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4. Periodontic and Endodontic Instruments


a. General. In preparing for root canal treatment, the dental assistant should always refer to the patient's record. By doing this, he can go through each step of treatment required and lay out each item systematically before treatment starts. This procedure will eliminate rushing to retrieve materials and make the treatment steps progress smoothly and orderly.

b. Steps for Treatment. The sequence of treatment for the single appointment method of endodontic treatment follows. Review figure 4-15.

  • Anesthesia.
  • Rubber dam application.
  • Making the area aseptic.
  • Access to pulp chamber.
  • Pulp extirpation.
  • Trial radiograph with instrument in place.
  • Calculating exact measurement.
  • Reaming and filing of root canal to measurement.
  • Irrigation.
  • Desiccation.
  • Selecting, sterilizing, and fitting the point.
  • Trial radiograph with point in place.
  • Cementation of point.
  • Sealing of access opening.
  • Final radiograph.

c. Preparing the Root Canal. For the single appointment method of treatment, the dental assistant should remember the above outline or a similar one. In gaining access, he should provide high and low speed burs, No. 8, No. 6 or No. 701, and a pointed green stone. A barbed broach is used for extirpation of the pulp. Two small Luer-lock syringes, 2 to 5 cc, with 18-gauge needles with the beveled end cut off and bent at about 90, are used to irrigate the tooth. One syringe is filled with hydrogen peroxide and the other with sodium hypochlorite (household liquid bleaching agent). Use of medicament varies among dentists. Dappen dishes are kept filled from plastic squeeze bottles and 2-inch by 2-inch sponges are provided to absorb the overflowing solution. Desiccation or drying of the root canal is done by the use of paper absorbent points: Extra fine, fine, medium, or coarse. The endodontic assistant should set out an assortment of paper points for the dentist. A radiograph with the measured instrument placed in the canal is exposed to determine the exact length of the root canal. The dental assistant then should provide a sequential assortment of reamers and files of increasing size. The beginning size is determined by the dentist. The reamers and files should be provided with rubber stops. The canal is instrumented to the stop until clean, white cuttings are obtained. A corresponding size point, either silver or gutta-percha, is selected and trial-fitted. Once the point passes the trial fit, it is ready for cementation. The dental assistant should now be prepared to mix the root canal cement. If the zinc oxide and eugenol technique is used, relatively large portions of powder are added to the liquid and spatulated until a heavy, creamy, nongranular mix is obtained. When the mix is complete, the cement should be drawn up from the mixing slab about 1 inch without separating. This test is done by dabbing the spatula into the mix and drawing it up slowly. The cement is given to the dentist who places it in the canal with a reamer. The point is coated with cement and seated into place.

d. Filling and Sealing the Root Canal. A small mosquito hemostat, 5 1/2 inches, is usually used for placing a silver point in the canal. A silver point pliers is the instrument used to seat the point in the canal. When gutta-percha points are used, cotton forceps are used to place the point. Depending on the technique, a plugger, a spreader, or both, are used to condense the gutta-percha in the canal. In other techniques, both gutta-percha and silver points are used at the same time. A trial radiograph of the root canal filling is taken and, if it is satisfactory, a thick mix of zinc oxide and eugenol or zinc phosphate cement is made and plugged into the access area to completely seal the canal. A number three Ladmore plugger is the instrument of choice for plugging the access opening with the cement.

e. The Multiappointment Method. The sequence of treatment for the multiappointment method of endodontic therapy differs from the single appointment method in that the sequence is interrupted at various stages to allow for drainage of infected material, for changing of medications in the root canal, or to alleviate a lengthy appointment. Medications commonly used in endodontic techniques include cresatin and camphorated paramono-chloro-phenol, which are placed in dappen dishes and then placed into the root canal by using paper points or into the pulp chamber by using cotton pellets. The tooth is then sealed and kept sealed until the next appointment. Occasionally, bacterial cultures are done each time the root canal dressing is changed. Root canal therapy is completed after a negative culture is obtained.

f. Follow-up Appointments. Upon completion of the treatment by either method, arrangements should be made to recall the patient 6 months later for a follow-up radiograph to determine the success of the treatment.

g. Sterilization. Successful endodontics depends greatly upon sterility. Anything placed into the tooth must be sterilized. Hot salt, glass bead, and molten metal sterilizers are used for sterilization of and working endodontic instruments. Broaches, files and reamers, paper points and cotton pellets are submerged in the sterilizer for not less than 10 seconds. The cement slab and spatula are rendered aseptic by scrubbing with alcohol. Gutta-percha points are sterilized in tincture of metaphen, washed with alcohol and air-dried.


David L. Heiserman, Editor

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Revised: June 06, 2015