Factors Affecting Sterilization
Factors that affect sterilization are:
1. Germ factors
If contaminated microorganisms in some tools are reduced excessively due to cleaning, the sterilization needs relatively short contact time.
Natural condition of microorganisms in different species has the sensitivity to different heat or chemicals. The most obvious difference is among vegetative cells and bacterial endospores which the environment can increase or reduce the power of the chemical.
2. Disease transmission factors
In controlling the spread of infection, the action to take is cutting off the link of the disease transmission process, which is known as "circulair chain of the infectious process ", namely:
a) Causative agent is the first link that must be destroyed; usually the cause of this infectious disease is microorganisms such as germs, viruses, fungi and so on. The destruction can be done by sterilization.
Sterilization Methods
1. Chemical and Radiation Sterilization of Medical and Dental Equipment
Chemical Sterilization of Medical and Dental Equipment
In addition to high pressure evaporation or dry heat sterilization, there is chemical sterilization as alternative. A number of high-level disinfectants will kill endospores after prolonged exposure (10-24 hours).
General disinfectant that can be used for chemical sterilization consists of glutaraldehyde and formaldehyde. Sterilization takes place by soaking the instruments for at least 10 hours in 2-4% solution of glutaraldehyde or 8% formaldehyde material soaked for 24 hours.
Radiation Sterilization of Medical and Dental Equipment
Radiation sterilization can be done in several ways:
a) Gas sterilization, the used material is formaldehyde gas, the usage by means of fogging the room with low temperature. In United States and some other countries, ethylene oxide (EtO) is used to do sterilization process of surgical instruments that are sensitive to heat and moisture, such as plastic and instruments, but the sterilization process using ETO is a complicated process (it tooks 2 hours of exposure and 24 hours of aeration).
b) Ultraviolet Sterilization, ultraviolet ray (UV)
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2. Dry Heat Sterilization of Medical and Dental Equipment
Dry heat sterilization is sterilizing equipment using high-heat oven, for example, a sharp metal tool, a tool of glass that is resistant to heat. Dry heat sterilizer can also be used to sterilize endodonticy and dressings endodonticy instruments.
Oven Sterilization by streaming dry air is less efficient as a heat conductor instead of the heat vapor at the same temperature, so it is needed the higher temperature than the use of an autoclave for sterilization. The recommended temperature is maintaining at temperatures of 160 ° C for 2 hours. Exposure for 1 hour with the temperature of 170 ° C is also effective.
Many dentists and doctors places prefer to use dry heat sterilizer in the practices, because it can maintain the sharpness of the tool tip of Surgical Instruments, it does not rust or corrosion as well as effective and safe for the sterilization of metal instruments.
3. High Pressure Hot Steam Sterilization (autoclave) of Medical and Dental Equipment
Efficient sterilization can be obtained by using hot steam at a higher temperature in the form of pressured saturation hot vapor. Hot steam method is a way of sterilizing instrument physically that is oldest and most acceptable.
In the usual application, the autoclave is used for sterilization purposes; the temperature of 1210C is applied for 15-20 minutes. This condition will provide a vapor pressure of 15 pounds. The direct exposure to the saturation vapor at 121 ° C for 10 minutes normally can destroy all forms of microbial life.
