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DEPERTMENT OF
CONSEVATIVE DENTISTRY &
ENDODONTICS
PRESENTED BY:
SANDIPTA BANERJEE
(FINAL YEAR)
STERILIZATION & INFECTION
CONTROL
Contents
1. Definitions
2. Infection
3. Methods of disinfection
4. Methods of sterilization
5. Most common methods of sterilization
6. Sterilization monitoring
7. Sterilization of Dental instruments
Sterilization
A physical or chemical process that completely destroys or removes all microbial life, including spores.
Disinfection
It is killing or removing of harmful microorganisms
Disinfectant
Products used to kill microorganisms on inanimate objects or surfaces. Disinfectants are not necessarily sporicidal, but may be sporostatic, inhibiting germination or outgrowth
Antiseptic
A product that destroys or inhibits the growth of microorganisms in or on living tissue.
Aseptic
Characterized by the absence of pathogenic microbes.
Infection Control
It is the discipline concerned with preventing nosocomial infection, a practical sub-discipline of epidemiology.
1. DEFINITIONS
2.INFECTION
• Infection is the deposition of organisms in the tissues & their growth resulting in a host reaction.
• The no. of organisms required to cause an infection is termed “The infective dose”. It depends on-
1. Virulence of organism
2. susceptibility of the host
ROUTE OF TRANSMISSION-
1. Direct contact of tissues with infective biological fluids. such as-blood
2. Indirect contact-with contaminated instruments
3. Inhalation of aerosolized infective droplets
4. Direct inoculation into cuts & abrasions of unprotected skin &mucosa
CHAIN OF INFECTION
•Patient to dental team
•Dental team to patient
•Patient to patient
•Dental office to community
• ( include dental team’s
family)
•Community to dental office
to
patient
HOW Diseases Transmitted inDental Office
Common occupational disease
INFECTION CONTROL
• Infection control involves 2 basic factors:
a) Prevention of spread of microorganisms from their hosts(patients & clinician)
b) Killing of removal of microorganisms from objectives & surface
3.METHODS OF DISINFECTION
1. HEAT- boiling in water
flaming of alcohol
pasteurization
2.Physical- ultrasonic cleanser
3.chemical- high level
intermediate level
low level
Level of disinfectant
High
Intermediate
Low
CHEMICAL DISINFECTANT
1.GLUTARALDEHYDE-
- At conc.of 2-3% it provides high level
disinfection for heat sensitive item.
mechanism- It destroys microorganisms by altering
essential protein components.
Ex- CIDEX ,CIDEX PLUS
2.PHENOLS--It is bacteriostatic at about 0.2% conc.
Lethal to most bacteria at 1% & fungicidal
at about 1.3%
mechanism-it acts as a cytoplasmic poison disrupting
the microbial cell walls denaturating
intra cellular proteins
3.ULTRASONIC CLEANSER-
mechanism -Ultrasonic energy produces billions of tiny bubbles in the cleaning solution that collapse&create high turbulence at the surface of the instrument
-this turbulence dislodges the debris
PHYSICAL DISINFECTANT
INFECTION CONTROL STEPS
1. Obtaining health history
2. Immunization recommended for oral health care worker
3. Infection control in dental units
4.Disposal of contaminated waste or house keeping
5.Personal protective equipment
6.Hand washing and care7.Sterilization and infection control
INFECTION CONTROL IN DENTAL
UNIT
•Cleaned by DISPOSIBLE TOWELING
•EPA-ENVIRONMENTAL PROTECTIVE AGENCY
•use an EPA registered hospital disinfectant
•Cleaning Agents LikePHENOLICS, IODOPHORS, CHLORINE
CONTAINING compounds.
CLEANING CLINICAL CONTACT SURFACES
• Risk of transmitting infections greater than for housekeeping surfaces.
• Surface barriers can be used and changed between patient OR
• Clean then disinfect using an
EPA-registered low-(HIV/HBV claim) to
intermediate-level
(tuberculocidal claim) hospital disinfectant.
DISINFECTION & THE DENTAL
LABORATORY
•Discard contaminated items inleak-proof labeled container
•Disposed of according to Tennessee Department of Environment and Conservation Rules
ENVIRONMENTAL SURFACES
• CLINICAL CONTACT SURFACES
–High potential for DIRECT CONTAMINATION from spray or spatter or by contact with gloved hand.
• HOUSEKEEPING SURFACES
–Do not come into contact with patients or devices
– LIMITED RISK of disease transmission
Cleaning Housekeeping
Surfaces
• Routinely clean with SOAP AND WATER or an EPA-REGISTERED DETERGENT/HOSPITAL DISINFECTANT routinely
• Clean MOPS AND CLOTHS and
allow to dry thoroughly before re-using.
• Prepare FRESH CLEANING AND DISINFECTING SOLUTIONS daily and per manufacturer recommendations.
Personal protective equipment
( PPE )
Examination
glovesOver gloves
Sterile surgical
glovesUtility gloves
GLOVES
Dome-shapedFlat types
MOUTH MASKS
PROTECTIVE
EYEWEAR
GOWN
LABORATORY
COAT
Personal protective equipments
• According to the U.S. Centers for Disease Control (CDC) , hand washing is the single most important procedure for preventing the spread of infection. So , you must wash your hands each time before you put on gloves and immediately after you remove gloves .
