Low-temperature sterilization technologies

1.Low-temperature sterilization technologies
 The most prominent low temperature sterilization methods is ethylene oxide (ETO) and hydrogen peroxide (H2O2) . Low temperature sterilization methods are very useful in dental clinic because many critical reusable medical devices are made of materials and components that cannot withstand the tortuous high temperature and residual moisture prevalent in today’s steam sterilization processes.


(1)Ethylene oxide:
Ethylene oxide is one of the oldest low-temperature sterilization methods. It can be used in  a wide range of equipment, such as porous materials and lumens, without the risk of corrosion. Ethylene oxide destroys microorganisms including their spores by interfering with the metabolic and reproductive processes of the cell. The process in enhance with moisture. The gas chamber is maintained at 20-40% humidity with temperature ranging from 49-60⁰. Timing of the goods depends on the following factors: concentration of ethylene oxide, temperature, humidity and the density and type of materials to be sterilized.

Fig 1:Ethylene Oxide Sterilizer 
 



(2)Hydrogen peroxide gas plasma or vapor
A hydrogen peroxide gas plasma cycle can take as few as 28 minutes, while vapor cycles run about 55 minutes. It can be used in material that cannot tolerate higt temperature and humidity including some plastic, electrical devices and corrosin-susceptible metel alloys.

Fig 2:Hydrogen peroxide Sterilizer 

More information:
1. Healthcare Infection Control Practices Advisory Committee (HICPAC)
2.WHO - Infection Control Guidelines for Transmissible Spongiform Encephalopathies
                                                                    Writte by Chang,yi-chu (Blythe)