The document provides information on sterilization and disinfection procedures used in dentistry. It begins with definitions of key terms like sterilization, disinfection, and contamination. It then discusses various sterilization methods like heat, chemicals, filtration, and radiation. Specific techniques covered include autoclaving, dry heat sterilization, ethylene oxide gas sterilization, and pasteurization. The document also addresses testing sterilization efficacy and categorizing instruments based on their ability to be sterilized. Chemical disinfectants like alcohols, aldehydes, and halogens are also summarized.
3. ī Disinfectants
ī Preparation of treatment room
ī Unit water lines
ī Patient preparation
ī Occupational Accidental Exposure
Management
ī Conclusion
ī References
3
4. âĸ Micro organisms are ubiquitous. Since they cause
contamination, infection and decay , it becomes
necessary to remove or destroy them from
materials or from areas.
âĸ Sterilization procedures used in dentistry should
be simple but effective and of relatively short
duration.
4
5. īLOUIS PASTEUR of France was among the
first to use sterilization techniques, he developed
the steam sterilization, hot air oven and the
autoclave. Pasteurization was a method
developed by him to rid of tubercle bacilli from
milk.
īJOSEPH LISTERJOSEPH LISTER,, applied Pasteur's work and
introduced antiseptic technique in surgery
(1867). He is the father of antiseptic surgery.
5
6. STERILIZATION :
Is defined as the process by which an
article, surface or medium is freed of all
living microorganisms either in the
vegetative or in the spore form.
DISINFECTION :
It is the destruction or removal of all
pathogenic organisms to a level which
seems to be no longer harmful to health.
6
7. SEPSIS :
Refers to presence of infection, infectious material
or agent
ASEPSIS :
īļ freedom from infection,
īļ prevention of contact with pathogens
7
8. INFECTION :
Invasion of the body tissues by the pathogenic
bacteria
INFECTION CONTROL :
īļPrevention of spread of micro-organisms from
their hosts
īļKilling or removal of micro-organisms from
objects and surfaces
8
9. CONTAMINATION :
Contamination is the presence of a minor and
unwanted constituent in a material, in a
physical body, in the natural environment, at a
workplace, etc. ..
Decontamination:
It is the process of removal of contaminating
pathogenic microorganisms from the articles by a
process of sterilization or disinfection
9
10. ANTISEPTIC :
Refers to a chemical agent that is used on or in
living tissues to kill or prevent the growth of
microbes.
AEROSOL:
Invisible airborne particles dispersed into the
surrounding environment by dental equipment
(e.g., handpieces, electronic instruments).
10
13. DENTAL CHAIR
âĸControls all foot operated
âĸIf manually operated needs disposable cover
for buttons
âĸSurface should be made up of plastic material
that withstand chemical disinfection without
damage or discoloration .
13
18. SINK
âĸSmooth material (stainless steal)
âĸWide and deep for effective hand washing
without splashing
âĸWater faucets and soap dispensers with
electric knee or foot controlled
18
23. PROCEDURE
īļWear heavy duty gloves and mask
īļDismantle instruments
īļUse detergent and scrub
īļBrush with strokes away from the body
īļRinse thoroughly
īļDry on paper towel
23
26. Procedure
īļInstrument must be completely immersed
īļDismantle instruments with detachable
parts
īļTime accurately by manufacturerâs guide
īļDrain , rinse and air dry
26
27. īĄ Often instruments are packed for sterilization to
be stored and handled without being
contaminated.
īĄ Packing depend on the intended shelf life after
sterilization.
īĄ The available packing options are:
ī§ Textile has shelf life of 1 month
ī§ Paper has shelf life of 1 â 6 months
ī§ Nylon, glass, and metal have shelf life of 1 year if
tightly closed
27
28. Tips on wrapping and packaging
28
īMake sure the instruments donât protrude
from package.
īmore than two layers of wrap.
īPlace biologic or chemical indication along
with packages.
33. âĸ Sunlight possess appreciable bacterial
activity and plays an important role in the
spontaneous sterilization that occurs
under normal conditions
âĸ The action is mainly due to UV rays
âĸ Direct sunlight has germicidal activity.
