This document discusses sterilization, disinfection, and infection control procedures for surgical instruments and implants. It covers key topics such as: - The importance of cleaning instruments before disinfection or sterilization to remove organic materials. - Categorizing instruments as critical, semi-critical, or non-critical based on infection risk to determine the appropriate level of processing needed. - Common sterilization methods like steam sterilization, dry heat, and chemical vapor that are used depending on the material. - Guidelines for disinfecting environmental surfaces and categorizing them based on risk of contamination. - Recommendations for proper hand hygiene and the use of personal protective equipment to

1. Sterilization and disinfection
of instruments and implants
Dr Smarajit Patnaik
Senior Consultant
Orthopaedic Surgeon
Apollo hospitals, Bhubaneswar

2. Contents:
• Definitions
• Classification of instruments
• Decontamination cycle
• Sterilization and its methods
• Principles of sterilization
• Disinfection and its methods
• Agents used for disinfection
• Personal barrier protection
• Conclusion

3. Because maximum effectiveness from
disinfection and sterilization results from first
cleaning and removing organic and inorganic
materials, we will also reviews cleaning
methods.

4. • Disinfection and sterilization are essential for
ensuring that surgical instruments do not
transmit infectious pathogens to patients.
• Because sterilization of all patient-care items
is not necessary, we must identify, whether
cleaning, disinfection, or sterilization is
indicated.

5. Universal precaution Vs Standard
precaution (Q)
• UNIVERSAL PRECAUTION (UP). Universal
Precaution was first introduced on 1987 to
prevent the spread or the transmission of
blood borne pathogens to the health care
providers.
• STANDARD PRECAUTION now constitutes
the primary strategy to prevent the
transmission of infectious agents not only to
the health care personnel but also to patients
and hospital visitors.

6. A Rational Approach to Disinfection
and Sterilization- Spaulding (Q)
• Disinfection can be understood if instruments and items for patient
care were categorized as critical, semicritical, and noncritical based
on degree of risk for infection involved in use of the items.
• Critical items confer a high risk for infection if they are
contaminated with any microorganism. Thus, objects that enter
sterile tissue must be sterile.
• Semicritical items contact mucous membranes or non intact skin.
These medical devices should be free from all microorganisms;
however, small numbers of bacterial spores are permissible.
• Noncritical items are those that come in contact with intact skin
but not mucous membranes. Sterility of items coming in contact
with intact skin is "not critical."

7.  Infection
It is the process of invasion of the tissue by organisms
characterized by their multiplication in the body of
the host to produce disease.
 Infection control:
In medical care, institutional procedures and policies
for monitoring and attempting to control the
transmission of communicable diseases.
• This includes establishing mandatory sanitation,
sterilization, hand hygiene, and isolation procedures.
8
Definition of Terms (Q)

8.  Cleaning
A process which removes visible contamination, but
does not necessarily destroy microorganisms.
 Asepsis
The methods which prevent contamination of wounds
and other sites, by ensuring that only sterile objects
and fluids come into contact with them, and that the
risks of air-borne contamination is minimized.
 Antisepsis
The prevention of infection, usually by inhibiting the
growth of bacteria in wounds or tissues.

9.  Antiseptics
Chemical disinfectants which can be safely applied to
skin or mucous membrane and are used to prevent
infection by inhibiting the growth of bacteria.
 Decontamination
The process of rendering an article or area free of
danger from contaminant, including microbial,
chemical, radioactive and other hazards.

10.  Disinfection
Process which reduces the number of microorganisms
present, but may not inactivate some viruses and
bacterial spores.
 Sterilization
Process that destroys, eliminates or inactivates (kills)
all forms of microbial life including bacterial
endospores.

11. DECONTAMINATION CYCLE
USE
CLEANING
DISINFECTION
INSPECTIONPACKAGING
STERILISATION
STORAGE
proper
sterilisation relies
on a combination
of processes
which together
form an infection
control system

12. Cleaning
• Cleaning is the removal of foreign material (e.g., soil, and
organic material) from objects and is normally
accomplished using water with detergents or enzymatic
products.
• Surgical instruments should be presoaked or rinsed to
prevent drying of blood and to soften or remove blood
from the instruments.
• With manual cleaning, the two essential components are
friction and fluidics.
• For instrument cleaning, a neutral pH detergent solution
commonly is used. Enzymes, usually proteases sometimes
are added to neutral pH solutions to assist in removing
organic material

