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chapter 21
notes 3
Question | Answer |
---|---|
3 sterilization | 1) steam sterilization, 2) chemical vapor sterilization, and ( 3) dry heat sterilization |
Steam autoclave Advantages | short time no corrosion dry quickly |
Unsaturated chemical vapor advantages | short time good penetration of steam Commonly used in dental office |
Dry heat oven type (static air) | no corrosion can use closed containers items are dry after cycle |
Rapid heat transfer (forced air) | very fast no corrosion items are dry after cycle |
autoclave | used to sterilize dental instruments and other items by means of steam under pressure |
Autoclaves four cycles: | (1) heat-up cycle, (2) sterilizing cycle, (3) depressurization cycle, (4) drying cycle. |
Wicking | when bacteria from the air or contaminated surfaces are drawn through the wet packaging material and contaminate the instruments inside |
chemical vapor sterilization | combination of chemicals (alcohol, formaldehyde, ketone, acetone, and water) is used instead of water to create a vapor for sterilizing |
advantage of the chemical vapor sterilizer | it does not rust, dull, or corrode dry metal instruments. |
disadvantage of the chemical vapor sterilizer | adequate ventilation is essential because residual chemical vapors containing formaldehyde and methyl alcohol can be released when the chamber door is opened at the end of the cycle. |
Standard packaging for chemical vapor sterilization includes | film pouches or paper bags, nylon see-through tubing, sterilization wrap, and wrapped cassettes. |
three major factors involved in chemical vapor sterilization | (1) pressure, which should measure 20 psi; (2) temperature, which should measure 270°F (131°C); and (3) time, which should measure 20 to 40 minutes. |
Dry heat sterilizers | operate by heating up air and transferring that heat from the air to the instruments. |
Dry heat sterilizers requires | higher temperatures than are needed for steam or chemical vapor sterilization |
advantage of dry heat | instruments will not rust if they are thoroughly dry before they are placed in the sterilizer |
Two types of dry heat sterilizers | static air and forced air |
Static air | Heat is transferred from the static (nonmoving) air to the instruments in about 1 to 2 hours. |
Disadvantages of static dry heat | (1) the sterilization process is time consuming, and (2) it may not be effective if the operator makes errors in calculating the optimum processing time. |
Forced air sterilizers | rapid heat transfer sterilizers, circulate hot air throughout the chamber at a high velocity |
Exposure time in forced air sterilizers, | ranges from 6 minutes for unpackaged items to 12 minutes for packaged items |
Ethylene oxide gas | method of sterilization |
ethylene oxide sterilization facts | requires 4 to 12 hours ineffective on wet items. Toxicity is a risk if the gas is not handled properly. often are used in large clinics or in hospital settings but rarely in private dental practices |
Sterilizing Instruments with Liquid Chemical Sterilants, p. 297). Sterilization in glutaraldehyde | requires a 10-hour contact time; anything shorter than 10 hours is disinfection, not sterilization |
When a liquid chemical germicide is used for sterilization, certain post sterilization procedures are essential: | 1) Rinse with sterile water after removal to remove toxic or irritating residues, (2) handle with sterile gloves and dry with sterile towels, and (3) deliver to the point of use in an aseptic manner. |