33
34. âĸ Moisture is essential for growth of
bacteria.
âĸ Drying in air has therefore a deleterious
effect.
âĸ This is unreliable, spores are unaffected.
34
35. The factors influencing sterilization by heat
are
1.Nature of heat.
2.Temperature and time
3.Number of microorganisms
4.Characteristics of organisms
5.Type of material from which organisms
have to be eradicated.
35
36. Red Heat
sterilized by holding them in
Bunsen flame till they become
red hot.
USE :
īļbacteriological loops
īļstraight wires
īļtips of forceps and searing
spatulas
36
37. âĸ This is a method of passing
the article over a Bunsen
flame, but not heating it to
redness,
USE :
īļ Scalpels
īļ mouth of test tubes,
īļ Flasks
īļ glass slides
īļ cover slips
37
38. âĸ This is a method of
destroying contaminated
material by burning them
in incinerator.
USE :
īļ soiled dressings
īļ animal carcasses
īļ pathological material
īļ bedding etc
38
39. This is the most widely used
method of sterilization by dry
heat.
39
TEMPRATURE TIME (minutes)
160 °c 120
170° c 60
150° c 150
140° c 180
40. 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.
40
41. 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.
41
44. ī Ethylene oxide, a gas at temperatures above
108°C, is a highly penetrative, non corrosive
agent with a cidal action against bacteria,
spores and viruses.
ī It destroys microorganisms by alkylation; and
causes denaturation of nucleic acids
44
47. Pasteurization
âĸ Used to kill bacteria in raw milk.
âĸ Holder Method â 63 °c for 30 mins
âĸ Flash Method -72°c for 15 -20 sec
followed by quickly to 13°c or lower
47
49. Hot Water Bath
To inactivate non sporing bacteria for the
preparation of vaccines - Special vaccine
bath at 60o
Cfor one hour is used
Serum or body fluids containing coagulable
proteins can be sterilized by heating for 1 hr
at 56o
C in a water bath for several
successive days.
49
51. Inspissator
Sterilizes by heating at 80-85o
C for half an
hour for 3 successive days
Used to sterilize media such as Lowenstein-
Jensen & Loefllerâs serum
51
53. TEMPERATURE AT
100O
C
Boiling:
Kills vegetative forms of bacterial
pathogens.
īŦHepatitis virus: Can survive up to 30
minutes of boiling.
Endospores: Can survive up to 20 hours or
more of boiling
53
56. A single exposure of 90 min usually
ensures sterilization but for media
containing sugars or gelatin an exposure
of 100c for 20 min on 3 successive days
is used. This is known as
TYNDALLISATION or INTERMITTENT
STERILISATION.
56
57. Invented by Charles Chamberland in 1879
Autoclaves -2 types.
1.Porous load autoclave
2.Small bench top automatic autoclave
Temperature -136°c;
Pressure-32pounds;
Cycle time-5min
flash sterilization.
57
58. âĸ Denaturation and coagulation of microbial
proteins occur during exposure to the high
temperature of the steam.
Temperature: 121c
Pressure : 15psi
Cycle time :15-20 min.
Packing material must allow steam to
penetrate
58
61. 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.
61
62. ī This method uses a combination of dry
saturated steam and formaldehyde to kill
bacteria, spores and most viruses.
ī Formaldehyde acts by alkylation of the
nucleic acids
ī The required combinations of temperature
and pressure are 127 to 132°C at 20 to 40
psi for 30 minutes.
62
64. For sterilization of :
īļEndoscopes
īļCardiac catheters
īļ Respiratory equipment
64
65. 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.
65
66. Following types of filters are used-
1.Candle filters- purification of water for
industrial and drinking purposes.
2.Asbestos filters-
âĸ Disposable, single use discs.
âĸ They have high adsorbing capacity
âĸ Alkalinize filtered liquids.
66
68. 3.Sintered glass filters-
âĸ Are prepared by heat fusing finely
powdered glass particles of graded sizes.
âĸlow absorptive property
âĸbrittle and expensive.
4.Membrane filters-
âĸRoutinely used in water purification and
analysis,
âĸsterilization and sterility testing
âĸpreparation of solutions for parenteral use.
