Ask the Editors
How different are fast sterilizers from the autoclave I have used for over 15 years, and what are the advantages of faster and better?
If you are using 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 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 two decades has added a new dimension to this heat sterilization modality. Units have been available in the U.S. for the past few years after having been originally developed in Europe. 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 post-sterilization 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.