This document provides an overview of infection control and sterilization in dentistry. It discusses the definitions of key terms like infection control, sterilization, and disinfection. It describes the modes of disease transmission and outlines strategies to prevent transmission, like personal protective equipment, aseptic techniques, and sterilizing instruments. It also covers topics like operatory asepsis, instrument handling, sterilization monitoring, clinical waste disposal, and managing exposures. The objective is to reduce risks of infection by screening patients, using proper barriers, aseptic techniques, and sterilizing or disinfecting items based on their intended use and potential for infection.

1. PRESENTED BY
DR. M. SHIVA SHANKER
IST YEAR POST GRADUATE STUDENT ,
DEPT OF PERIODONTICS, MAMATA DENTAL COLLEGE.

2. CONTENTS
• INTRODUCTION
• INFECTION
• TRANSMISSION OF INFECTION
• MODE OF TRANSMISSION
• MODE OF INFECTION CONTROL
• INFECTION CONCERN IN
DENTISTRY
•
OBJECTIVES OF INFECTION
CONTROL
•
PERSONAL BARRIER
PROTECTION
•
EMERGENCY & EXPOSURE
INCIDENT PLAN
• OPERATORY ASEPSIS
• DISINFECTION
• INSTRUMENT HANDLING &
CLEANING
• STERILIZATION
• MONITORS OF STERILIZATON
• CLINICAL WASTE DISPOSAL
• STORAGE OF STERILIZED ITEMS
• HANDPIECE ASEPSIS
• CONCLUSION

3. INTRODUCTION
• Microorganisms are ubiquitous.
• Since pathogenic microorganisms cause
contamination, infection and decay, it becomes necessary
to remove or destroy them from materials and areas.
• This is the objective of infection control and sterilization.

4. DEFINITIONS
• INFECTION CONTROL – Also called “exposure control plan” by
OSHA is a required office program that is designed to protect
personnel against risks of exposure to infection.
• STERILIZATION: Use of a physical or chemical procedure to destroy
all microorganisms including substantial numbers of resistant bacterial
spores.
• Sterilization means the destruction of all life forms. (Ronald B Luftig)
• Sterilization is the process of killing or removing all viable organisms.
(MIMS – PLAYFAIR)

5. • STERILE: Free from all living microorganisms; usually described as a
probability (e.g., the probability of a surviving microorganism being 1
in 1 million).
• DISINFECTION: Destruction of pathogenic and other kinds of
microorganisms by physical or chemical means. Disinfection is less
lethal than sterilization, because it destroys the majority of recognized
pathogenic microorganisms, but not necessarily all microbial forms
(e.g., bacterial spores).
• Disinfection is a process of removing or killing most, but not all, viable
organisms.
(MIMSPLAYFAIR)
• Disinfection refers to the destruction of pathogenic organisms.
(Ronald B

6. • DISINFECTANT: A chemical agent used on inanimate objects to
destroy virtually all recognized pathogenic microorganisms, but not
necessarily all microbial forms (e.g., bacterial endospores).
• ASEPSIS: prevention of microbial contamination of living
tissues or
sterile materials by excluding, removing or killing microorganisms.

7. TRANSMISSION OF INFECTION

8. MODES OF TRANSMISSION:
Infectious
agent
Susceptible
host
Reservoirs
Chain of
infection
Portal of
entry
Portal of exit
Means of
transmission
Six links in chain of transmission of infection

9. INFECTION CONCERN IN DENTISTRY
Transmitted by inhalation
Varicella virus
Chicken pox
Paramyxovirus
Measles & Mumps
Rhino/adeno virus
Common cold
Mycobacterium
Tuberculosis
Rubella
German Measles
Candida sp
Candidosis

10. TRANSMITTED BY INOCULATION
Hepatitis B,C,D
Hepatitis
Herpex simplex I
Oral herpes, herpetic whitlow
Herpex simplex II
Genital herpes
HIV
AIDS & ARC
Neisseria gonorrhoeae
Gonorrhoeae
Treponema pallidum
Syphilis
S.aureus/ albus
Wound abscess