Hand washing &
hand care :
1. Physical methodsHeatDryMoist ( Autoclave)
RadiationU.V. light Ionizing radiation
Filtration2. Chemical Methods
4. METHODS OF STERILIZATION
5.MOST COMMON METHODS OF
STERILIZATION IN DENTAL OFFICE
• THE STEAM AUTOCLAVE
• CHEMICLAVE
• DRY HEAT OVENS
• OTHERS
-EXPOSURE TO ETHYLENE OXIDE GAS
-IONIZING RADIATION
Sterilization with STEAM UNDER PRESSURE
Time required at 1210 C is 15 mins at 15 lbs of pressure.
Types of autoclaves-1.Simple non jacketed laboratory 2.Steam jacketed with automatic air &
condensate discharge3. High pre vacuum sterilizer
MECHANISM water boils in a closed vessels at
high pressure,temp. at which it boils & that of the steam it forms will riseabove 100 dgree c .moist heat kills microorganisms by the
following mechanisms –protein coagulation-break down of DNA, RNA releasing low mol wt. intracellular constituent
AUTOCLAVE
METHOD OF AUTOCLAVING
The air in the chamber is evacuated and filled with saturated
steam. The chamber is closed tightly the steam keeps on
filling into it and the pressure gradually increases.
The items to be sterilized get completely surrounded by
saturated steam (moist heat) which on contact with the
surface of material to be sterilized condenses to release its
latent heat of condensation which adds to already raised
temperature of steam so that eventually all the
microorganisms in what ever form –are killed.
The usual temperature achieved is 121 °C at a pressure of
15 pps.i. at exposure time of only 15-20 mins. By increasing
the temperature, the time for sterilizing is further reduced.
Advantages• Rapid and effective • Effective for
sterilizing cloth surgicalpacks and towel
packs
Disadvantages• Items sensitive to
heat cannot be sterilized
• It tends to corrode carbon steel burs and instruments
1. Heating Elements2. Temperature Controller3. Pressure Sensor4. Chamber5. Door gasket6. Solenoid valve7. Water level Sensor8. Steam generator9. Vaccum pump
PARTS OF AUTOCLAVE
Autoclave
CHEMICLAVING
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
& 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 sterilized.
DRY HEAT STERILIZATION
Conventional dry heat ovens:
• Achieved at temperature above 1600 C.
• Have heated chambers that allowair to circulate by gravity flow.
• 6-12mins is required for sterilization
• Disadvantages• Without careful calibration, more chances sterilization failures
• The most accurate way to calibrate a sterilization cycle is by using external temperature gauge (pyrometer) attached to a thermocouple wire.
Ethylene oxide-It is a gaseous chemosterilizer alkalates
DNA molecules and thereby inactivates microorganisms.
-Ethylene oxide may cause explosion if used pure so it is mixed with an inert gas e.g. Neon, Freon at a ratio of 10:90 -It requires high humidity and is used at relative humidity 50-60% Temperature : 55-60°C and exposure period 4-6 hours.
- It is employed to sterilize prepackaged laboratory equipment that is otherwise destroyed by heat(e.g., plastic petridishes,Injection plastic syringe)
OTHER STERILIZATION METHOD
6.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
Example
–Geobacillus stearothermophilus
7. DENTAL INSTRUMENTS
CLASSIFICATION BASED ON
RISK OF TRANSMISSION &
NEED OF STERILIZATION
-CRITICAL
-SEMI-CRITICAL
-NON-CRITICAL
CRITICAL INSTRUMENTS
Penetrate MUCOUS MEMBRANES or CONTACT BONE,
BLOODSTREAM, or other normally sterile tissues
HEAT STERILIZE between uses or use sterile single-
use, DISPOSABLE devices
Examples include SURGICAL INSTRUMENTS,
SCALPEL BLADES, PERIODONTAL SCALERS, AND
SURGICAL DENTAL BURS
Contact MUCOUS MEMBRANES but do NOT PENETRATE
SOFT TISSUE
HEAT STERILIZE or HIGH-LEVEL DISINFECT
Examples: DENTAL MOUTH MIRRORS, AMALGAMCONDENSERS,
DENTAL HANDPIECES
SEMI-CRITICAL INSTRUMENTS
Contact intact SKIN
Clean and disinfect using a LOW TO INTERMEDIATE LEVEL
DISINFECTANT
Examples: X-RAY HEADS, FACEBOWS, PULSE OXIMETER,
BLOOD PRESSURE CUFF
NONCRITICAL INSTRUMENTS & DEVICES
STERILIZATION OF DENTAL EQUIPMENTS
EQUIPMENT STERILIZATION METHOD COMMENTS
EQUIPMENT STERILIZATION METHOD COMMENTS
EQUIPMENT STERILIZATION METHOD COMMENTS
EQUIPMENT STERILIZATION METHOD COMMENTS
THANK YOU