EQUIPMENTS AND TECHNIQUES USE IN STERILIZATION

Dr. Lorena Balacanao

CEU- Orthodontic and Pediatric Dentistry Division

Sterilization

is a process that destroy any form of microorganism (beneficial or harmful), viruses, bacteria (which could either be spore forming or non- spore forming) and fungi; thus renders the sterilize material free from germ life or sterile.

Methods that break the chain of infection or interrupt the infectious disease process

1. Sterilization 2. Antiseptics- agents that inhibit

the growth of some microorganism

3. Disinfectant- agents that destroy pathogens other than spores

The procedure for infection control are the following

1. Hand washing and gloving 2. Protection against aerosol and

spatter 3. Instruments asepsis 4. Surface asepsis 5. Management of short and waste

products 6. Aseptic technique

Steps in cleaning and disinfecting

1. Rinse the article with cold water to remove organic materials

Note: hot water coagulates the protein of organic material and tends to make it adhere. E.g. of organic material- pus and blood

2. Wash the article in hot water and soap.

Note: the emulsifying action of soap reduces surface tension and facilitates the removal of dirt. Washing dislodge the emulsified dirt

Step 1 Step 2

3. Use brush and or bristle to clean the grooves and corners. Scrubbing helps to dislodge foreign materials

4. Rinse the article well with warm water-hot water

Step 3 Step 4

5. Dry the article. It is considered clean but not sterile

Clean the brush, gloves and sink. These are considered soiled until they are cleaned appropriately, usually with disinfectant

Step 5 Step 6

Four commonly used methods of sterilization 1. Moist heat 2. Gas 3. Boiling water 4. Radiation

Moist heat ( steam)

2 ways Steam under pressure Free steam

1. Steam under pressure attains temperatures higher than the boiling point.

E.g. Autoclaves supply steam under pressures of 15 to 17 pounds and temperatures of 121 to 123 ° C (250-254 ° F)

The most effective sterilization method/technique

Aberin, et.al. Assessment of terilization Technique used by Dental clinicians

Auto

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Free steam

2. Free steam, 100 ° C (212 °F) is used to sterilize objects that would be destroyed at the higher temperature and pressure of the autoclave. Usually the article is steam for 30 minutes on 3 consecutive days

E.g. bed pan flusher- is not sterilize rather flush by free steam in less than 100 °C. The flusher washes away some of microorganism- hepatitis A virus can survive this free steam application.

Gas

Ethylene oxide gas destroys microorganism by interfering with their metabolic process. It is also effective against spores. Its advantage is good penetration and effectiveness for heat-sensitive items. Its disadvantage is its toxic to humans

Boiling Water

This is the most practical and inexpensive method of sterilization.

Disadvantage spores and some viruses are not killed by this method

The water temperature rises no higher than 100 °C. a minimum of 15 minutes is advised for disinfection of articles in the home

Radiation

2 types Ionizing has a disinfecting effect while Non-ionizing is use to sterilize equipments

E.g. Ultraviolet light uses non-ionizing radiation, this

is use for disinfection because it does not penetrate deeply

Ionizing radiation is use effectively to sterilize foods, drugs and other that is sensitive to heat, its disadvantage is that the equipment is very expensive.

Different methods of Sterilization Dry heat Autoclave Flaming Boiling Tyndallization Chemical or Cold sterilization Radiation Glass beads sterilizer

Tyndallization

A lengthy process, cooling, incubating for a day, and finally boiling again

Chemical or Cold sterilization The agents use can only disinfect but do

not sterilize meaning they do not destroy all bacteria, mould spores or viruses

Formaldehyde, Glutaraldehyde and beta-propiolactone are chemical disinfectant that has a sporicidal effect

These agents are volatile and toxic in skin contact and inhalation

Chemiclave

A mixture of alcohol, ketones, acetones, formaldehyde and water in the temperature of 132° C for 20 minutes

Autoclave

Dry heat sterilizer

Dry heat sterilizer

Glass bead sterilizer

Auto

clave

The end