11. CROSS
INFECTION
Disease
Hepatitis A
Work restriction
Restrict from patient contact, contact with
patient’s environment, and food-handling.
Duration
Until 7 days after onset of jaundice
Hepatitis B
Personnel with acute or chronic hepatitis B
surface antigenemia who do not perform
exposure-prone procedures
Personnel with acute or chronic hepatitis B e
antigenemia who perform exposure-prone
procedures
No restriction
Hepatitis C
No restrictions on professional activity.
HCV-positive health-care personnel should
follow aseptic technique and standard
precautions.
Restrict from patient contact and contact with Until lesions heal
patient’s environment.
Evaluate need to restrict from care of patients
at high risk.
Hands (herpetic whitlow)
Orofacial
Do not perform exposure-prone invasive
procedures
Until hepatitis B e antigen is negative

12. HIV
Do not perform exposure-prone
invasive procedures.
Rubella
Active
Exclude from duty
Until 5 days after rash appears
Postexposure (susceptible personnel)
Exclude from duty
From seventh day after first exposure
through twenty-first day after last
exposure

13. Staphylococcus aureus infection
Active, draining skin lesions
Carrier state
Streptococcal infection, group A
Restrict from contact with patients
and patient’s environment or food
handling.
No restriction unless personnel are
epidemiologically linked to
transmission of the organism
Restrict from patient care, contact
with patient’s environment, and foodhandling.
Until lesions have resolved
Until 24 hours after adequate
treatment started
Tuberculosis
Active disease
Exclude from duty
PPD converter
No restriction
Until proved noninfectious

14. Varicella (chicken pox)
Active
Exclude from duty
Until all lesions dry and crust
Postexposure (susceptible personnel)
Exclude from duty
From tenth day after first exposure
through twenty-first day (twentyeighth day if varicella-zoster immune
globulin [VZIG] administered) after
last exposure.
Cover lesions, restrict from care of
patients at high risk
Restrict from patient contact
Until all lesions dry and crust
Restrict from patient contact
From tenth day after first exposure
through twenty-first day (twentyeighth day if VZIG administered) after
last exposure; or, if varicella occurs,
when lesions crust and dry
Until all symptoms resolve
Zoster (shingles)
Localized, in healthy person
Generalized or localized in
immunosup- pressed person
Postexposure (susceptible personnel)
Viral respiratory infection, acute
febrile
Consider excluding from the care of
patients at high risk
Until all lesions dry and crust

15. OBJECTIVES OF INFECTION CONTROL
Reduce
Protect
Implement
Simplify

16. STRATEGY TO ACHIEVE INFECTION CONTROL
Screening
PPE
Aseptic techniques
Sterilization &
disinfection
disposal
Laboratory asepsis

17. PREPROCEDURAL MOUTH RINSE

18. CONTINUED…
• Phenolic related essential oils
• Bis-biguanides
• Quaternary ammonium compounds
• Halogens
• Oxygenating agents
• A commercial mouthrinse containing 0.05 percent CPC when used as
a preprocedural mouthrinse was equally effective as CHX in reducing
the levels of spatter bacteria generated during ultrasonic scaling.
Magda Feres et all, JADA 2010

19. HAND HYGIENE

20. • For routine dental examination procedures, hand washing is achieved
by using either a plain or antimicrobial soap and water.
• The purpose of surgical hand antisepsis is to eliminate transient flora
and reduce resident flora to prevent introduction of organisms in the
operative wound, if gloves become punctured or torn.
• At the beginning of a routine treatment period, watches and jewelry
must be removed and hands must be washed with a suitable
cleanser.
• Hands must be lathered for at least 10 seconds, rubbing all surfaces
and rinsed.
• Clean brushes can be used to scrub under and around the nails.
• Must be repeated at least once to remove all soil.

21. HAND CLEANSERS
•
CHLORHEXIDINE BASED – these contain 2- 4% chlorhexidine gluconate
with 4% isopropyl alcohol in a detergent solution with a pH of 5.0 to 6.5.
They have broader activity for special cleansing(e.g: for surgery, glove leaks,
or when clinician experiences injury). But it can be hazardous to eyes.
•
POVIDONE IODONE – contain 7.5-10% povidone iodine, used as a surgical
hand scrub.
•
PARACHLOROMETEXYLENOL(PCMX) – they are bactericidal and
fungicidal at 2% concentration. Non irritating and recommended for routine
use.
•
ALCOHOL HAND RUBS- ethyl alcohol and isopropyl alcohol are widely
used at 70% concentration. They are rapidly germicidal when applied to the
skin.

