single-ended instrument or as a double-ended instrument, shown in figure 4-14.
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 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 patient.
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 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.Continue Reading