single-ended instrument or as a double-ended
instrument, shown in figure 4-14.
MATERIALS, AND EQUIPMENT
A number of miscellaneous instruments,
materials, and equipment are used in operative
dentistry. Instruments such as dental mirrors,
explorers, and cotton forceps are called a basic dental
set (BDS) and are usually used in all dental specialties.
This syringe is used in dentistry to inject a local
anesthetic. The aspirating syringe differs from most
syringes in that it is designed to inject anesthetic from a
carpule (fig. 4-15). The parts of an aspirating syringe
consist of a threaded tip where the needle attaches, a
barrel where the carpule is placed, a piston rod
(plunger) with a harpoon attached that embeds itself
into the rubber stopper of the carpule, a finger grip, and
a thumb ring (fig 4-16). The harpoon allows the dentist
to aspirate (draw back) the injection site to see if the
needle tip is located in a blood vessel before injecting
the anesthetic solution. Once the harpoon is engaged
into the rubber stopper of the anesthetic carpule, the
dentist can apply inward or outward pressure on the
Figure 4-14.Double-ended calcium hydroxide instrument.
Figure 4-15.Anesthetic carpule.
stopper by exerting pressure on the thumb ring. Pulling
the thumb ring outward also pulls the plunger outward
producing an aspirating effect; whereas, pushing
inward forces the anesthetic solution through the
ASPIRATING SYRINGE NEEDLE
The aspirating syringe needles used in dental
treatm ent arrive sterile and are disposable. They are
designed for a single use, and are available in different
gauges and lengths (fig. 4-17). The gauge of a needle
refers to the diameter of the hollow shaft of the needle.
The larger the gauge, the smaller in diameter the
needle. The lengths of the needles vary, and are
classified as long (L) or short (S).
Each needle has either a plastic or metal hub
designed to screw onto the threaded end of the syringe
(fig. 4-18). This hub is positioned to permit the needle
to extend inward to penetrate the rubber seal portion of
a loaded anesthetic carpule.
The plastic caps covering the sterile needle are
easily removed from both ends. When placing the
needle onto the syringe, remove only the cap that
covers the syringe end on the needle. This maintains
the sterility of the needle portion used to inject the
Normally, you prepare the anesthetic syringe with
a short needle (13/16 inch in length) for maxillary
injections, and a long needle (17/8 inches in length) for
mandibular injections. The tip of the needle has a
beveled angle, which is turned toward the alveolus to
accurately deposit the solution.
RUBBER DAM INSTRUMENTS
Rubber dam instruments include the rubber dam
punch, clamps, clamp forceps, and frame. These
instruments prepare and maintain the position of thin
sheets of latex rubber (rubber dam material). The
rubber dam itself is used to isolate a designated tooth or
teeth in the mouth before certain operative, endodontic
and preventive dentistry procedures are performed.
The rubber dam provides a clean, dry field of operation
and improves the dentists view of the operating site. It
also keeps fluids, tissues, and the tongue away from the
operating site and prevents the patient from
accidentally swallowing or aspirating debris.