23. PERSONAL BARRIER PROTECTION
• Personal protective equipment (PPE), or barrier precautions, are a
major component of Standard precautions.
• PPE is essential to protect the skin and the mucous membranes of
personnel from exposure to infectious or potentially infectious
materials.
• The various barriers are gloves, masks, protective eye wear, surgical
head cap & overgarments

24. GLOVES
• Types:
1. Latex gloves

25. VINYL GLOVES

26. NITRILE GLOVES

27. NEOPRENE

28. GENERAL PURPOSE UTILITY GLOVES

29. STEPS IN GLOVING

30. CONTACT DERMATITIS AND LATEX
HYPERSENSITIVITY
• Contact dermatitis is classified as
1. Irritant
2. Allergic.
• Latex hypersensitivity

31. PRECAUTIONS TAKEN FOR LATEX ALLERGIC
PATIENTS
• Be aware that latent allergens in the ambient air can cause respiratory
or anaphylactic symptoms among persons with latex hypersensitivity.
• Patients with latex allergy can be scheduled for the first appointment
of the day to mini- mize their inadvertent exposure to airborne latex
particles.
• Have emergency treatment kits with latex free products available at all
times.

32. MASKS
• Types:
1. Surgical masks (required to have
fluid-resistant properties).
1. Procedure/isolation masks
• Made up from a melt blown placed between non-woven fabric
Layers of a Mask
1. an outer layer
2. a microfiber middle layer - filter large wearer-generated particles
3. a soft, absorbent inner layer - absorbs moisture.
• Available in 2 sizes: regular and petite.

34. N95 PARTICULATE RESPIRATOR
•
National Institute for Occupational Safety and Health (NIOSH) introduced a
rating system which identifies the abilities of respirators to remove the most
difficult particles to filter, referred to as the most penetrating particle size
(MPPS), which is 0.3µm in size.
• The “N” means “Not resistant to oil”.
• N95: captures at least 95% of particles at MPPS.
• N99: captures 99% of particles at MPPS.
• N100: captures 99.97% of particles at MPPS.

35. WHEN SHOULD I WEAR AN N95
RESPIRATOR?
N95 particulate respirator

36. EYE WEAR
• CAUSES OF EYE DAMAGE:
1. Aerosols and spatter may transmit infection
2. Sharp debris projected from mouth while using air turbine
handpiece, ultrasonic scaler may cause eye injury.
3.
Injuries to eyes of patients caused by sharp instruments especially
in supine position

37. OVER GARMENTS
Gown type
Situation and Rationale
Cotton/linen, reusable or disposable, long-sleeved
isolation gowns
Use if contamination of uniform or clothing is likely
or anticipated
Fluid resistant isolation gown or plastic apron over
isolation gown
Use if contamination of uniform or clothing from
significant volumes of blood or body fluids is likely
or anticipated (fluids may wick through non-fluid
resistant reusable or disposable isolation gowns)
Fluid impervious gowns e.g., Gortex®
Use if extended contact or large volume exposure
(e.g., large volume blood loss during resuscitation of
MVA victim or surgical assist)

38. FOOTWEAR
• Most hospitals have their own policies regarding footwear.
• Footwear with open heels and/or holes across the top can increase
the risk of harm to the person wearing them due to more direct
exposure to blood/body fluids or of sharps being dropped for
examples.

39. PRECAUTIONS TO AVOID INJURY
EXPOSURE
• Engineering controls are the primary method to reduce exposures to
blood from sharp instruments and needles
• Work-practice controls establish practices to protect personnel whose
responsibilities include handling, using, or processing sharp devices.
• Sharp end of instruments must be pointed away from the hand
• Avoid handling large number of sharp devices.

40. EMERGENCY & EXPOSURE INCIDENT PLAN
• Management of exposure includes:
1. General wound care and cleaning.
2. Counseling of the exposed worker regarding bloodborne pathogens.
3. Source patient testing for HBV,HCV and HIV (consent required).
4. Documentation of the incident and review.
5. Postexposure assessment and prophylaxis for the health care worker.
6. Baseline and follow up serology of the worker

41. HBV POST EXPOSURE MANAGEMENT
IF
AND
THEN
Source pt is +ve for HBsAG
Exposed worker not vaccinated
Worker should receive vaccine series
should receive single dose of HB
immunoglobulin within 7 days.
Exposed worker has been vaccinated
Should be tested for anti-HBs & given
1 dose of vaccine & 1 dose of HBIG
< 10 IU
Worker should be encouraged to
receive hepatitis B vaccine.
No further action is needed.
Source pt is --ve for HBsAG
Exposed worker not vaccinated
Exposed worker has been vaccinated
Source pt refuses testing or not
identified.
Exposed worker not vaccinated
Exposed worker has been vaccinated
Should receive HB series
HBIG should be considered
Management should be
individualized.

