STERILIZATION MONITORING

Any number of factors can reduce the effectiveness of sterilizers. Overloading and improper wrapping can prevent adequate penetration into the instrument surface. Improper timing, temperature variations, worn gaskets and seals, and sterilizer malfunctions can prevent sterilization. Heat sterilization methods are generally reliable and effective. Nevertheless, regular monitoring of sterilization cycles is necessary to detect inadequate process conditions caused by human error or equipment malfunction.

Types of Sterilization Monitors

Commands should base selection of sterilization monitors on reliability, appropriateness to the process, safety, and cost effectiveness. Many types of monitors are available. The three most commonly used sterilization monitors in the Navy DTFs are biological monitors, internal indicators, and external indicators.

BIOLOGICAL MONITORS.\Biological monitors are designed to assess whether sterilization actually occurred. These systems consist of bacterial endospores impregnated in paper strips or sealed in glass ampules or plastic vials.

INTERNAL INDICATORS.\Internal indicators are chemical dyes that change color when exposed to steam, dry heat, or chemical vapor for a specified period of time. When placed inside an instrument pack, they determine whether the conditions necessary for sterilization have been met.

EXTERNAL INDICATORS.\External indicators are chemical dyes that change color upon short exposure to sterilizing conditions. They are generally printed on packaging materials or supplied in tape form and are necessary to distinguish processed packages from those that have not been cycled. External indicators are not sensitive enough to be processed as an internal indicator and should not be used.

Biological Monitoring

After endospore tests are processed through a sterilization cycle, they must be incubated according to the manufacturer's instructions. A pH indicator in the medium changes color when the ampule of endospores germinate and produce acids. This visually identifies a failure in the sterilization process. As a minimum,

Table 10-3.\Sterilization and Disinfection of Dental Instruments and Materials

Figure 10-13.\Burs in glass test tubes.

perform biological monitoring weekly. Figure 10-14 shows a biological incubator with endospore tests.