68
69. 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.
69
70. Non Ionizing Radiation
âĸ Electromagnetic rays with longer
wavelengths are used.
âĸ Infra red radiation is considered as a form
of hot air sterilization.
70
71. USE
âĸ Rapid mass sterilization of pre packed
items such as syringes and catheters.
âĸDisinfecting enclosed areas such as
entryways, operation theatres and
laboratories.
71
72. Ionizing radiation-
Also referred as cold sterilization
ī X- rays, gamma rays and cosmic rays are
highly lethal to DNA and other vital
constituents.
ī They have high penetrating power, since
there is no appreciable increase in
temperature.
72
73. USE
âĸCommercial plants use gamma radiation for
sterilizing items like plastics, syringes,
swabs, catheters, animal feeds, oils,
greases, fabrics etc.
73
74. ī Ultrasonic and sonic waves are credited
with bactericidal powers but the results
have been variable.
ī Microorganisms vary in sensitivity to them,
survivors are found even after treatment.
ī Hence it has no practical value in
sterilization and disinfection.
74
78. CONTENT
īChemical agents
īClassification of instrument to be sterilized
īTest for sterilization
īDisinfectants
īInfection in dental operatory
īUniversal precaution
īPatient preparation
īUnit water line
īOccupational accidental exposure management
īWaste
īOsha regulation
78
81. īļ Wide spectrum of activity
īļ Active in the presence of organic matter
īļ Effective in acid as well as alkaline media
īļ Speedy action
īļ High penetrating power
īļ Stable
īļ Compatible with other antiseptics and Disinfectants
īļ Not corrode metals
81
IDEAL CHEMICAL DISINFECTANT
82. īļ Not cause local irritation or sensitization
īļ Not interfere with healing
īļ Not be toxic if absorbed into circulation
īļ Cheap and easily available
īļ Safe and easy to use
82
84. Alcohols :
īEthanol /Isopropyl alcohol are frequently
used
īNo action on spores
īConcentration recommended 60-90% in
water
Uses
īDisinfection of clinical thermometer.
īDisinfection of the skin
84
Spectrum: Effective against fungi, vegetative
bacteria, Mycobacterium species and some
lipid-containing viruses
85. Limitation: Not effective against
spores.
Concentration: Most effective at
70% in water.
Caution: Do not use near flames
due to flammability.
May swell rubber or harden
plastics.
85
87. Formaldehyde gas
ItIt is used for sterilizing instruments and heat
sensitive catheters, for fumigating wards, sick
rooms and labs.
īĄ.
87
īĄ Caution: Formaldehyde can react with free
chlorine to produce toxic gas.
īĄ Irritant vapours are released hence
Neutralise with ammonia following
decontamination
89. 89
Concentration: Glutaraldehyde is
commercially available as 2% w/v
aqueous solution which must be made
alkaline to "activate"
A 2% glutaraldehyde solution, for at
least 10 hours, can be used to
sterilize heat labile items.
A 2% glutaraldehyde solution, for at
least 10 hours, can be used to
sterilize heat labile items.
Spectrum: Active against vegetative
bacteria, spores, fungi and many
viruses.
Spectrum: Active against vegetative
bacteria, spores, fungi and many
viruses.
90. 90
Use:
for instruments such as,
bronchoscopes,
corrugated rubber
anesthetic tubes, face
masks, endotracheal
tubes, metal instruments,
polythene tubing.
Use:
for instruments such as,
bronchoscopes,
corrugated rubber
anesthetic tubes, face
masks, endotracheal
tubes, metal instruments,
polythene tubing.
91. Caution:
īļ Glutaraldehyde is known to cause dermatitis and
asthma.
īļIt should not be used in an area with
little or no ventilation.
īļEye protection, a plastic apron, and gloves must be
worn
īļShould be stored away from heat sources and in
containers with close-fitting lids.
īļThe length of time that glutaraldehyde solutions can
be used varies but they are usually good for up to 14
days.
