STERILIZATION AND DISINFECTION

1. STERILIZATION
&
DISINFECTION

2. purpose
Eliminate all microorganisms that will encounter
body tissues.
Protect patients from possible infection when
natural defenses are not normal

3. Procedures requiring sterile technique
Procedures when underlying tissues are being exposed.
Internal body areas are normally sterile.

4. Sterilization
complete destruction of microorganism
Items must not only be free from microorganism but also
undamaged.
Items must first be clean before sterilized

5. Methods of Sterilization
The three most used forms of heat sterilization
in the dental office are:
• Steam Sterilization
• Chemical Vapor Sterilization
• Dry Heat Sterilization

6. Steam Autoclave Sterilization
Steam sterilization involves heating water to generate steam,
producing a moist heat that rapidly kills microorganisms.
Manufacturers set their sterilizers (autoclaves) to reach
maximum steam temperatures of approximately 250˚ F (121˚ C)
with pressures of 15 or 30 pounds per square inch.
A disadvantage of steam sterilization is that the moisture may
cause corrosion on some high-carbon steel instruments.
Distilled water should be used in autoclaves instead of tap water,
which often contains minerals and impurities. Distilled water
can minimize corrosion and pitting.

8. Types of Steam Sterilizers
All steam sterilizers operate in a similar manner,
but different models and brands have different
features.
There are various sizes of chambers and
mechanisms of air removal, steam generation,
drying, temperature displays, and recording
devices.

9. Chemical Vapor Sterilization
Very similar to autoclaving, except a combination of
chemicals (alcohol, formaldehyde, ketone, acetone, and
water) is used instead of water to create a vapor for
sterilizing.
OSHA requires a material safety data sheet (MSDS) on the
chemical vapor solution because of the toxicity of the
chemicals it contains.
The major advantage of the chemical vapor sterilizer is that it
does not rust, dull, or corrode dry metal instruments.
A wide range of items can be sterilized routinely without
damage. Other advantages are the short cycle time and
having a dry instrument at the end of the cycle.
OSHA Occupational Safety and Health Administration

10. Chemical Vapor Sterilization

11. Monitoring Chemical Vapors
The primary disadvantage is that adequate ventilation is
essential because residual chemical vapors containing
formaldehyde and methyl alcohol can be released when the
chamber door is opened at the end of the cycle.
These vapors can temporarily leave an unpleasant odor in the
area and may be irritating to the eyes.
Newer models are equipped with a special filtration device that
further reduces the amount of chemical vapor remaining in the
chamber at the end of the cycle.
Formaldehyde monitor badges that are worn by the employee
(much like radiation monitoring devices) are available.

12. Pressure, Temperature, and Time
The three major factors in chemical vapor
sterilization are:
Pressure (20 psi)
Temperature 131˚ C (270˚ F)
Time (20 to 40 minutes)

13. HOT AIR (DRY HEAT)

14. MICROWAVE
Uses low – pressure steam along
with the nonionizing radiation

15. What is Gas Plasma ?
Plasma is a fourth state of matter which is distinguishable from
liquid, solid, or gas. In nature, plasma is widespread in outer space.
Gas plasma generated in an enclosed chamber under deep vacuum
using Radio frequency or Microwave to excite gas molecules are
produced charged particles
HYDROGEN PEROXIDE PLASMA VAPOR
STERILIZATION & DISINFECTION

16. OZONE GAS
expensive and easy to operate
CORROSIVE!!!
NOT USED FOR ITEMS MADE OF
STEEL AND ALUMINUM

17. Liquid Chemical Sterilant Peracetic Acid
• Liquid sterilant.
• Suitable for sterilizing heat – sensitive items
• Rinse in sterile water before using
• Can be used immediately

18. Peracetic Acid
Peracetic, or peroxyacetic, acid is characterized by a
very rapid action against all microorganisms.
A special advantage of peracetic acid is it has no
harmful decomposition products (i.e., acetic acid,
water, oxygen, hydrogen peroxide) and leaves no
residue. It remains effective in the presence of organic
matter and is sporicidal even at low temperatures
STERILIZATION & DISINFECTION

19. IONIZING RADIATION
EXPOSURE TO IRRADIATION
IRRADIATION STERILIZATION IS
SUITABLE FOR HEAT AND MOISTURE
SENSITIVE ITEMS

20. Sterilization Monitoring
Types of Indicators
• Mechanical
•Measure time, temperature, pressure
• Chemical
•Change in color when physical parameter is
reached
• Biological (spore tests)
•Use biological spores to assess the sterilization
process directly

21. PACKAGE WITH STERILE INDICATORS

22. GENERAL PRINCIPLES
1. Microorganisms move through space in air
currents
2. Microorganisms are transferred from one surface
to another when a non-sterile object touches other
objects
3. Microorganism move from one object to another as
a result of gravity when a non-sterile item is held
above another item

23. 4. Microorganisms travel rapidly along any
moisture .
5. Microorganisms move slowly along a dry surface.
6. Microorganisms are releases through the air on
droplets whenever a person breathes or speaks
GENERAL PRINCIPLES

24. ALWAYS REMEMBER!!!
WHEN IN DOUBT OF
STERILITY DISCARD!!!

25. Thank you
STERILIZATION & DISINFECTION