42. HIV POST EXPOSURE MANAGEMENT
IF
THEN
Source pt has AIDS
OR
Source pt is HIV+ve
OR
Source Pt refuses to be tested
 Exposed worker should be
Exposed worker testing –ve initially
counseled about risk of infection. should be retested 6 weeks, 12 weeks
 Should be tested for HIV infection & 6 months after exposure
immediately
 Should be asked to seek medical
advice for any febrile illness
within12 weeks
 Refrain from blood donation &
take appropriate precautions
Source pt is tested & found -ve
Baseline testing of the exposed worker
with follow up testing 12 weeks later
Serological testing must be done &
decisions must be individualized
Source cannot be identified
AND

43. OPERATORY ASEPSIS
• In the dental operatory, environmental surfaces (i.e., a surface or
equipment that does not contact patients directly) can become
contaminated during patient care. Certain surfaces, especially ones
touched frequently (e.g., light handles, unit switches, and drawer
knobs) can serve as reservoirs of microbial contamination, although
they have not been associated directly with transmission of infection
to either personnel or patients.
• Transfer of microorganisms from contaminated environmental
surfaces to patients occurs primarily through personnel hand contact

44. • Almost 40(1939) years ago, Dr. E. H. Spaulding proposed a
classification system for disinfecting and sterilizing medical and
surgical instruments. This system, or variations of it, has been used in
infection control over the years.
Disinfection of surgical instruments in a chemical solution

45. CDC CLASSIFICATION
Category
Definition
Critical
Penetrates soft tissue, contacts bone,
Surgical instruments, periodontal
enters into or contacts the bloodscalers, scalpel blades, surgical dental
stream or other normally sterile tissue. burs
Semicritical
Contacts mucous membranes or
nonintact skin; will not penetrate soft
tissue, contact bone, enter into or
contact the bloodstream or other
normally sterile tissue.
Contacts intact skin.
Noncritical
Dental instrument or item
Dental mouth mirror, amalgam
condenser, reusable dental impression
trays, dental handpieces
Radiograph head/cone, blood pressure
cuff, facebow, pulse oximeter

46. DISINFECTION
• Disinfection is always at least a two-step procedure:
• The initial step involves vigorous scrubbing of the surfaces to be
disinfected and wiping them clean.
• The second step involves wetting the surface with a disinfectant and
leaving it wet for the time prescribed by the manufacturer.

47. • The ideal disinfectant has the following properties:
1. Broad spectrum of activity
2. Acts rapidly
3. Non corrosive
4. Environment friendly
5. Is free of volatile organic compounds
6. Nontoxic & nonstaining

48. • High-level disinfection: Disinfection process that inactivates vegetative
bacteria, mycobacteria, fungi, and viruses but not necessarily high
numbers of bacterial spores.
• Intermediate-level disinfection: Disinfection process that inactivates
vegetative bacteria, the majority of fungi, mycobacteria, and the
majority of viruses (particularly enveloped viruses) but not bacterial
spores.
• Low-level disinfectant: Liquid chemical germicide. OSHA requires lowlevel hospital disinfectants also to have a label claim for potency
against HIV and HBV.
• Gigasept which contains succindialdehyde and
dimethoxytetrahydrofuran are used for disinfection of plastic and
rubber materials eg: dental chair

49. CLEANING AND DISINFECTION STRATEGIES
FOR BLOOD SPILLS
•
Strategies for decontaminating spills of blood and other body fluids differ by
setting and volume of the spill.
•
The person assigned to clean the spill should wear gloves and other PPE as
needed.
•
Visible organic material should be removed with absorbent material (e.g.,
disposable paper towels discarded in a leak-proof, appropriately labeled
container).
•
Nonporous surfaces should be cleaned and then decontaminated with either
an hospital disinfectant effective against HBV and HIV or an disinfectant with
a tuberculocidal claim (i.e., intermediate-level disinfectant).
•
However, if such products are unavailable, a 1:100 dilution of sodium
hypochlorite (e.g., approximately ¼ cup of 5.25% household chlorine bleach

50. PRINCIPLES AND PROCEDURES FOR HANDLING
AND CLEANING INSTRUMENTS AFTER
TREATMENT
•
The safest and most efficient instrument cleaning procedures involve
ultrasonic cleaning of used instruments kept in a perforated basket or
cassette throughout the cleaning procedure.
•
Used instruments are commonly placed in an anti microbial solution as this
softens and loosens debris.
•
Next, move the or basket of instruments into an ultrasonic cleaning device,
rinse them, and then carefully inspect the instruments for debris.
•
Dip instruments likely to rust into a rust inhibitor solution. Drain & dry
instruments with absorbent towel.