13. Sterilization
• Steam Sterilization
• Flash Sterilization
• Low-Temperature Sterilization Technologies
• Ethylene Oxide "Gas" Sterilization
• Hydrogen Peroxide Gas Plasma
• Peracetic Acid Sterilization

14. Other Sterilization Methods
• Ionizing Radiation.
• Dry-Heat Sterilizers.
• Liquid Chemicals.
• Microwave
• Ozone.
• Infrared radiation.
• Formaldehyde Steam.
• Gaseous chlorine dioxide

15. Sterilization and its common
methods
3 most commonly used methods of sterilization are:
Steam autoclave
Dry heat oven (dryclave)
Unsaturatedchemicalvapour
sterilizer(Chemiclave)
Other methods are:
Exposure to ethylene oxide gas
Boiling water
Ionizing radiation

16. Moist/ steam heat sterilization
Autoclave (Q)
PRINCIPLE:
• Water boils when its vapor pressure equals that of the
surrounding atmosphere
• Hence when pressure inside a closed vessel increases ,
the temperature at which it boils also increases.
• Saturated steam has penetrative power
• When steam comes into contact with a cooler surface,
it condenses into water and gives up its latent heat to
that surface.

17. 1600ml of steam
at 100°C and 1
atmospheric
pressure
1 ml of water at
100°c
Releases 518
calories of heat
• This large reduction in volume sucks in more steam to
the area & the process continues till the temperature of
that surface is raised to that of the steam
• The condensed water ensures moist conditions for
killing the microbes present

18. • Types of autoclave:
1) Downward (gravitation)
displacement sterilizer
2) Steam sterilizer with pre and
post vacuum processes

19. Phases of Sterilization :
1. Pre-treatment phase/heat up cycle: All air is expelled
by a number of pulses(at least 3) of vacuum and
introduction of steam.
2. Sterilizing phase/Sterilization cycle: Temperature is
increased sufficiently at which sterilization is to take
place.
• Actual sterilizing period is called Holding/plateau time,
starts when the temperature in all parts of the
autoclave chamber and its content has reached the
sterilizing temperature.

20. 3. Post treatment phase / depressurisation cycle and
drying cycle: Steam or revaporized condensed
water is removed by vacuum to ensure that the goods
are dried rapidly.
 Time,temperature and pressure for autoclaving are :
Pressure (Psi) Temperature (°C) Time(mins.)
15 121 15
20 126 10
30 134 3

21. ADVANTAGES
 Most rapid and effective method of sterilization.
 Provides excellent penetration.
DISADVANTAGES
 Corrosion of carbon steel instruments.
 May damage plastic and rubber items.
 Unprotected cutting edges may become dull.

22. Dry heat sterilization (Dryclave)
It effectively sterilizes instruments at high
temperature above 160°C.
Basic action involves dehydration and oxidation of
microorganism.

23. Achieved by 2 methods:
1) Dry heat oven type sterilizer(static air):
160 °C for 60-120 mins
2) Dry heat-rapid heat transfer(forced air):
6 mins for unwrapped instruments at 190 °C.
12 mins for wrapped instruments at 190 °C.

24. Advantages:
 Rapid cycles are possible at high temperature.
 Burs &carbon steel instruments do not rust if they
are well dried before sterilization.
 Large load can be placed.
 Low cost of equipment.

25. Disadvantages:
 Heat sensitive items like rubber or plastics may be
damaged.
 At lower temperature ,sterilization cycles are
prolonged.
 Sterilization is ineffective if there is heavy
instrument load and crowding.

26. Unsaturated chemical vapour
sterilizer (Chemiclave)
• This sterilizer is same as autoclave
unlike it uses special chemical
solution containing formaldehyde
and alcohol.
• The chemical vapour kills
microorganisms by destroying vital
protein systems.
STERLIZATION CYCLE FOR CHEMICLAVE:
Temperature (°C) Pressure(Ibs) Time(minutes)
132 20 20

27. Advantages:
 It does not corrode metals.
 Load comes out dry.
Disadvantages
 High cost of equipment.
 Vapour odor may be offensive and requires increased
ventilation.
 The solution supplied by manufacture has to be used.
 Handpieces cannot be sterilized by this method.

28. ETHYLENE OXIDE STERILIZATION
(Q)
• It is an excellent sterilizer of heat sensitive items as
well as ideal for electric equipment ,flexible fiber
endoscopes and photographic equipment.
• This method uses automatic devices filled with
ethylene oxide gas at temperature below 100˚c to
sterilize complex and delicate materials.
• Ethylene oxide destroys microorganisms by
chemically reacting with nucleic acid.

