Sterilization IN CONSERVATIVE DENTISTRY

1. Dept. Of Conservative Dentistry &
Endodontics
NORTH BENGAL DENTAL COLLEGE & HOSPITAL
SterilizationOf Operative &
Endodontic Instruments

2. With thewhole world looking at eradication
of existinginfectiousdiseases & preventing
any newinfections,sterilizationof
instrumentsis significantto ensure optimal
patientcare.
Today theuniversal norm is if you can
sterilize an instrument,sterilizeit,otherwise
dispose it off.

3. Definitions:
Sterilization: Process by which
an articles, surface or medium is
freed of all microorganism either
in vegetative or spore form.
Disinfection : Process which
reduces the number of viable
microorganism to an acceptable
level but may not inactivate some
virus and bacterial spores.
Antiseptic : Chemical which can
be safely applied to skin or mucus
membrane surfaces and used for
preventing infection by inhibiting
growth of bacteria.
Cross infection control :Is the
sum total of all the measures
taken to prevent subsequent

4. STERILIZATION
 Most instruments contact
mucosa or penetrate oral
tissues, it is essential that
reused instruments be
thoroughly cleaned and
sterilized by accepted
method that can be
routinely tested and
monitored.
Infection control measures in dentistry are
most vital for mutual health safety of patient
and health care professionals.

5. Instrument
processing
 Contaminated instruments can
transmit infections between patients,
correct reprocessing of instruments
between each patient use is
essential
 Steps Involved
 Presoaking
 Cleaning
 Packaging
 Sterilization
 Drying or cooling

6. Categories of
instruments
Spaulding’s Classification

7. Presoaking:
Most disinfectants do not act in the presence of
debris, so they should be removed. It is easier
to remove the debris before it dries.
 Placing the instrument in a presoak solution
until time is available for full cleaning prevents
drying and begins to dissolve or soften the
debris.
 Presoak solutions used are detergents,
enzymes, phenols, quaternary ammonium
compounds.
Cleaning:
 All items to be sterilized must be properly
cleaned first to reduces bio-burden
 Ultrasonic cleaners
These are safest and most efficient ways to
clean instruments
Ultrasonic cleaning is 9 times more effective
than hand cleaning
An ultrasonic cleaning device provides fast
and thorough cleaning without damage to
instruments
Ultrasonic cleaners

8. Instrument Containment
 Cloth packs, wraps, or plastic bags are
suitable for instrument containment if they are
compatible with the method and temperature of
sterilization.
 Various kinds of instrument trays and cassettes
are manufactured to contain the instruments at
chairside, and they can be placed in an
ultrasonic cleaner, rinsed, and packaged ready
for sterilization.
Selection of packaging
materialsMethod of sterilization Packaging materials
Steam Paper / Plastic pouches /
Wrapped cassettes / Thin
cloth
Chemical vapour Paper wrap / Paper peel
pouches
Dry heat Nylon plastic tubing /
Sterilization paper wrap /
Foil

9. METHODS OF STERILIZATION
Though there are many
methods of sterilization, the
accepted methods of
sterilization in our dental
practices are:
i. Steam pressure sterilization
(AUTOCLAVE)
ii. Chemical vapor pressure
sterilization (CHEMICLAVE)
iii. Dry heat sterilization
(DRYCLAVE)
iv. Ethylene oxide sterilization
(ETOX)

10. AUTOCLAVE
• Sterilization with STEAM UNDER
PRESSURE
• Time required at 1210 C is 15
mins at 15 lbs of pressure.
Advantages
• Rapid and effective
• Effective for sterilizing cloth surgical
packs and towel packs
Disadvantages
• Items sensitive to heat cannot be
sterilized
• It tends to corrode carbon steel burs
and instruments

