sterilizers. Monitor and record at least weekly the temperature in the sterilizer well. If using salt in place of beads in the sterilizer, line the well with aluminum foil to prevent corrosion. CRITICAL CATEGORY ITEMS REQUIRING  STERILIZATION All critical category items require sterilization. Table  10-3  lists  a  variety  of  different  dental instruments and materials and shows what type of sterilization or disinfection is effective and preferred for each particular item. It also lists methods that are effective  and  acceptable,  effective  but  risk  damage, and  ineffective  with  risk  of  damage  to  materials. Sterilize critical category items before turning them in for service or repair. Following  BUMEDINST  6600.10,  sterilize critical category items as follows: Surgical  instruments—Effective and preferred methods of sterilization are the steam autoclave, dry heat oven, chemical vapor, or ethylene oxide. Handpieces—Handpieces  include:  low-speed motor  attachments,  sonic  scaler,  and  tips.  Follow manufacturer’s  instructions.  See  table  10-3,  for recommended  method  of  sterilization.  Follow manufacturer’s  instructions  for  the  cleaning  of  the  fiber optic bundle. Burs  and  diamonds—Clean burs and diamonds and dry before sterilizing. Many burs and diamonds are used only for single patient use. One accepted method of sterilization for burs and diamonds are to place them in a screw cap glass test tube (fig. 10-13) or an aluminum foil wrapped bur block and dry heat sterilize for 90 minutes at 320-345°F. Place a chemical indicator in each tube or wrapped bur block. At least weekly, place a biological monitor in one tube or foil wrapped block during the first load of the day,. retrieve and  send  for  culture  testing  following  the manufacturer’s  recommendations. Endodontic files and Gates-Glidden burs— Arrange sets in file blocks and seal in peel packs before autoclaving.  When  additional  files  or  burs  are necessary, take them from a new package or from a file storage box and sterilize them in a bead or salt sterilizer before use. Use endodontic broaches once and discard into a sharps container. Dental Technician, Volume 2, NAVEDTRA   12573,   chapter   7,   illustrates   and explains  endodontic  broaches. 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, 10-14