29. Advantages :
 Most gentle for sensitive equipment like hand pieces.
 Operate effectively at low temperature.
Disadvantages:
 High cost.
 Prolonged time.
 Best for hospitals not practical for dental clinics
 Ethylene oxide gas is potentially mutagenic and
carcinogenic.

30. BOILING WATER
• Boiling water produces temperature of 100̊c at normal
atmospheric pressure which requires 10 mins
exposure to kill bacteria and some viruses.
• When the water starts boiling instruments should be
kept in it and should be fully immersed in it for 20-
30 minutes.
• Cutting instruments should not be sterilized by
boiling as they loose their sharpness.

31. IONIZING RADIATION
• It is effective for heat labile items .
• It is commonly used by industry to sterilize
disposable materials such as needles, syringes, swabs,
catheters, suture material, cannulas.
• High energy gamma rays from cobalt 60 are used to
sterilize such article.

32. If autoclave is not available??? (Q)
• Place all instruments in water immediately after use.
• Remove all debris from the instruments by scrubbing with
brush in soapy water.
• Prepare fire with fuel available.
• Put clean instruments in a pressure cooker and add clean water
in it.
• Place the pressure cooker on the stove and bring it to boil.
• Continue heating the pressure cooker on low heat for a
minimum of 15 minutes.

33. • Ensure that steam continues to be released from pressure
cooker during this time
• Remove pressure cooker from stove after 15 minutes and
leave it to cool.
• Release pressure first before opening the pressure cooker.
• Take instruments out of pressure cooker with instrument
forceps and dry in clean towel.
• Store in a covered box(metal box).

34. DISINFECTION (Q)
Disinfection is a process by which microbes are
removed from an object or surface. This does
not include bacterial endospores. This process
is used to treat articles which do not penetrate
the mucous membrane or skin.

35. Disinfection
Chemical Disinfectants
• Alcohol
• Chlorine and Chlorine Compounds
• Formaldehyde
• Glutaraldehyde
• Hydrogen Peroxide
• Iodophors
• Ortho-phthalaldehyde (OPA)
• Peracetic Acid
• Peracetic Acid and Hydrogen Peroxide
• Phenolics
• Quaternary Ammonium Compounds
Ultraviolet Radiation (UV)
Pasteurization

36. Classification of disinfectants
1. Based on consistency
a. Liquid (E.g.Alcohols, Phenols)
b. Gaseous (Formaldehyde vapor, Ethylene oxide)
2. Based on spectrum of activity
a. High level
b. Intermediate level
c. Low level

37. 3. Based on mechanism of action
a) Action on membrane (E.g.Alcohol, detergent)
b) Denaturation of cellular proteins (E.g.Alcohol, Phenol)
c) Oxidation of essential sulphydryl groups of enzymes (E.g.
H2O2, Halogens)
d) Alkylation of amino-, carboxyl- and hydroxyl group
(E.g.Ethylene Oxide, Formaldehyde)
e) Damage to nucleic acids (Ethylene Oxide, Formaldehyde)

38.  The two methods of achieving disinfection are:
thermal and chemical disinfection.
1. Thermal disinfection (pasteurization)
 By using heat and water at temperatures that destroy
pathogenic, vegetative agents
 Level of disinfection depends on the water temperature
and the duration the instrument is exposed to that
temperature

40. 2. Chemical Disinfection
 The performance of chemical disinfectants is dependent
on a number of factors including: temperature, contact
time, concentration, pH, presence of organic or inorganic
matter and the numbers and resistance of the initial
bioburden on a surface.
 Chemical agents used are:
• Aldehyde (formaldehyde, glutaraldehyde)
• Biguanides (chlorhexidine)
• Halogens (sodium hypochlorite solution)

41. 2% Glutaraldehyde
• Is generally the most appropriate high level
chemical disinfectant.
• Active against most vegetative
bacteria(including M. tuberculosis) and some
viruses including HIV ,fungi and bacterial
spores.
• Can be safely used on metal instruments
(< 24 hrs ), rubber, plastics and porcelain.
• An immersion time of
≥20 min - disinfection
6-10 hours - sterilization
• Must be used under very strict controlled
conditions and in a safe working
environment.

42. Biguanides (Chlorhexidine)
• It is active against bacteria but
not spores, fungi and viruses.
• 0.5% chlorhexidine in 70%alcohol
is used

43. Halogens (sodium hypochlorite solution)
• Active against
bacteria,spores,fungi and
viruses including hepatitis
viruses.
• 1:10 freshly prepared sodium
hypochlorite solution is an
effective surface
disinfectant.