11. Sterilization Monitoring
Types of Indicators
Physical
 Routine observations of dials
/gauges indicating time
,temperature &
pressure
Chemical
 Color change – strips or tapes
Biological (spore tests)
 Bacillus stereothermophilus (
steam or chemiclave )
 Bacillus subtilus (dry heat )

12. Sterilization Of Burs In Autoclaves
 Burs can be protected by keeping them
submerged in a small amount of 2%
sodium nitrite solution.
 Prepare fresh sodium nitrite solution by
adding 20gms of crystal to 1 liter of water
and place it in a perforated beaker
containing burs.
 The solution should be above the burs by
approximately 1cm
Handpieces sterilization: The internal
surfaces of handpieces become contaminated
with blood & debris,but limited access to internal
surfaces limits its cleaning &
disinfection,thus,surface disinfection is not
adequate. Hand piece must be first cleaned &
then sterilize after each patient.Cleaning can be
done by using water & detergent or wiping the
handpiece using a suitable disinfectant like
alcohol (Fig.11.11).Lubricate the handpiece prior
to sterilization (Fig.11.12) & finally sterilize it by
autoclaving.

13. Steam sterilization
(Autoclave):Temperature &
pressure settings
Items Pressure
(pound)
Temperatur
e(⁰c)
Time (mins)
Blunt
instruments
dressing,glas
s etc.
20 121 30
Rubber
items
20 121 20
Liquids 20 110 20

14. Sterilization
Recommendations:
1. It is preferable to protect the points
of instruments with cotton in order
to prevent bag perforation.
2. Sterilize instruments with hinges in
an open position.
3. Never overfill a sterilizer.
4. In a desktop autoclave,place the
bags & trays vertically & not
horizontally.
5. Allow the drying cycle to finish
completely.
6. All instruments that have been
sterilized should be bagged prior
to storage.
7. Instruments that have been
bagged are considered sterilized

15. CHEMICLAV
Sterilization by CHEMICAL VAPOR
UNDER PRESSURE
• operates at 1310 C and 20 lbs of
pressure.
• They have a cycle time of half an hour.
Advantages
• Carbon steel and other carbon
sensitive burs, instruments
and pliers are sterilized without rust or
corrosion
Disadvantages
• Items sensitive to elevated temperature
will be damaged
• Instruments must be very lightly
packed.
• Towel and heavy clothing cannot be

16. DryHeatSterilization
Conventional dry heat ovens:
•Most common time temperature cycles are
170°C (340°F) for 60 minutes, 160°C (320°F) for
120 minutes, and 150°C (300°F) for 150 minutes.
Recently, more rapid dry heat sterilizers (COX
sterilizers) have become available; these can be
operated at 370°F for 6-, 8- or 12-minute cycles
Advantages
•Carbon steel instruments and burs do not rust,
corrode, or lose their temper or cutting edges if
they are well dried before processing.
Disadvantages
•High temperatures may damage more heat-
sensitive items such as rubber or plastic goods.
•Sterilization cycles are prolonged at lower
temperatures.

17. Ethylene oxide sterilization
 Best method of sterilization of complex
instruments and delicate materials.
 Automatic devices sterilize items in
several hours and operate at elevated
temperature well below 1000 C
 Less expensive device operates at room
temperature to sterilize overnight
Advantages
 Units with large chambers hold more
instruments or packs per cycle
Disadvantages
 Porous or plastic materials absorb the
gas and require aeration for 24 hours or
more before it is safe for them to contact
skin or tissues.

18. Boiling Water
 Boiling water does not kill spores and
cannot sterilize instruments
 Incase of sterilizer breakdown - this
method should be followed
 Well cleaned items must be completely
submerged and allowed to boil at 1000 C
for 10 mins
Cold sterilization: Sterilization by cold
chemical solutions (quaternary ammonium
compounds,ethyl alcohol,isopropyl alcohol,sporicidin
etc) are not recommended for three reasons:
1. The process is not effective against all varities
of microbial life.
2. The length of time necessary of sterilization is
too long,a minimum of 2o minutes.
3. Cold sterilization can be incorporated into the
dental sterilization protocol as a method for
chair-side disinfection of noncritical instrunents
& chair-side accessories & can not replace the
role of steam sterilization.

