1-20. INSTRUMENTS FOR LOCAL ANESTHESIA
a. Anesthetic Syringe (SYRINGE, CARTRIDGE). The anesthetic syringe (figure
1-15) is designed to support and expel anesthetic solution from a commercially prepared
glass cartridge called a CarpuleTM. (The trademark name is Carpule.) The cartridge
syringe available for local anesthesia has a thumb-ring handle at the outer end and a
harpoon at the cartridge end of the plunger. The harpoon is designed to engage the
rubber stopper plunger of the cartridge. The thumb-ring is used to draw back on the
plunger to determine whether the needle has penetrated a blood vessel. This procedure
is called "aspirating" and the syringe is an aspirating syringe.
Figure 1-15. Anesthetic syringe (aspirating).
b. Disposable Needles (NEEDLES, DISPOSABLE). Disposable needles are
packaged to keep them in a sterile condition. Once used, they are discarded. They are
attached to the syringe by a plastic hub that is part of the disposable needle. They are
supplied in lengths of thirteen-sixteenths of an inch and one and three-eighths of an inch.
Disposable needles are always sterile, always sharp, and less likely to break than other
needles. Hypodermic needles should be disposed of in such a way that they cannot
injure clinic personnel and will not be available for pilferage or theft.
1-21. ANESTHETIC INSTRUMENT SETUP
a. Sterilized Instruments. As in the basic examination, the anesthesia also
requires a certain setup. (Look in Annex A for typical instrument setups for various dental
procedures.) One instrument in the setup that always requires autoclaving is the syringe.
The other items are sterilized by the manufacturer and packaged in this condition.
b. The Topical Anesthetic. The first item in the setup is topical Xylocaine. This
anesthetic is produced in a jelly-like or ointment form. It is most often used to anesthetize
the area where the actual injection is to be made. Two-inch-by-two-inch gauze or cotton
tip applicators will be necessary when administering topical Xylocaine. A small amount
is placed on the applicator and applied over the area to be injected. The purpose of this
topical anesthesia is to lessen the discomfort to the patient during the actual injection.