91
94. Phenols
īThese are obtained by distillation of coal tar
between temperatures of 170c and 270c
īPowerful microbicidal
ī Phenolic derivatives have been widely used as
disinfectants for various purposes in hospitals
īļEg: Lysol, cresol
,
94
95. use :
īTo clean wards
īVarious combinations are used in the control of
pyogenic cocci in surgical & neonatal units in
hospitals.
īAqueous solutions are used in treatment of
wounds
95
96. Metallic salts
ī Salts of silver, copper and mercury are used as
disinfectants.
ī Act by coagulating proteins
ī Marked bacteriostatic, weak bactericidal and
limited fungicidal activity
96
99. ī Improper cleaning of instruments
ī Improper packing
ī Improper temperature in sterilizer
ī Improper loading of sterilizer
ī Improper timing of sterilization cycle
99
100. ī Take the sterilizer out of service
ī Procedures to identify problems
ī Retest and observe the cycle
ī Determine the fate of sterilizer
ī Test the repaired or new sterilizer
100
101. Test for sterilization
Different micro-organism and chemical
indicators
are used for test .
Micro â organism used :
Steam autoclave â
Bacillus stearothermophilus vails ,
ampules or strips.
Dry heat oven â
Bacillus subtilis strips.
Chemical vapour â
Bacillus stearothermophilus strips.
Ethylene oxide â
Bacillus subtilis strips
101
103. ī Broad spectrum of action
ī Fast acting.
ī Not affected by physical factors
ī Non toxic
ī Surface compatability
ī Should not have residual effect on treated
surfaces.
ī Easy to use.
ī Odourless
ī Economical
103
105. ī As a stop gap measure, to use only until the
sterilizable instruments can be obtained.
ī For use in surgical hand washing preparations
ī For disinfection of environmental surfaces
contacted during an appointment.
ī For disinfection of dental appliances prior to
insertion into a patients mouth.
105
107. ī Are those caused by microbes that the patient
carries on or in his or her own body.
ī 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.
107
108. ī Many autogenous infections can be prevented by
preoperative prophylactic therapy.
Eg: endocarditis is prevented by the use of
antibiotics.
108
109. ī Are caused by infectious agents that are
transmitted among dental personnel, patient and
the environment.
ī The transfer of disease may be from dentist to
patient or vice versa.
Eg: hepatitis B is an occupational hazard for dental
personnel , on the other hand there are evidences
of dentists transmitting hepatitis B.
109
110. īļ Patient to practitioner
īļ Practitioner to patient
īļ Patient to patient
īļ Clinic to community
īļ Clinic to practitioners family
īļ Community to patient.
110
111. ī Blood and certain body fluids of all patients are
considered potentially infectious
ī Universal precautions include use of gloves,
gowns, aprons, masks, protective eye wear
ī Precautions to prevent injuries caused by needles,
scalpels and sharps
111
113. ī Wearing apparel is vulnerable to contamination
from spatter, splash, aerosols and patient
contact
ī Gowns should be clean and maintained free
from contamination
ī High necked, long sleeved, knee length
ī Should be changed when visibly soiled
ī Disposable head caps should be worn to prevent
hair from contamination
ī Plastic or disposable apron
113
114. ī Surgical masks or chin length face shields must be
worn to protect face, oral mucosa and nasal
mucosa.
ī Masks should have 95% filtration efficiency of 3 to
5Âĩm in diameter
ī Should be changed for each patient
ī Chin length face shield may be worn
114
116. ī No contact with the wearers lips and nostrils
ī Has a high bacterial filtration efficiency rate
ī Fit snugly
ī No fogging of eye wear
ī Convenient
ī Made of material that does not irritate
ī Does not collapse during wear or when wet
116
117. ī Is necessary to prevent physical injuries and
infections of the eyes.
ī Contamination can be introduced from saliva,
biofilm, carious material, pieces of old restorative
materials during cavity prep, bacteria- laden
calculus during scaling and micro-organism in
aerosols or spatter.
ī Trans conjunctival transmission of hepatitis B
reported â but rare.
117
119. ī Hands serve as a means of transmission of blood,
saliva, dental biofilm
ī Finger nails serve as a reservoir for micro-
organisms
ī Skin breaks serve as a port of entry.
