INFECTION CONTROL

The US Centers for Disease Control and Prevention (CDC) recommends that correct functioning of sterilization cycles should be verified for each sterilizer using a biological indicator (BI) and control at least once a week.¹Virtually every state has taken this quality control recommendation from the CDC and turned it into a requirement for most healthcare settings, including dental practices. In addition, loads containing implantable devices should be biologically monitored, and the items quarantined until BI results are known. The importance of routine biological monitoring cannot be overemphasized, as BIs can ascertain the effectiveness of many of the steps involved in instrument reprocessing. Sterilization procedures are routinely monitored using a combination of mechanical, chemical, and biological indicators. Taken together, these indicators evaluate the sterilizing conditions and effectiveness of the process. Because BIs directly monitor sterilization by assessing the processes’ ability to kill known highly resistant bacterial spores (eg, Geobacillus or Bacillus species), rather than only testing the physical and chemical conditions necessary for sterilization, the use of calibrated BIs remains the accepted “gold standard” for monitoring. 

Although multiple studies have shown that the most common cause of sterilization failures is human error, other problems can compromise sterilizer efficiency. A few common errors are listed in Table 1.

We have seen advertisements that tout the use of “faster” sterilizers; how are they different from the standard autoclave and what are the advantages of “faster and better”? 
If you are using an autoclave like the overwhelming majority of dental practices, you probably have been using a gravity displacement autoclave. This type of unit has been available for more than a century and sterilizes with self-generated steam that is created within the chamber or by a component steam generator. Because air entering the chamber mixes with air, cool air pockets can form within the chamber, which may result in extended times for sterilization of certain items. In addition, overloading this type of autoclave can lead to incomplete drying of sterilized instrument packs, resulting in the user commonly finding wet packages at the end of the cycle. Modification of later generations of autoclaves has resulted in some sterilizers using pressure-pulsing techniques along with gravity displacement techniques to assist in removing air from the chamber before the sterilization cycle.
Development of a new generation of autoclaves within the last 2 decades has added a new dimension to this heat sterilization modality. These autoclaves are classified as “Class B” sterilizers or “pre- and post-vacuum” steam sterilizers. The equipment is fitted with a pump that creates an initial vacuum in the chamber to ensure air is removed from the sterilizing chamber before steam enters. In contrast to a gravity displacement autoclave, this procedure allows faster and more thorough steam penetration throughout the entire load. The poststerilization vacuum cycle also is highly efficient because it facilitates drying. Practices that utilize this type of sterilizer frequently report the instrument packs are “bone dry” at the end of the sterilization process.