c. Critical Nondisposable Items. Critical nondisposable items, such as
surgical instruments, are able to penetrate tissue or bone and must be sterilized.
Another example is an endodontic file.
d. Noncritical Items. Noncritical items, such as lamp handles and cabinet tops,
that do not come in direct contact with the patient are wrapped with plastic wrap or
aluminum foil and changed after each patient. Items touched by hands during treatment
require careful attention and disinfection before treating each new patient.
Heat is the most practical and dependable method of achieving sterility. This
method of sterilization should be used in preference to room temperature chemical
means. Dry heat is effective for sterilization but usually takes longer. Burs and
endodontic instruments are sterilized using dry heat or chemical vapor under pressure.
See figure 2-1. Glass bead heat transfer is used at chairside to sterilize the files and
the small instruments used in endodontic treatment, but only for one patient at a time
and not for use on other patients.
Increased time for
Figure 2-1. Comparison of various modes of heat sterilization.
STERILIZATION BY THE AUTOCLAVE (MOIST HEAT)
a. General. The autoclave (pressure steam sterilizer) sterilizes using steam
(moist heat) from distilled water. All packs must be loosely arranged in the trays to
ensure penetration by the steam to the center of the pack. All hinged instruments, such
as scissors and pliers, should be placed with the joints open. Instruments of stainless
steel or carbon steel, plastic instruments, and hard rubber or nylon products can be
sterilized in an autoclave, but steam will rust endodontic instruments or burs.