Microbiology and Infection Control. Chapters 21, 23. Test 3 Flashcards
What are the three instrument classifications used to determine the method of sterilization?
- critical (Item used to penetrate soft tissue or bone. Example, forceps, scalpels, bone chisels, scalers, and burs)
- semicritical (touch mucous membranes or non-intact skin and have a lower risk for transmission. Example, plastic-handled dental material applications, dental dam forceps, x-ray image holders, and amalgam carriers)
- noncritical (pose the least risk for transmission of infection because they contact only intact skin, which is an effective barrier to microorganisms. Example, x-ray unit tube head, the lead apron, and the curing light that comes into contact only with intact skin).
What is the basic rule of the workflow pattern in an instrument processing area?
Processing of instruments should proceed in a single loop, from dirty, to clean, to sterile, to storage, without ever “doubling back”.
The pattern of workflow:
1. receiving and sorting.
2. preparation and packaging.
3. sterilization.
4. storage
Name the three methods of precleaning instruments.
Instruments are precleaned by using a holding solution, and with the use of an ultrasonic cleaner or instrument washing machine.
How does an ultrasonic cleaner work?
Ultrasonic cleaners are used to loosen and remove debris from instruments.
The ultrasonic cleaner works by producing sound waves beyond the range of human hearing. These sound waves, which can travel through metal and glass containers, cause cavitation (formation of bubbles in liquid). The bubbles, which are too small to be seen, burst by implosion (bursting inward – the opposite of an explosion). The mechanical cleaning action of the bursting bubbles combines with the chemical action of the ultrasonic solution removes the debris from instruments.
The time may vary from 5 to 15 minutes.
How can instrument rusting be prevented?
Instruments and burs made of carbon steel will rust during steam sterilization. Rust inhibitors such as sodium nitrate or commercial products are available as a spray or dip solution and help to reduce rust and corrosion.
An alternative to sing rust inhibitors is to dry the instrument thoroughly with dry heat or unsaturated chemical vapor sterilization.
Hinged instruments may have to be lubricated to maintain proper opening. Take care to remove all excess lubricant before performing heat sterilization.
What are the most common forms of heat sterilization?
steam sterilization (steam autoclave), chemical vapor sterilization (unsaturated), and dry heat sterilization (two types: static air and forced air, also called rapid heat transfer sterilizers).
Also. There are Ethylene oxide sterilization and Liquid chemical sterilants.
What is a primary disadvantage of flash sterilization?
Unwrapped instruments are no longer sterile once they are removed from the sterilizer and before they are used on the next patient.
Flash sterilization should be used only for instruments that are to be used promptly upon removal from the sterilizer.
What is a primary advantage of chemical vapor sterilization?
The major advantage of the chemical vapor sterilizer is that it does not rust, dull, or corrode dry metal instruments.
3 major factors involved in chemical vapor sterilization:
pressure 20 psi
temperature 270 degree F (131 C)
time 20-40 mins
What are the two types of dry heat sterilization?
Static air and forced air, also called rapid heat transfer sterilizers. 320 to 375 degree F. (160 C to 190C).
Static air sterilizers are similar to oven. The heating coils are on the bottom of the chamber, and the hot air rises inside through natural convection. About 1 to 2 hours. Aluminum foil, metal, and glass containers may be used. Paper and cloth should be avoided. 1 - 2 hours
Forced air sterilizers, circulate air throughout the chamber at a high velocity. After the sterilizing temperature has been reached, ranges from 6 for unpackaged items to 12 minutes for packaged items.
What is the primary disadvantage of liquid chemical sterilization?
Requires a 10-hour contact time; anything shorter than 10 hours is disinfection, not sterilization.
What are the three forms of sterilization monitoring?
physical, chemical, and biologic
What is a process indicator, and where is it placed?
Process indicators (external) are placed outside of instrument packages before sterilization.
Process indicators simply identify instruments packs that have been exposed to a certain temperature; they do not measure the duration or the pressure.
Process indicators are also known as single-parameter indicators. Process indicators are useful in distinguishing between packages that were processed and those that were not processed.
What is a process integrator, and where is it placed?
Process integrators (internal) are placed inside instruments packages. They respond to a combination of pressure, temperature, and time. Also known as multiparameter indicators. All sterilization factors are integrated.
The advantage of placing integrators inside each package is that penetration of the packaging by the sterilizing agent is ensured.
What is the best way to determine whether sterilization has occurred?
Biological monitoring, or spore testing, is the only way to determine whether sterilization has occurred and to confirm that all bacteria and endospores have been killed.
How should high-speed handpieces be processed before sterilization?
Flushing the handpiece is the best way to remove debris from the head of the handpiece.
To flush a dental handpiece, attach a pressurized handpiece cleaner to the intake tube of the handpiece (where the air passes through), and flush the head of the handpiece to remove debris. Afterward, blow out the handpiece using compressed air to remove debris before sterilization. Most handpieces should not be run without a bur in place.
What types of heat sterilization are appropriate for high-speed handpieces?
Only steam and chemical vapor heat sterilization are recommended because handpiece sterilization temperatures should not exceed 275 F (135C).
Never run a handpiece “hot” out of the sterilizer, and avoid rapid cool-downs, such as running the handpiece under cold water. Handpieces use very small metal components; extreme cold changes stress the metal.
What does event related packaging mean?
It means that unless some event occurs (for example, a torn or wet package) to contaminate the contents it is assumed that the contents will remain sterile.
