Sterilization of instruments: successes and pitfalls Part 2 -- sterilization monitoring
By Leslie Canham, CDA, RDA
How do you know that your dental instruments are sterile? According to the Centers for Disease Control and Prevention (CDC), sterilization procedures should be monitored through a combination of mechanical, chemical, and biological techniques designed to evaluate the sterilizing conditions and the procedure's effectiveness. Last month’s article, “Sterilization of instruments: successes and pitfalls Part 1: sterilizers and sterilization packaging,” focused on types of sterilizers and types of packaging materials. This article will cover the various types of sterilization monitoring and what to do in the event of sterilization failure.
Universal sterilization means that all reusable instruments and handpieces are sterilized (rather than just disinfected) between patient uses. This provides the highest level of patient protection. If an item used in a patient’s mouth cannot be sterilized, cannot withstand the conditions of sterilization, or cannot be prevented from becoming contaminated during use, the item should not be used or should be discarded after use on one patient.
Maximum patient protection with universal sterilization can be achieved only by practicing sterility assurance. Sterility assurance is correctly performing the proper instrument processing steps, and monitoring the sterilization steps with biologic, mechanical, and chemical indicators.1
Biological indicators (BIs) are the most accepted means of monitoring the sterilization process because they directly determine whether the most resistant microorganisms (e.g., Geobacillus or Bacillus species) are present, rather than merely determining whether the physical and chemical conditions necessary for sterilization are met. Because spores used in BIs are more resistant and present in greater numbers than are the common microbial contaminants found on patient care equipment, an inactivated BI indicates that other potential pathogens in the load have also been killed. Correct functioning of sterilization cycles should be verified for each sterilizer by the periodic use (at least weekly) of BIs.2
Mechanical techniques for monitoring sterilization include assessing the cycle time, temperature, and pressure of sterilization equipment by observing the gauges or displays on the sterilizer. Some tabletop sterilizers have recording devices that print out these parameters. Correct readings do not ensure sterilization, but they could be the first indication that a problem occurred with the sterilization cycle.
Chemical indicators, internal and external, use sensitive chemicals to assess physical conditions, such as temperature, during the sterilization process. Chemical indicators, such as heat-sensitive tape, change color rapidly when a given parameter is reached. An internal chemical indicator should be placed in every sterilization package to ensure the sterilization agent has penetrated the packaging material and actually reached the instruments inside. An external indicator should be used when the internal indicator cannot be seen from outside the package. Single-parameter internal indicators provide information on only one sterilization parameter and are available for steam, dry heat, and unsaturated chemical vapor. Multiparameter internal indicators measure two to three parameters and can provide a more reliable indication that sterilization conditions have been met. Multiparameter internal indicators are only available for steam sterilizers (i.e., autoclaves). Refer to the manufacturer’s instructions for proper use and placement of chemical indicators.
Two ways to process the biological monitors are in-office monitoring and mail-in monitoring. In-office monitoring systems are available for purchase and currently provide only testing for steam sterilizers. Mail-in monitoring services are for any type of sterilizer and are available through private companies and some dental schools. The mail-in system consists of BIs (usually spore strips) and instructions for use. After processing the BI through the sterilizer, it is mailed in to the service. A report of the results is sent back to the dental office. In the event of a sterilization failure, immediate action must be taken to determine the reason for the failure. Also be sure to take the sterilizer out of service until the cause of failure can be determined and corrected. Any items processed since the last spore test may not have been sterilized, so they need to be repackaged and resterilized in a properly functioning sterilizer.
Next month’s article will include information on how to identify the cause of sterilization failure.
Author bio
Leslie Canham is a dental speaker and consultant specializing in infection control and OSHA compliance. She has more than 36 years of experience in dentistry. Canham is the founder of Leslie Canham Seminars, providing in-office training, mock inspections, consulting, and online seminars and webinars to help the dental team navigate state and federal regulations. Reach Canham at (888) 853-7543 or Leslie Canham.
References
1. Miller, C. Infection Control and Management of Hazardous Materials for the Dental Team. 4th. Canada: Mosby Elsevier, 2010. 138. Print.
2. "Infection Control in Dental Settings-Sterilization Monitoring." Centers for Disease Control and Prevention. Np. 14 Oct 2009. Web. 20 March 2011. http://www.cdc.gov/OralHealth/infectioncontrol/faq/sterilization_monitoring.htm.