51. ULTRASONIC CLEANERS AND SOLUTIONS
•
An ultrasonic cleaner uses sound waves, that are outside the human hearing
range to form oscillating bubbles, a process called cavitation.
•
These bubbles act on debris to remove it from the instruments.
•
Ultrasonic cleaning is the safest and most efficient way to clean sharp
instruments.
•
Operate the tank at one-half to three-fourths full of cleaning solution at all
times- Use only cleaning solutions recommended by ultrasonic device
manufacturers.
•
Operate the ultrasonic cleaner for 3-6 minutes for loose instruments 10-20
mins for cassettes or longer as directed by the manufacturer to give optimal

52. INSTRUMENT WASHER
• Instrument washers use high-velocity hot water and a detergent to
clean instruments.
• These devices require personnel to either place instruments in a
basket or to use instrument cassettes during the cleaning and drying
cycles.
• Types:
1. Counter top model
2. Resembles a kitchen dish washer

53. THERMAL DISINFECTORS
• These devices may look like the instrument washers described above;
however, there is one important difference.
• The high temperature of the water and chemical additives in these
devices cleans and disinfects the instruments.
• Instruments can be more safely handled, and if the dental healthcare
professional were to sustain a puncture injury, it would not require the
follow-up that a contaminated exposure requires

54. NEW SOLAR ENERGY TECHNOLOGY: KILLING
GERMS ON MEDICAL, DENTAL INSTRUMENTS
• “It is completely off-grid, uses sunlight as the energy source, is not
that large, kills disease-causing microbes effectively and relatively
quickly and is easy to operate.
• Halas and colleagues have prototypes of two solar steam machines.
1. The autoclave for sterilizing medical and dental instruments.
2. Autoclave for disinfecting human and animal wastes

55. •
Metallic nanoparticles bits of material so small that hundreds would fit inside
the period go into a container of water.
•
Sunlight focused into the water quickly heats the nanoparticles, which
scientists are terming “nanoheaters.”
•
A layer of steam forms on the nanoheaters and buoys them up to the water’s
surface. They release the steam and sink back down into the water to repeat
the process.
•
“Nanoheaters generate steam at a remarkably high efficiency,” Halas said.
“More than 80 percent of the energy they absorb from sunlight goes into
production of steam.
•
The prototype autoclaves consist of a dish-like mirror that focuses sunlight
into a container of water with the nanoheaters.

56. INSTRUMENT PROCESSING

57. SELECTION OF PACKAGING MATERIALS
FOR STERILIZATION
Steam sterilization
Papers, cellulose, cotton/polyester cloths,
window packs, perforated rigid containers
with bacterial filters, glass containers for
liquids
Dry heat (hot air oven)
Metal canisters and tubes of aluminium foil,
glass tubes, bottles
ETO
Paper & Plastic, perforated rigid containers
with bacterial filters
Low temperature steam
Paper, cloth
Radiation sterilization
Polyethylene, PVC, polypropylene, foil.

58. STERILIZATION
• Stages for instrument sterilization:
1. Presoaking
2. Cleaning
3. Corrosion control and lubrication
4. Packaging
5. Sterilization
6. Handling sterile instruments
7. Storage
8. Distribution

59. AGENTS USED IN STERILIZATION
• Physical agents:
• Chemical agents:
1. Sunlight
1. Alcohols: ethyl, isopropyl,
2. Drying
3. Dryheat: flaming, incineration, hot air
4. Moist heat: pasteurization, boiling,
steam under pressure, steam under
normal pressure.
5. Filtration: candles asbestos pads,
membranes
trichlorobutanol
2. Aldehydes: formaldehyde,
glutaraldehyde
3. Dyes
4. Halogens
5. Phenols
6. Surface-active agents
6. Radiation
7. Metallic salts
7. Ultrasonic and sonic vibrations
8. Gases: ethylene oxide,

60. THE FOUR ACCEPTED METHODS OF
STERILIZATION ARE :
• Steam pressure sterilization (autoclave)
• Chemical vapor pressure sterilization- (chemiclave)
• Dry heat sterilization (dryclave)
• Ethylene oxide sterilization

