Sterilization is the process of eliminating all microorganisms through physical, chemical, or physiochemical means and is crucial for infection control in dental practices given patients' mouths harbor many microbes. Critical and semi-critical dental instruments that contact blood or tissues must be sterilized after each use through methods like steam under pressure via autoclaving, dry heat, or chemical vapor. Proper sterilization and disinfection procedures according to instrument classification help reduce transmission of infections between patients and staff.

1. D R . S UL TA N Z A H I R
STERILIZATION IN
DENTISTRY

2. STERILIZATION & DISINFECTION
• Sterilization is defined as the process where all the living
microorganisms, including bacterial spores are killed.
• Sterilization can be achieved by physical, chemical and
physiochemical means. Chemicals used as sterilizing
agents are called chemisterilants.
• Disinfection is the process of elimination of most
pathogenic microorganisms (excluding bacterial spores)
on inanimate objects. Disinfection can be achieved by
physical or chemical methods. Chemicals used in
disinfection are called disinfectants. Different
disinfectants have different target ranges, not all
disinfectants can kill all microorganisms.

3. IMPORTANCE OF STERILIZATION
• Sterilization procedures are very important to any
good dental practice. These are a part of basic
care and handling of patients. Patients mouth are
teeming with microbes, and any dental office that
sees a large number of patients a day has an
inherent potential for spreading infectious germs
between patients and dental staff, through
contaminated instruments and surfaces. These can
be greatly minimized by following proper infection
control procedures.

4. • Good dental infection control starts with the
dentist’s room itself. A well-ventilated room with air-
circulating devices prevents building up of aerosols
produced from the dental drills. The sterile dentist
and assistant are immunized against hepatitis, wear
clean personal protective equipment—a scrub
apron, eyewear, disposable gloves and facemasks.
The patient is draped, and may be given a
protective ―face shield‖ to prevent skin
contamination from the dental drill’s water spray.
An anti-microbial mouth rinse just before a dental
procedure is important to reduce contamination.

5. • The dental chair’s knobs and handles need to be
chemically disinfected between patients.
• Surgical procedures require more stringent
measures to eradicate all chances of infection and
need special preparation of the dentist’s room. The
dentist, assistant and patient all need sterilized
gowns, and all instruments, drills, suction apparatus
has to be completely sterilized.

6. STERILIZATION AND DISINFECTION
OF DENTAL INSTRUMENTS
• According to the Centers for Disease Control,
dental instruments are classified into three
categories depending on the risk of transmitting
infection.
• Critical
• Semi critical
• Non critical

7. • Critical instruments are those used to penetrate soft
tissue or bone, or enter into or contact the
bloodstream or other normally sterile tissue. They
should be sterilized after each use. Sterilization is
achieved by steam under pressure (autoclaving),
dry heat, or heat/chemical vapor. Critical
instruments include forceps, scalpels, bone chisels,
scalers and surgical burs.

8. • Semi-critical instruments are those that do not
penetrate soft tissues or bone but contact mucous
membranes or non-intact skin, such as mirrors,
reusable impression trays and amalgam
condensers. These devices also should be sterilized
after each use. In some cases, however, sterilization
is not feasible and, therefore, high-level disinfection
is appropriate.

9. • Non-critical instruments are those that come into
contact only with intact skin such as external
components of x-ray heads, blood pressure cuffs
and pulse oximeters. Such devices have a relatively
low risk of transmitting infection; and, therefore, may
be reprocessed between patients by intermediate-
level or low-level disinfection.
• An intermediate-level disinfectant (e.g., phenolics,
iodophors, and chlorine-containing compounds).
• A low-level disinfectant (e.g., quaternary
ammonium compounds).

10. METHODS OF STERILIZATION
Microbial
Control
Methods
Physical Agents
Chemical
Agents
Mechanical
Removal
Methods

12. Chemical
Agent
Gas
Sterilization Disinfection
Liquids
Animate
Chemotherapy Antiseptics
Inanimate
Sterilization Disinfection

13. Mechanical
Removal
Methods
Filtration
Air
Disinfection
Liquids
Sterilization

14. PHYSICAL METHODS OF STERILIZATION
• Dry Heat Sterilization
• Kills by oxidation effects
•The oven utilizes dry heat to
sterilize articles
• Operated between 50oC to
250/300oC.
•A holding period of 160oC for 1 hr
is desirable.
• There is a thermostat controlling
the temperature.
•Double walled insulation keeps the
heat in and conserves energy,

15. DRY HEAT STERILIZATION USE
• To sterilize Forceps, Scissors, Scalpels, Swabs.
• Pharmaceuticals products like Liquid paraffin, dusting powder, fats
and grease.

16. MOIST HEAT STERILIZATION
• Kills microorganisms by coagulating their proteins.
MOIST HEAT STERILISATION IS CARRIED OUT WITH
FOLLOWING METHODS:
• Temp below 100oC: ―Pasteurization‖, Inspissator.
• Temperature at 100oC: Boiling.
• Steam at atmospheric pressure: Koch/Arnold’s steamer.
• Steam under pressure: Autoclave.

17. STEAM UNDER PRESSURE -
AUTOCLAVE

18. AUTOCLAVE
• Autoclave consists of a vertical or a horizontal cylinder.
• One end has an opening which is meant for keeping
materials to be sterilized.
• The lid is provided with a Pressure gauge, to measure the
pressure
• A safety valve is present to permit the escape of steam
from the chamber
• Articles to be sterilized are placed in the basket provided
• Sterilization is carried out under pressure at 121º for 15
minutes.

19. CHEMICAL AGENTS
 Alcohol –Ethanol, isopropyl alcohol
 Aldehyde – Formaldehyde, Glutaraldehyde
 Ethylene oxide
 Dyes
 Halogens- iodine, Iodophores, Sodium hypochlorite
 Phenolics- Carbolic acid 2.5%
 Surface active agents
 Metallic salts
 Diguanides
 Amides

20. ETHYLENE OXIDE
• Highly inflammable, mixed with inert gases – CO2, N
• Especially for sutures, syringes & all dental
equipment's

21. RADIATION
Two types of radiations are used
NON –IONISING
IONISING
• Non ionizing –
• Infra Red radiation ( rapid mass sterilization of syringes,
etc.)
• Ultra Violet radiation (enclosed areas)
• Ionizing – Gamma, X ray, cathode ray
(plastics, syringes, oil, metal foils)

22. •Infection control measures not
only reduce the chances of
getting a dental infection, they
also reduce the risk of catching
serious diseases like HIV and
hepatitis.