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According to the Centers for Disease Control and Prevention (CDC), sterilization is defined as an instrument reprocessing workflow that "requires a series of steps to assure that contaminated patient-care items are safe for reuse." These steps are required to be performed properly in a specific sequence to ensure that sterilized instruments are used at every dental visit. It is important to remember that regardless of the dental setting, the physical space should be centralized and divided into four zones: cleaning, packaging, sterilizing, and storing. These zones reduce cross-contamination and ensure that proper instrument reprocessing occurs. Each zone has a specific purpose that should be clearly defined to clinical team members to allow them to accurately reprocess every instrument or device. When visiting the centralized sterilization area, be sure to scrutinize the current arrangement. Creating an organized workflow can help to increase efficiency and streamline the entire process.1 The four dedicated zones should be analyzed to include all the necessary equipment, supplies, and signage that adhere to the CDC Guidelines for Dental Settings as well as the Occupational Safety and Health Administration (OSHA) mandates for employee safety.
The sterilization workflow analysis should always begin by establishing if the proper personal protective equipment (PPE) is available for each clinician to don when performing instrument reprocessing. OSHA's Bloodborne pathogens standard states that when there is potential for an occupational exposure to blood or other potentially infectious materials (OPIM), clinicians are required to wear protective eyewear, surgical masks, gowns or lab coats, and utility gloves.2 Inadequate PPE can increase the risk for occupational injury, which decreases the overall safety in the work environment.3
After confirming that adequate PPE is available, the next step is to evaluate the cleaning zone. This area houses equipment and devices necessary in removing contaminants and gross debris from patient care items (Figure 1). The CDC states that cleaning can be done manually or automated, with the latter being the preferred choice. Using automated cleaning equipment such as an ultrasonic cleaner reduces the clinician's risk for injury when handling sharp instruments during the cleaning process. Since automated cleaners are regulated by the Food and Drug Administration (FDA), clinicians are required to follow manufacturer instructions for use (IFU) when operating and performing maintenance on the equipment.4 To ensure optimal use, manufacturers advise using an FDA-approved enzymatic cleaning solution, performing daily degassing, and testing equipment periodically.5 Enzymatic cleaning solutions contain enzymes that act as a detergent to break down debris and help remove stains. It is essential to follow the IFU for these products so that the correct water-to-detergent ratio is achieved for cleaning and damage to patient-care items is avoided. Degassing is a process of removing gases in the ultrasonic cleaning liquid that reduce the efficacy of cavitation. Cavitation is the formation of tiny bubbles that collapse and cause shock waves that help to cleanse debris from patient-care items.6 Degassing should be performed daily prior to the start of each day to ensure that proper cavitation occurs for every cleaning cycle. If using an ultrasonic cleaner, clinicians should also be sure to periodically test the effectiveness of the equipment. Testing is done to confirm that the transducers are working properly for the entire length of the cleaning cycle. Transducers are responsible for creating high-frequency sound waves that agitate the enzymatic cleaning solution causing cavitation. The only way to verify if cavitation occurs is to perform a test using a system recommended by the equipment manufacturer. Lastly, it is important to include a space for the patient-care items to be dried once they have been cleaned. Most dental practices utilize disposable paper towels or reusable cloth towels to dry instruments, but regardless of how drying occurs, all items should be completely dried before being packaged. This allows instruments to emerge completely dry from the sterilizing step and avoids wicking. Storing wet instruments can result in instrument erosion, and wicking is the process of microorganisms entering through wet packaging materials resulting in recontamination.
Once instruments are cleaned, they move to the packaging zone which provides sterility for the patient care devices throughout the sterilization process. The packaging materials must be FDA-approved and, according to the CDC, "should be designed for the type of sterilization process being used and … appropriate for the items being sterilized"7 (Figure 2). To determine the packaging materials, the CDC provides specific recommendations for sterilization methods, package material requirements, and use of acceptable materials (Table 1).7
If using sterilization pouches, the IFU must be followed when sealing the pouches by folding at the perforated line to ensure the proper sterilant penetration for the pouch contents. After packaging, a labeling system should be used on each sterilization pouch or wrapped cassette to track errors or equipment failures. A successful sterilization workflow needs to incorporate this element to monitor proper execution of each step and ensure adherence to compliance standards. When labeling, the CDC states the following should be included: "the sterilizer used, cycle or load number, date of sterilization, and expiration date if applicable."8 CDC also recommends using a waterproof, heat-resistant marker to avoid smearing or bleeding of the ink (Figure 3). Lastly, keep in mind that labeling varies based on the dental setting's governing bodies, and it is recommended to verify requirements prior to implementation.
Next, packaged instruments move to the sterilizing zone where equipment is housed and utilized to kill all microorganisms on the surfaces of the patient-care items. The equipment typically used in a dental setting is a steam autoclave. Its functionality consists of steam directly contacting the instrument surface at a specific temperature for a specific amount of time.9 Like the ultrasonic cleaner, an autoclave must be monitored to ensure proper performance. The CDC states that sterilization equipment should be monitored in three ways: biological, mechanical, and chemical. Biological monitoring uses indicator strips that contain highly resistant, nonpathogenic bacterial spores to test a sterilizer's ability to perform properly. The CDC and OSHA state that biological monitoring should be done on a weekly basis. Mechanical monitoring involves checking the control system, safety valves, and thermostat to establish whether the autoclave is operating correctly. Chemical monitoring consists of chemicals that change color and is used to validate whether the sterilizing agent has internally reached all the pouched or wrapped instruments. Be sure to verify that packaging materials contain an external and internal indicator to maintain compliance. Typically, when using wrapping materials, an internal indicator needs to be manually placed inside of each wrapped cassette. Placing a piece of sterilization tape inside the cassette is not sufficient.10 Next, follow the IFU for loading the autoclave. It is crucial that overloading is avoided, as it can prevent the mechanical parameters from being met and cause the sterilization cycle to be aborted. Once sterilization is complete, allow the dry cycle to finish to prevent storing wet instruments and avoid wicking.11 Lastly, for parameters to be consistently met, manufacturers recommend periodic maintenance to ensure proper functionality of sterilization equipment. Maintenance should be done according the IFU and documented. Maintaining a written account of maintenance provides verification that compliance is being upheld. To ensure proper operation and maintenance is performed according to the IFU, the CDC states that reprocessing instructions should be ideally located in or near the sterilization zone.12
After sterilizing is complete, patient-care items move to the storing zone. Here, these items should be carefully stored in closed cabinets or drawers (Figure 4). To maintain sterility, it is crucial that the chosen cabinets or drawers are not located under sinks or places that could cause sterile packaging to become wet. Lastly, clinical team members should be trained on how to inspect sterilized items when retrieving from the storage area. If packaging is deemed compromised, the patient-care items should be returned to the sterilization area to be reprocessed again (Figure 5).
When examining the sterilization workflow, it is important to address areas that need improvement and identify opportunities to implement new protocols. Consider the physical space, required equipment purchases, and team training that is necessary to carry out mandated guidelines and ensure that every patient receives a safer dental visit.
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About the Author
India R. Chance, RDH, CDIPC
Certified Compliance Consultant
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