61. STEAM PRESSURE STERILIZATION
(AUTOCLAVING)

62. •
Advantages of Autoclaves.
1.
Autoclaving is the most rapid and
effective method for sterilizing
cloth surgical packs and towel
packs.
2.
Sterilization is verifiable.
Disadvantages of Autoclaves.
1.
Items sensitive to the elevated
temperature cannot be
autoclaved.
2.
Autoclaving tends to rust carbon
steel instruments and burs.
3.
Instruments must be air dried at
completion of cycle
Is dependable and economical
3.
•

63. TYPES OF AUTOCLAVE
DOWNWARD DISPLACEMENT
• Also known as Gravity displacement unit.
• This is because of the method of air removal in the sterilization chamber.
POSITIVE PRESSURE DISPLACEMENT
• It’s an improvement over downward displacement autoclave.
• Steam is created in a second, separate chamber and held until the proper amount to
displace all of the air in the sterilization chamber is accumulated.
• The steam is then released into the sterilization chamber in a pressurized
blast, forcing the air out through the drain hole and starting the sterilization process

64. • NEGATIVE PRESSURE DISPLACEMENT
• one of the most accurate types of unit available
• Once the sterilization chamber door is closed, a vacuum pump
removes the air.
• Steam is created in a second, separate chamber.
• Once the air has been completely removed from the sterilization
chamber, the steam is then released into the sterilization chamber in a
pressurized blast much like that of a positive pressure displacement
unit.
• The negative pressure displacement unit is able to achieve a high
"Sterility Assurance Level" (SAL), but the system can be quite large
and costly.

65. • TRIPLE VACUUM AUTOCLAVE
• A triple vacuum autoclave is set up/function in a similar fashion to a
negative pressure displacement.
• This is repeated three times, hence the name "triple vacuum"
autoclave. This type of autoclave is suitable for all types of
instruments and is very versatile

66. CLASSIFICATION OF A AUTOCLAVE
Classification
Suitable for
Processing
Eschmann Model
Used by
N Type (Downward
Displacement)
Unwrapped solid
instruments for
immediate use.
SES 2000, Little Sister
3, Little Sister 5
S Type (Vacuum)
Items specified by the
autoclave
manufacturer. N.B.
Eschmann units
suitable for naked and
single wrapped solid
and hollow items.
Little Sister 5 Vacuum
Little Sister Quick Vac
Medical Surgeries
Podiatrist
Tattooist
Body Pierces
B Type (Vacuum)
Unwrapped &
wrapped solid and
hollow instruments.
Porous loads, e.g
drapes & gowns.
Little Sister 3 Vacuum
Dentists
Plastic surgeons
Day surgeries

67. CHEMICAL VAPOR PRESSURE STERILIZATION
(CHEMICLAVING)

68. The 1938 patent of dr. George hollenback and the work of hollenback
and harvey in 1940s culminated in the development of an unsaturated
chemical vapor system , also called harvey chemiclave.
• Advantages
1. Carbon steel and other corrosion-
• Disadvantages
1. Items sensitive to the elevated
sensitive instruments are said to
be sterilized without rust.
2.
Relatively quick turnaround time
for instruments.
3. Load comes out dry.
4. Sterilization is verifiable.
temperature will be damaged.
Vapor odor is offensive, requires
aeration.
2.
Heavy cloth wrappings of surgical
instruments may not be
penetrated to provide sterilization.

69. DRY HEAT STERILIZATION
• Conventional Dry Heat Ovens
• Short-Cycle, High-Temperature
Dry Heat Ovens

70. • Advantages of Dry Heat Sterilization
• Disadvantages of Dry Heat Sterilization
1. Carbon steel instruments and burs do
1. High temperatures may damage
not rust, corrode, if they are well
dried before processing.
2. Industrial forced-draft hot air ovens
usually provide a larger capacity at a
reasonable price.
3. Rapid cycles are possible at high
temperatures.
4. Low initial cost and sterilization is
verifiable.
more heat-sensitive items, such asrubber or plastic goods.
2. Sterilization cycles are prolonged at
the lower temperatures.
3. Must be calibrated and monitored

71. ETHYLENE OXIDE STERILIZATION (ETO)
MOBILE FUMIGATOR

72. • Advantages:
1. Operates effectively at low
• Disadvantages:
1. Potentially mutagenic and
temperatures
2.
3.
4.
carcinogenic.
Gas is extremely penetrative
2.
Can be used for sensitive
equipment like handpieces.
3. Usually only hospital based.
Sterilization is verifiable
Requires aeration chamber
,cycle time lasts hours

73. GAMMA RADIATION
• The Nature of Gamma Radiation A form of pure energy that is generally
characterized by its deep penetration and low dose rates, Gamma Radiation
effectively kills microorganisms throughout.
• Benefits of Gamma Radiation include:
1. precise dosing
2. rapid processing
3. uniform dose distribution
4. system flexibility
5. dosimetric release–the immediate availability of product after processing.
• Penetrating Sterilization: Even with High-Density Products Gamma Radiation is a
penetrating sterilant.
• Substantial Decrease in Organism Survival: Gamma Radiation kills microorganisms
by attacking the DNA molecule.