19. Features Steam
pressure
sterilizatio
n
Chemi-
claving
Dry heat
sterilizatio
n
Ethylene
oxide
sterilizatio
n(ETOX)
Technique 121-134⁰c
at 15-30
pounds for
15 minutes
Chemical
vapour
under
pressure at
131⁰c at 30
pounds
Dry heat
exceeding
160⁰c for
60-90
minutes
Operates
at
temperatur
e below
100⁰c
Clinical
recommen
dations
It is the
most
effective
method for
sterilizing
most
endodontic
instruments
.
Carbon
steel &
corrosion-
sensitive
instruments
can be
sterilized
without
rusting.
Currently
replaced by
more
effective
alternative
techniques
of
sterilization
.
Best way to
sterilize
rotary
handpiece
s.
Techniques of sterilization

20. Endodontic instruments sterilization
 Proper steam autoclaving reliably produced
completely sterile instruments.
 Salt sterilization and glutaraldehyde solutions
may not be adequate sterilization methods
for endodontic hand files and should not be
relied on to provide completely sterile
instruments
 Files sterilized by autoclave and lasers were
completely sterile. Those sterilized by glass
bead were 90% sterile and those with
glutaraldehyde were 80% sterile.
Glass bead sterilizer
Glass bead (hot salt)
sterilizers used to consist of
hot salt or glass beads as a
medium for dry heat
sterilization.The temperature
range employed was
between 425⁰F (218⁰C) & 475⁰F
(246⁰C).However,these are no longer
in clinical use.

21. Individual instruments
can be sterilized in the
following ways -
 Glass slab by swabbing with
tincture of thimerosal, followed by
a double swabbing with alcohol.
 Gutta-percha cones may be kept in
sterile screw capped vials
containing alcohol.
 To sterilize gutta-percha cone
freshly removed from the box-
immerse in 5.2% sodium
hypochlorite for 1 min, then rinse
with hydrogen peroxide and dry
between 2 layers of sterile gauze.

22.  Silver cones are sterilized by
passing them through a flame 3-4
times or by immersion in hot salt
sterilizer for 5 secs.
 Rubber dam is sterilized by
ethylene oxide.
 Carbon steel instruments and
burs are best sterilized by dry
heat or chemiclave.
 Sterilization dental cements,
calcium sulphate is done by
gamma radiation“Whatever is touched is contaminated”

24. Objectives of these
document
The objectives of this document when
implemented, is to control patient-to-patient
infectious disease transmission, and
occupational exposure of dental health care
personnel (DHCP) to infectious, chemical and
other hazards present/encountered during the
practice of dentistry.
This document provides a framework for
developing a concise yet practical curriculum
in dental safety to be implemented in the
didactic and clinical curriculum of
undergraduate dentistry, post-graduate
dentistry, and dental auxiliary programs as an
integral part of educational requirements.
This document provides the framework in
initial and regular periodic continuing dental
education requirements and documentation of
training for all active dental practitioners,
including dental auxiliaries involved in patient
care, as well as supervisory and educational
duties as in clinical faculty.

25. REFERE
NCE
1. Grossman’s ENDODONTIC
PRACTICE-13th edition
2. Sturdevant’s ART & SCIENCE OF
OPERATIVE DENTISTRY-South Asian
Edition
3. Text book of Operative
Dentistry-NISHA GARG & AMIT GARG-
2nd edition
4. www.google.com
Under the guidance of-
1.Prof.Dr.SoumenChakroborty
2.Dr.Anuradha Mukherjee
3.Dr.Debjyoti Karmakar
4.Dr.Dwipayan Bhattacharjee
5.Dr.Partha Sarathi Mandal

26. Thank you