spread of
microorganisms from their hosts
2. Killing and removal of
microorganisms from objects and
surfaces.

123. • Infection through any of the routes requires
the following
1. Susceptible host
2. Pathogen with sufficient infectivity and
numbers to cause infection
3. Portal through which the pathogen enters the
host

124. Objectives of infection control
• Reducing the no. of pathogens
• Breaking the cycle of infection
• Eliminating cross contamination
• Treating every patient and instrument as a
potential source of transmitting infection

125. Types of infection
•Autogenous infections
•Cross infections.

126. Autogenous infections
• Are those caused by microbes that the patient carries on or in
his or her own body.
• Many of the procedures in dentistry are invasive and open the
tissues to infections by micro organisms. These microbes
usually are harmless within the oral cavity, but may cause
disease if they enter the tissues.
Eg: infective endocarditis, oral abscesses.

127. • Many autogenous infections can be prevented by preoperative
prophylactic therapy.
Eg: endocarditis is prevented by the use of antibiotics.
frequency of abscesses may be reduced by applying an
antiseptic such as iodophor, to the mucous membrane

128. Cross infections
• Are caused by infectious agents that are transmitted among
dental personnel, patient and the environment.
• The transfer of disease may be from dentist to patient or vice
versa.
Eg: hepatitis B is an occupational hazard for dental personnel

129. Pathways of cross-infection
•Patient to practitioner
•Practitioner to patient
•Patient to patient
•Clinic to community
•Clinic to practitioners family
•Community to patient.

130. Saliva/blood of patient – non intact skin.
Infectious skin lesions of patient to non intact
skin
Sprays ,spatter ,aerosols – non intact skin or
inhalation
Microorganisms from patients mouth –item or
surface –contact with dental team.
Injury with contaminated sharps
Patient to dental team

131. Direct
•Dental
team
lesions
or
bleeding
Indirect
•Bleeding
on items
used in
patients
mouth
Droplet
•From
infected
droplets
Dental team to patient

132. • Transmission of HSV
• From infected individual to dental team or contaminated
instruments and then to other patients
• Usually from improperly sterilized instruments, contaminated
surfaces, handpieces,infected hands etc
Patient to patient

133. • Contaminated impressions /appliances etc- contaminate
personnel or surface in the dental laboratories
Dental office to community

134. • Mainly through the dental water supply units
• The microorganisms colonize the dental unit water line and
form biofilms
• As water flows through the lines during the use of air way
syringe or high speed handpiece it picks up microorganisms
shed by the biofilm
Community to patient

135. Factors affecting infection transmission
1. Source of infection: it may be a patient or a
member of dental team
2. Means of transmission: microorganisms capable
of causing disease are present in human blood.
These microorganisms must be present over a
certain concentration within blood or saliva to
overcome the body’s defenses. This is known as
minimum infective dose.

136. 3. Route of transmission:
Microbial transmission by dental related secretions
occur by 2 routes
a. innoculation- direct contact of previously
damaged skin or mucous membrane with a
lesion, organism or debris while performing
intraoral procedures, provides a portal of entry.
Accidental self injury with a contaminated
needle, sharp instruments or flying debris from
oral cavity provides second portal of entry.
eg: hepatitis virus, HSV, HIV

137. • Inhalation- occurs when using high speed or
ultrasonic equipment. Potential danger is often
missed since splatter coming from patients
mouth are not always noticed
Eg: CMV, Rubella, Mumps, S.pyogens.

138. 4. Susceptiblehost
• Susceptible host is a person who lacks effective
resistance to particular pathogenic microorganisms.
• Factors that increase the risk and severity are-
1.Medications such as steroids
2.Immunization status
3.Chemotherapy
4.Underlying disease such as diabetes.
5.Nutritional status
6.Heredity

139. INFECTIOUSAGENTSAND THEIRROUTESOF
TRANSMISSION
VIRUSES
inhalation
Cytomegalo virus
Measels
Mumps
Influenza virus
rubella
innoculation
Hep B, C
Herpes simplex
HIV

140. Bacteria
• Neisseria gonorrhoeae Inoculation
• Treponema pallidum Inoculation
• Mycobacterium tuberculosis Inoculation/Inhalation
• Streptococcus pyogens Inhalation

141. Infection control in an
orthodontic office
• Orthodontists do not perform oral surgery, but
come in direct contact with blood and oral fluids
of healthy patients or patients with infectious
diseases when placing or removing fixed
appliances.
(Toroglu et al., 2001)

143. Environmental safety
co-ordinator
• One personnel of the office should be appointed as
“environmental safety co-ordinator”
• His/her responsibilities include
1. Conducting staff training annually or as procedures change
2. Keeping records of Hep-B vaccinations of all employees
3. Coducting and documenting weekly spore tests and other
monitoring
4. Maintaining inventory
5. Cleaning daily, weekly or monthly as required
6. Recording exposure-incident reports

144. • A well-planned and designated area in the clinic setting
• Facilitates a sequenced and scheduled sterilization protocol
• Pre-alloted disinfection and storage areas should be
demarcated

145. Alginate impressions
• Commonly used disinfecting solutions are 2% glutaraldehyde
and 1% sodium hypochlorite.
1. Rinse the impression under running water on removal from
the oral cavity.
2. Immerse them in disinfecting solution for 7-8 minutes (not
more than 10 minutes)
3. Clean under running water to remove the disinfecting
solution.
4. Pour the model.