74. UV RADIATION
•
The wavelength of UV radiation ranges from 328 nm to 210 nm (3280 A to
2100 A). Its maximum bactericidal effect occurs at 240–280 nm
•
Inactivation of microorganisms results from destruction of nucleic acid
through induction of thymine dimers.
•
UV radiation has been employed in the disinfection of drinking water , air,
titanium implants, and contact lenses.
•
The application of UV radiation in the health-care environment (i.e.,
operating rooms, isolation rooms, and biologic safety cabinets) is limited to
destruction of airborne organisms or inactivation of microorganisms on
surfaces

75. FLASH STERILIZATION
•
“Flash” steam sterilization was originally defined by Underwood and Perkins
as sterilization of an unwrapped object at 1320C for 3 minutes at 27-28 lbs.
of pressure in a gravity displacement sterilizer.
•
Currently, the time required for flash sterilization depends on the type of
sterilizer and the type of item (i.e., porous vs non-porous items).
•
•
Uses:
•
Flash sterilization is considered acceptable for processing cleaned patientcare items that cannot be packaged, sterilized, and stored before use.
It also is used when there is insufficient time to sterilize an item by the
preferred package method.

76. OXYGEN PLASMA STERILIZATION
•
Pure oxygen reactive ion etching type of plasmas were applied to inactivate
a biologic indicator, the Bacillus stearothermophilus, to confirm the efficiency
of this process.
•
The sterilization processes took a short time. In situ analysis of the microorganisms’ inactivating time was possible using emission spectrophotometry.
•
The increase in the intensity of the 777.5 nm oxygen line shows the end of
the oxidation of the biologic materials.
•
Files sterilized by autoclave and lasers were completely sterile. Those
sterilized by glass bead were 90% sterile and those with glutaraldehyde
were 80% sterile.
J Indian Soc Pedod Prev Dent. 2010 Jan-Mar;28(1):2-5 Comparison
of the effectiveness of sterilizing endodontic files by 4 different
methods: an in vitro study.

77. EFFECT OF STERILIZATION ON
INSTRUMENTS
Sterilization
Type of instrument
Stainless steel
Carbon steel
Formalin-alcohol vapor at 270°F
Amorphous substance formed near
cutting edge; no dulling.
Cracking of wire edge; no dulling.
Dry heat at 320°F
Chipping of wire edge; no dulling.
Dulling and oxidation of cutting
surfaces
Some oxidation of surfaces; no
dulling.
No visual change.
Dry heat at 340°F
Chipping of wire edge; no dulling.
No visual change
Saturated steam at 250°F
Effects of Sterilization on Periodontal Instruments Roger
B. Parkes,* and Robert A. Kolstadf Accepted for publication 31
August 1981

78. OTHER STERILIZATION METHODS
• Dry-Heat Sterilizers
• Liquid Chemicals
• Performic Acid
• Filtration
• Microwave
• Glass Bead “Sterilizer”
• Vaporized Hydrogen Peroxide
• Formaldehyde Steam
• Gaseous Chlorine Dioxide
• Vaporized Peracetic Acid
• Infrared radiation

79. NEW METHODS OF STERILIZATION
• Various new methods of sterilization are under investigation and
development.
• Peroxide vapor sterilization - an aqueous hydrogen peroxide solution
boils in a heated vaporizer and then flows as a vapor into a
sterilization chamber containing a load of instruments at low pressure
and low temperature
• Ultraviolet light - exposes the contaminants with a lethal dose of
energy in the form of light. The UV light will alter the DNA of the
pathogens. Not effective against RNA viruses like HIV.

80. OZONE
• Ozone sterilization is the newest low-temperature sterilization method
recently introduced in the US and is suitable for many heat sensitive
and moisture sensitive or moisture stable medical devices
• Ozone sterilization is compatible with stainless steel instruments.
• Ozone Parameters • The cycle time is approximately 4.5 hours, at a
temperature of 850F – 940F.

