Instrument Processing

By Katherine Schrubbe, RDH, BS, M.Ed, PhD

Proper instrument processing protocols help reduce the risk of cross-contamination

Breaches in instrument reprocessing protocol have put dentistry in the news and emphasize the importance of thorough and consistent infection control protocol. Proper instrument processing is one of the most important practices completed in the dental setting to ensure patient safety. This past summer, a New Jersey dentist caused bacterial endocarditis infections in 15 of his patients, aged 16-77, one of whom died. The claims were outlined in a report from the N.J. Department of Health, entitled, “Outbreak of Enterococcus faecalis endocarditis associated with an oral surgery practice.”¹ Unfortunately, there have been similar stories of breaches in instrument processing that have led to patient harm.

The dental profession relies predominantly on the Occupational Safety and Health Administration (OSHA) standards and U.S. Centers for Disease Control and Prevention (CDC) guidelines to provide a safe environment for employees and patients. Another key organization for instrument processing standards is the Association for the Advancement of Medical Instrumentation (AAMI). Its Standard 79 (ST79) is a comprehensive guide to steam sterilization and sterility assurance in healthcare facilities² that reinforces the CDC Guidelines for Infection Control in Dental Health-Care Settings.³ Although ST79 is not regulatory in nature, it is considered a best practice for steam sterilization, as well as instrument reprocessing and can be helpful in standardizing central sterilization protocols in multiple practice settings.

Six steps
There are typically six steps in the instrument processing cycle. The first – and most important – step is cleaning. Studies have demonstrated that a soiled instrument cannot be sterilized successfully.⁴ Manual cleaning of instruments (scrubbing) is still an acceptable practice, but not highly recommended as it puts the dental team member at risk for occupational injury and cross-contamination. More frequently used are ultrasonic machines, which rely on cavitation to remove soil from an instrument surface. For group practices, where there may be a need to process large quantities of instruments, a washer-disinfector may be a good choice. Although a washer disinfector is similar looking to a home dishwasher, it is a specialized medical device. To aid in the process, cleaning monitors are available on the market, which can be used to demonstrate the cleaning process was successful. Also, it’s important for dental team members to remember to always wear appropriate PPE during instrument processing.

The second step in instrument processing is inspection. This is a simple, but important, step to ensure all soil has been removed prior to sterilization.

After inspection, the third step in the cycle is to ensure that all cleaned instruments are packaged appropriately. Sterilization packages are U.S. Food and Drug Administration (FDA)–approved medical devices, and when cleared by the FDA, they must demonstrate that they maintain sterility for at least 6 months.⁴ AAMI ST79 states that the proper sizing and application of pouches allows for adequate air removal, steam penetration and drying.⁵ The package should provide approximately one inch of space between the items in the pouch and the sealed edges. Cassettes are often used and must also be placed in a sterilization pouch, or wrapped. In each of these options, chemical indicators are used in packaging to provide a visible verification that certain parameters were met inside the sterilizer; the parameters used are time, temperature and steam. CDC guidelines recommend placing an internal chemical indicator (CI) in each package; an external CI should be used when the internal CI is not visible from outside of the package.³ Dual indicator pouches are available through many manufacturers. In the case of cassette use, a separate chemical indicator must be placed inside the cassette, and the packaging (pouch or wrap) must have an external chemical indicator.

The fourth step in the cycle is the sterilization process. The CDC states that steam under pressure is the process of choice whenever possible, as it is considered safe, fast and the most cost effective for healthcare facilities.⁶

Sterile storage is the fifth step in the cycle. Sterilized instruments should be stored in closed or covered cabinets, in low dust areas and well as away from areas where they may become wet. The event-related shelf life method is most commonly used to assess how long packages will remain sterile. This method indicates that the package is sterile indefinitely unless there is an event causing it to be contaminated, such as a tear, brittle plastic, wet packaging or a package that has fallen on the floor.^3,5,7 Any of these compromises call for the package to be reprocessed. Prior to use, packaging should be re-inspected for tears, punctures, open seals or improperly turned CIs. Sterile packages must remain sealed and intact until ready for use.

Quality assurance plays a large role and is the last step in the instrument processing cycle. The quality measures include physical, chemical and biological verification monitoring. All three of these measures are important for patient safety.

Following CDC guidelines, as well as AAMI ST79, takes the guesswork out of preparing instruments that are safe for patients and providers. Regardless of the type or size of the dental setting, a clear understanding of proper instrument processing protocols will reduce the risk of cross-contamination and enhance patient safety.

1. Parsippany Patch. August 26, 2016. http://patch.com/new-jersey/parsippany/n-j-dentist-linked-15-case-bacterial-outbreak-report. Accessed October 7, 2016.
2. Association for the Advancement of Medical Instrumentation. AAMI’s Mission Statement. 2012. Available at: www.aami.org/about/mission.html. Accessed October 7, 2016.
3. Kohn WG, Collins AS, Cleveland JL, et al. Guidelines for infection control in dental health-care settings— 2003. MMWR Recomm Rep. 2003;52:1–61.
4. Miller CH, Palenik CJ. Infection Control and Management of Hazardous Materials for the Dental Team, 4th ed. St. Louis: Mosby Elsevier; 2010:135–167.
5. American National Standards Institute. Comprehensive Guide to Steam Sterilization and Sterility Assurance in Health Care Facilities. Arlington, Va: Association for the Advancement of Medical Instrumentation; 2010.
6. Centers for Disease Control and Prevention. https://www.cdc.gov/hicpac/Disinfection_Sterilization/13_11sterilizingPractices.html. Accessed October 7, 2016.
7. Molinari JA, Harte JA. Cottone’s Practical Infection Control in Dentistry, 3rd ed. Baltimore, Md: Wolters Kluwer/Lippincott Williams & Wilkins; 2010:22–231.

Editor’s Note: Katherine Schrubbe, RDH, BS, M.Ed, PhD, is director of quality assurance at Milwaukee, Wisc.-based Dental Associates.