44. Alcohols
• Antibacterial activity against some Gram -ve, some
Gram +ve bacteria (especially against M.
tuberculosis), not effective against spores, viruses
• It acts by denaturing proteins
• 70% alcohol is most effective than high concentration
• Don’t function as disinfectant when simply wiped
(must have minimum of 10 minutes contact)

45. INSTRUMENT PROCESSING

46. Categories of Environmental
Surfaces
1.Clinical contact surfaces
• High potential for direct contamination from spray or
spatter or by contact with DHCP’s gloved hand
• Risk of transmitting infections greater
• Surface barriers can be used and changed between
patients
• Clean then disinfect using an EPA-registered low-
(HIV/HBV claim) to intermediate-level (tuberculocidal
claim) hospital disinfectant

47. 2. Housekeeping surfaces
• Do not come into contact with patients or devices.
• Limited risk of disease transmission.
• Routinely clean with soap and water or an EPA-registered
detergent/hospital disinfectant.
• Clean mops and cloths and allow to dry thoroughly before
re-using.
• Prepare fresh cleaning and disinfecting solutions daily
and per manufacturer recommendations.

48. Personnel Health Elements of an
Infection Control Program
• Education and training
• Immunizations
• Exposure prevention and post-exposure management
• Medical condition management and work-related
illnesses and restrictions
• Health record maintenance

49. Instructions for handwashing
• At the beginning of a routine treatment
period, remove watches, jewelry and rings
then wash hands with suitable cleanser
• Hands should be lathered for at least 10
seconds rubbing all surfaces and rinsed
• Washing should be repeated at least once
to remove all soil

51. • Even good quality surgical gloves develop minor pinholes or
leaks during vigorous use.
• Washing minimizes infection risks secondary to leakage.
• Hand cleansers containing mild antiseptic like 3%
parachlorometaxylenol (PCMX) or chlorhexidine are
preferred to control transient pathogens and to suppress
overgrowth of skin bacteria.

52. Recommendations for Disinfection
and Sterilization based on CDC
guideline:
• Category IA. Strongly recommended for implementation
and strongly supported by well-designed experimental,
clinical, or epidemiologic studies.
• Category IB. Strongly recommended for implementation
and supported by some experimental, clinical, or
epidemiologic studies, and by a strong theoretical rationale.
• Category II. Suggested for implementation and supported
by suggestive clinical or epidemiologic studies or by a
theoretical rationale.
• No recommendation. Unresolved issue. These include
practices for which insufficient evidence or no consensus
exists regarding efficacy.

53. • Meticulously clean patient-care items with water and
detergent, or with water and enzymatic cleaners before
high-level disinfection or sterilization procedures. Category
IB.
• Before use on each patient, sterilize critical surgical devices
and instruments that enter normally sterile tissue or the
vascular system. Category IA.
• Immediately after use, meticulously clean all instruments
and the arthroscope with an enzymatic cleaner that is
compatible. Cleaning is necessary before both automated
and manual disinfection. Category IA.
• Do not flash sterilize implanted surgical devices unless
doing so is unavoidable. Category IB.

54. Methods of Sterilization
• Steam is the preferred method for sterilizing critical medical and
surgical instruments that are not damaged by heat, steam,
pressure, or moisture. Category IA.
• Use low-temperature sterilization technologies (e.g., EtO, hydrogen
peroxide gas plasma) for reprocessing critical patient-care
equipment that is heat or moisture sensitive. Category IA
• Dry-heat sterilization (e.g., 340°F for 60 minutes) can be used to
sterilize items (e.g., powders, oils) that can sustain high
temperatures. Category IB.
• Comply with the sterilizer manufacturer’s instructions regarding the
sterilizer cycle parameters (e.g., time, temperature, concentration).
Category IB.
• Use mechanical, chemical, and biologic monitors to ensure the
effectiveness of the sterilization process. Category IB.

55. CONCLUSION
• Pervasive increases in serious transmissible diseases over
the last few decades have created global concern and
impacted the treatment mode of all dental health care
workers.
• The aim of sterilization and infection control is to control
iatrogenic, nosocomial infections among patients and
potential occupational exposure of care providers to
microbes causing disease during provision of care.
• To prevent occupational exposure and cross-infection health
care provider must be knowledgable about the diseases
commonly encountered and follow high standards of infection
control for the safety of patients and health care workers.