81. STORAGE AND CARE OF STERILE
INSTRUMENTS
• Storage areas should be dust proof, dry, well ventilated and easily accessible for
routine dental use.
• Sterile materials should be stored atleast 8-10 inches from the floor, atleast 18
inches from the ceiling, and atleast 2 inches from the outside walls.
• Items should be positioned so that packaged items are not crushed, bent, crushed,
compressed or punctured.
• Items are not stored in any location where they can become wet.
• Outside shipping containers and corrugated cartons should not be used as
containers in sterile storage areas.
• Ultra violet chambers and formalin chambers are now commonly used for storage of
instruments.

82. MONITORS OF STERILIZATION
• There are 3 methods of monitoring sterilization:
• Mechanical techniques
• Chemical indicators
1. Internal
2. External
• Biological indicators

83. STERILIZATION METHOD
AUTOCLAVE
SPORE TYPE
INCUBATION TEMPERATURE
Bacillus stearothemophilus
56°C
Bacillus subtilis
37°C
B. Pumilus E601
370C
CHEMICAL VAPOR
DRY HEAT
ETHYLENE OXIDE
Gamma radiation
 Sterilization monitoring has four components:
1. a sterilization indicator on the instrument bag, stamped with the date it is
sterilized,
2. daily color-change process-indicator strips,
3. weekly biologic spore test, and
4. documentation notebook.

84. HANDPIECE ASEPSIS
• Oral fluid contamination problems of rotary equipment and especially the high-speed
handpiece involve:
• contamination of hand-piece external surfaces and crevices,
• turbine chamber contamination that enters the mouth,
• water spray retraction and aspiration of oral fluids into the water lines of older dental
units
• growth of environmental aquatic bacteria in water lines
• exposure of personnel to spatter and aerosols generated by intraoral use of rotary
equipment.

85. HANDPIECE SURFACE CONTAMINATION
CONTROL

86. ULTRASONIC SCALARS
•
Soak inserts in a container containing 70% isopropyl alcohol for removal of
organic debris.
•
Rinse cleaned inserts thoroughly in warm water to remove all chemicals. As
a final rinse, replace the insert into the scaler handpiece and operate the
scaler for 10 seconds at the maximum water flow setting to flush out any
retained chemicals
•
•
Dry inserts completely with air syringe
Package in proper wrap, bags, pouches, trays, or cassettes. Add spore
tests and chemical indicators.
• Ethylene Oxide is the preferred method of choice
• Dry heat and chemical vapor methods of sterilization are considered
ineffective methods with risk of damage to materials as per American Dental
association Supplement to J.A.D.A. 8/92.

87. CLINICAL WASTE DISPOSAL
• Red: Anatomical waste
• Yellow: waste which requires disposal by incineration only
• Black: Domestic waste minimum treatment/disposal required is landfill, municipal
incineration.
• Blue: medicinal waste for incineration
• White: amalgam waste for recovery.

88. CONCLUSION
•
Pervasive increases in serious transmissible diseases over the last few
decades have created global concern and impacted the treatment mode of
all health care practitioners.
•
Emphasis has now expanded to assuring and demonstrating to patients that
they are well protected from risks of infectious disease.
•
Infection control has helped to allay concerns of the health care personnel
and instill confidence and in providing a safe environment for both patient
and personnel.

89. •
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•
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•
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REFERENCES:
Pathways of the pulp, 9th edition, armamentarium & sterilization. Cohen
Operative dentistry, infection control, 4th edition, sturdevent.
Grossmans endodontic practice, 11th edition, instrument sterilization.
Textbook of microbiology, sterilization and disinfection, 7th edition, Ananthanarayan
Textbook of clinical periodontology, Newman, Takei, Carranza, 11th edition.
Introduction to sterilization disinfection & infection control, 2nd edition, Joan F Gardner
Sterilization and disinfection of dental instruments by ADA
Disinfection & sterilization of dental instruments TB MED 266, 1995
CDC, guidelines for disinfection & sterilization in health care facilities 2008.
Infection prevention and control, college of respiratory therapists Ontario, june 2011
Effects of sterilization on periodontal instruments, JOP, vol 53, no:7, 1982.
New CDC guidelines for selected infection control procedures, chris miller.
CDC guidelines for infection control in dental health care settings, Dec19, 2003/vol.52.
Sterilization of ultrasonic inserts.