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