commonly used and saves valuable time when exposing radiographs. Metal rubber dam frames must be taken off while exposing radiographs. Remember a risk of contamination can occur while the frame is off.
After the tooth is isolated, the dentist makes an opening through the crown of the tooth to gain access to the pulp chamber and canal. The opening is made through the lingual surface on anterior teeth (fig. 7-16, A) and through the occlusal surface on posterior teeth (fig. 7-16, B). Friction-grip and latch-type burs or diamond stones are used to create the endodontic opening. Sizes vary according to the preference of the dentist and the size of the chamber and canals of the tooth.
After the endodontic opening is made, the dentist will locate the root canals and remove the pulp. Anterior teeth usually have one root canal, but often lower incisors will have two canals. Posterior teeth may have up to four canals of different sizes. Anatomical variations exist among patients; therefore, additional canals may be found. A thin, straight explorer can be used as a probe to locate canal openings within the pulp chamber. The larger pulp canals are easier to locate; whereas, smaller canals are sometimes difficult to locate.
Figure 7-16. - Access to pulp chamber and canal: A. Anterior teeth; B. Posterior teeth.
Once the canals are located, the pulp tissue must be removed. If the pulp tissue is still intact, the thin, flexible, barbed broach is used to remove it. Broaches are considered disposable and should be discarded after one use, since they are subject to fracture after repeated sterilization. If the pulp tissue has disintegrated, it is simply removed when the canal is cleaned and filled.
After the root canals are accessed and the pulp tissue is removed, the root canals are cleaned with an irrigating solution. Irrigation and evacuation are essential parts of endodontic treatment because they assist in the removal of pupal remnants and tissue fluids. The irrigation solution also serves as a lubricant in the instrumentation and enlargement of the canal walls.
The most frequently used solution for irrigation of the root canal is sodium hypochlorite or common household bleach. This solution is a solvent for necrotic tissue, in effective disinfectant to destroy bacteria in the canal, and acts as a bleaching agent. Sodium hypochlorite may be used full strength or diluted with 1 to 2 parts water to reduce the chlorine odor.
A sterile, disposable, plastic Luer lock-type syringe (5 cc to 10 cc sizes) with a disposable, blunt 20 to 27 gauge needle is the comnon instrument used to inject the irrigating solution into the canals. The needle may be bent at an angle to provide access to the canal.
The irrigating solution is injected slowly and gently into the canal to prevent the solution from being forced into the periapical tissue. A small root canal file or reamer can then be placed into the canal and rubbed against the pulp canal walls to produce a scrubbing effect that loosens debris and bacteria. The solution is removed with a suction tip on the oral evacuator. Any remaining solution may be absorbed by placing sterile cotton pellets and paper point into the canal. There are numerous times during endodontic treatment in which you will be required to provide thorough irrigation of the pulp chamber and canals. The following are the most common:
Before the use of intracanal instruments once the root canal is accessed and the pulp tissue is removed.Continue Reading