119
120. ī Maintain clean, smoothly trimmed, short finger nails
ī Remove hand and wrist jewelry
ī Never expose open skin lesions or abrasions to
patients oral fluids or tissues
ī After glove removal, wash hands thoroughly
120
122. ī Wearing gloves is the standard practice to protect
both the patient and clinician from cross
contamination
ī Properly fitting gloves protect from exposure
through cuts and abrasions often found on hands.
122
124. ī Always glove and DE glove in front of patient
ī Place gloves over cuff of long sleeved clinic wear
ī Keep gloved hands away from face, hair, clothing,
telephones, pt records, clinicians stool etc
ī Immediately remove torn gloves, wash hands
thoroughly and don new gloves
ī Wash hands promptly after glove removal
124
125. Full mouth disinfection should be done.
It was introduced by Leuven et al in 1990.
īļshould be completed in 2 appointments in 24 hrs
īļScaling and root planing
īļTongue is brushed with chlorhexidiene gel (1%) for 1
minute
īļThe mouth is rinsed with chlorhexidiene
solution(0.2%) for 2 minutes
īļPeriodontal pockets irrigated with chlorhexidiene
solution(1%)
125
127. Procedures for clinical use :
Flush all water lines at least 2 min at the beginning
of each day.
Run water through water syringes for 30 seconds
before and after 30 seconds after each patient
appointment.
127
129. Significant exposure
Premucosal stick or wound with needle or sharp
instrument.
Contamination of any obviously open wound
with blood or saliva.
Exposure of patientâs body fluid to unbroken skin.
129
130. Procedure following Exposure
īImmediately wash the wound.
īThe wound should be encouraged to bleed as
copiously as possible.
īIf the patient has not received hepatitis B
vaccination this should be commenced
immediately.
īIn some cases if hepatitis B positive then hyper
immune gamma globulin is given.
īMany authorities recommend the prophylactic
use of azothymidine for needle stick injuries. 130
131. WHO classified waste as :
1.General non hazardous
2.Sharp
3.Chemical and pharmaceutical
4.Infectious
5.Other hazardous medical waste
131
132. 132
Colour Types of waste
Red Dressings, gloves & other contaminatedDressings, gloves & other contaminated
materialmaterial
Yellow Anatomical parts & lab waste,Anatomical parts & lab waste,
biotechnology, microbiological waste,biotechnology, microbiological waste,
blood , body fluids , bandages, soiled linenblood , body fluids , bandages, soiled linen
Blue Plastics, turbings, catheters, iv sets, syringesPlastics, turbings, catheters, iv sets, syringes
without needleswithout needles
white Glass bottles and vialsGlass bottles and vials
Red can Needles , scalpels, surgical instrumentsNeedles , scalpels, surgical instruments
134. Osha Regulation
1.Employers must provide HB immunization to employees
without charge within 10 days of employment.
2. Employers must require that universal precautions be
observed
3. Employers must implement engineering skills to reduce
production of contaminated spatter, aerosols
4.Employers must implement work practice control
precaution to minimise splashing spatter or contact of
bare hands with contaminated surfaces
5. Employers must provide facilities and instruments for
washing hands, removing gloves and washing other skin
surfaces as soon as possible after contact with blood
134
135. 6. Employers must prescribe safe handling of needles and
other sharps
7.Employers must prescribe disposal of single use needles,
vials and carpules
8.Contaminated reusables must not be stored or processed in
a manner that requires employees to reach hands into
containers to retrieve them
9.Employers must prohibit eating, drinking in the operatory or
clean up area.
10.Place blood and contaminated specimen into suitable
containers
135
136. 11. At no cost to employees, employers must provide
personal protective equipment
12.Contaminated equipment that requires service must first
be decontaminated
13. Contaminated sharps and regulated wastes should be
discarded in hard walled containers
14.Employers must provide laundering of protective
garments
136
137. ī Text book of microbiology â Ananthnarayana &
Paniker â 7th
edition
ī Medical microbiology â greenwood
ī Clinical practices of dental hygenist â Wilkins â 9th
edition
ī Contemporary oral and maxillofacial surgery â
Peterson â 2nd
edition
ī Text book of oral and maxillofacial surgery â
Gustav O. Kruger -6th
edition
137