gravity displacement sterilizers, steam is admitted through steam lines, a steam generator, or self- generation of steam within the chamber. Liquid chemical germicides cleared by the FDA as sterilants (e.g., glutaraldehyde, ortho phthalaldehydes, and hydrogen peroxide solutions) may also be used to sterilize heat-sensitive semicritical instruments and devices. However, this method is discouraged for several reasons. First, the sterilization process with liquid chemical sterilants cannot be verified with biological indicators; second, these chemicals may be highly toxic; and finally, instruments sterilized in this fashion are unwrapped yet they must be stored wrapped. Manufacturer’s instructions will indicate proper PPE to be worn (mask, gown, protective eyewear, and heavy-duty utility gloves), as well as adequate room ventilation to ensure dental worker safety when working with these chemicals. Manufacturer’s instructions should also be consulted regarding dilution, immersion time, temperature, and shelf life. Finally, these chemicals may be considered hazardous waste and thus must be disposed of according to local and Immediate-use steam sterilization (flash sterilization) Immediate-use sterilization is a process designed for the steam sterilization of wrapped or unwrapped instruments or patient-care items for immediate use. Unwrapped sterilization should be used only under certain conditions: (1) thorough cleaning and drying of instruments precedes the unwrapped sterilization cycle; (2) mechanical monitors are checked and chemical indicators used for each cycle; (3) care is taken to avoid thermal injury to DHCPs or patients; and (4) items are transported aseptically to the point of use to maintain sterility (CDC, 2008; The Joint Commission, 2020). Unwrapped sterilization of implantable devices is not recommended because all implantable devices should be quarantined after sterilization until the results of biological monitoring are known. Immediate-use sterilization cycles typically operate at higher temperatures for shorter times. However, the manufacturer’s instructions should be consulted for specific requirements. If critical instruments such as surgical instruments are sterilized Sterilization monitoring Effective sterilization monitoring includes a combination of mechanical, chemical, and biological monitoring. Mechanical techniques include assessing cycle time, temperature, and pressure by observing gauges or displays and noting the parameters. Chemical indicators are referred to as internal (enclosed within a cassette or a package) or external (on the outer surface of a cassette or package) and are designated as single-parameter (provides information regarding only one sterilization parameter such as time or temperature) or multi- parameter. Multi-parameter indicators are more chemically sensitive and assess the physical conditions (time, temperature and, sometimes, pressure) during the sterilization process. Internal chemical indicators should be placed within each package or cassette to visualize whether the sterilizing agent has reached the instruments inside. An external chemical indicator should be placed on the outside of the package if the internal indicator cannot be seen. All mechanical and chemical indicators should be checked at the conclusion of the sterilization process. These mechanical and chemical test results do not guarantee that sterilization has taken place, but may be a first indicator of a sterilization problem. If either mechanical or chemical indicators demonstrate deficiencies in sterilization, the load should not be used until it is reprocessed with correct parameters. Biological indicators (BIs) are the most effective technique for monitoring the sterilization process because they directly assess the killing of bacterial spores, rather than merely assessing the physical and chemical conditions necessary for sterilization. Biological monitoring should be done at least weekly on each sterilizer. Manufacturers’ instructions should determine the placement of each BI within the sterilizer. A control BI (from the
state regulations. As a result of the above factors, the CDC recommends a heat-based method of sterilization. Non-heat- tolerant instruments and devices should be replaced with newer heat-tolerant ones. Storage Packages containing sterile instruments and supplies should be inspected prior to their use to confirm that no rips or tears are evident and to note that the packages are dry. Sterile instruments should be stored in closed or covered cabinets if possible, and they should not be stored under sinks or in locations where they could become wet. Wrapped sterilized instruments can be either “date-related” or “event-related.” In date-related practices, all packages should be dated and stored utilizing shelf-life practices. Event-related practices observe that the packages should remain sterile indefinitely, unless an event (such as a tear or moisture) causes them to become contaminated. If packaged instruments are contaminated, they should be reprocessed entirely, including cleaning, drying, packaging, and sterilization. unwrapped, they must be handled aseptically during removal, transported to the point of use, and used immediately. Unwrapped instruments should not be stored for future use because it permits exposure to dust, airborne organisms, and other unnecessary contamination before use on a patient. Several common practices can have a negative effect on the sterilization process. If the sterilizer chamber is improperly loaded or overloaded, the sterilizing agent may not circulate freely between the instrument packs or cassettes, and instrument packs located in the center of the chamber may not be sterilized. In addition, hot or wet instrument packs act as wicks and absorb moisture and bacteria from bare hands. Instrument packs should be allowed to dry and cool in the chamber before removal and the barehanded handling of hot or wet instrument packs avoided. If a package becomes wet, it should be repackaged and resterilized. same lot as the test BI) should not be processed through the sterilizer but should be incubated with the test BI. The control BI should have a positive result, indicating bacterial growth, whereas the test BI should have a negative result. Sterilization records must be maintained in accordance with state and local regulations. If a positive spore test occurs while other indicators reveal that the sterilizer is functioning correctly, the spore test should be repeated immediately. The operator should make sure that the sterilizer is loaded correctly, and then repeat the same cycle that produced the failure. If the repeat test also shows a positive bacterial growth, the sterilizer should be removed from service and records reviewed since the last negative BI test. It is important to review operating procedures with all personnel who operate the sterilizer, noting that operator error is often the cause of failures. If operator error is not a factor (packaging, loading, and operating procedures have been performed correctly), then the sterilizer should be taken out of service until it can be inspected and repaired. The sterilizer should then be tested with three consecutive empty sterilization cycles. If the repeat tests are negative and other monitoring indicates sufficient processing, the sterilizer may be put back into service. Instrument packages should be labeled with the date, sterilizer name (if there is more than one sterilizer in the dental clinic), and cycle load (for easier retrieval in the event of a sterilization failure). These instruments may then be readily retrieved, repackaged, and resterilized. Other key recommendations for sterilization and disinfection of patient-care devices for dentistry include: 1. Cleaning and reprocessing reusable dental equipment according to manufacturer instructions. If the manufacturer
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