146. Gypsum casts
• Preferable to disinfect the impression
• Can be sprayed with iodophors
• Followed by rinsing
• Or
• Soak casts in a 0.5% concentration of sodium hypochlorite

147. Sterilization of orthodontic
pliers
• Orthodontic instruments used regularly have hinges and
cutting edges, and this makes disinfection prior to
sterilization a sensitive procedure
• Instruments have to be cleaned and dried prior to
sterilization in order to minimize damage and corrosion
when applicable, and to increase lifespan.
• Corrosion can be prevented by oiling the joint surfaces
with appropriate solutions
Holht et al., 1998).
(Haydar, 2000).

148. • Mazzochi in 1996:
• evaluated the effects of autoclaving, dry-heat and chemical
sterilization for 500 cycle’s usage, on hardness, degradation
and nitrification in the surface color.
• The maximum increase in hardness was observed when the
autoclave was used, and the least amount when dry-heat
sterilization was used.
• Degradation in the surface color was observed in each group
but mostly when the chemical sterilization was used.

149. • Wichelhaus et al in 2004:
• evaluated corrosion resistances of orthodontic pliers after
chemical sterilization with surface disinfectants.
• They concluded that dry-heat sterilization does not corrode
the instruments as much as chemical sterilization
• spray disinfection was found to be insufficient for reducing the
amount of the microorganisms
• Successful results can be achieved from thermal disinfection

150. Procedure
• Ultrasnic cycle for 5 to 12 minutes
• Rinse with distilled water
• Dry with compressed air(oil-free)
• Lubricate joints and cutting surfaces
• Sterilize using dry heat sterilizer at 190 c for 6-12 minutes
• Store

151. Orthodontic brackets
• Speera et al., 2005
Concluded that Chlorhexidine is an appropriate disinfectant to
be used on metal or ceramic brackets.
• evaluated the effect of 0.01 % chlorhexidine solution on metal
and ceramic brackets
• it was found that chlorhexidine does not have a significant
effect on the metal brackets’ adhesion ability

152. Orthodontic bands
• Smith in 1986 AJODO
• Concluded that glass bead sterilization was
sufficient and effective
• bands were placed one at a time into a 226° C
bead sterilizer
• 15 seconds is required to sterilize bacteria and 45
seconds required for spores.
• If five bands were placed in the bead sterilizer
simultaneously, twice the time was required for
sterilization.

153. Orthodontic wires
• Mayhew and Kusy Am. J. Orthod 88
• Neither the heat sterilization nor multiple cycling procedures
had a deleterious effect on the elastic moduli, surface
topography, or tensile properties of Nitinol or Titanal arch
wires
• Pernier et al 2005
• Conducted a study evaluating: influence of autoclaving on the
surface parameters and mechanical properties of six wires
• Concluded that autoclaving had no adverse effects

154. Elastomeric ligatures
• Mayberry et al 1996; Evangelista et al 2007
• Sterilization of elastomeric ligatures inside the autoclave at
121oC does not lead to permanent deformations or to
increased shrinkage whereas in the case of dry-heat, their
manipulation becomes more difficult
• tensile strength of elastomeric ligatures that are not
disinfected is found significantly different than those that are
exposed to phenol and glutaraldehyde

155. • Takla JCO 1998
• Suggested the use of an elastomeric ligature
dispenser
• Elastomeric materials should be handled only
with surgical gloves.
• Partially used canes should not be returned to
the general stock of elastomeric modules.
• A strict single-use dispensing policy is the
ideal situation.

156. Single use devices
• Single-Use (Disposable) Devices
• A single-use (“disposable”) device should be used on only one
patient and then discarded, not cleaned, disinfected, or
sterilized for use on another patient.
• Single-use devices (for example, needles, prophylaxis cups
and brushes, and plastic orthodontic brackets, disposable
trays) are usually not heat-tolerant and cannot be reliably
cleaned.
• Some items such as saliva ejectors, high-volume evacuator
tips, and air/water syringe tips are now commonly available

157. Conclusion
• Keep in mind that every patient is potentially infectious & thus
all measures must be taken during dental practice. The
presence of transmissible diseases like HIV/AIDS and Hepatitis
B & C make it an absolute necessity to protect clinic staff and
patients from cross contamination. Sterilization and
disinfection methods should be implemented meticulously
and their effectiveness carry crucial importance for the
physician’s and patient's health.

158. References
• Textbook Of Microbiology- R.Ananthnarayan 8th Edition
• Disinfection, Sterilization and Preservation – Seymour S.Block
5th Edition
• Alev Aksoy, Gulcın Kılıç, Emad Hussein and Darleen Aboukhalil
(2011). Sterilization and Disinfection in Orthodontics,
Principles in Contemporary Orthodontics