Calculating exact measurement.
Reaming and filing of root canal to measurement.
(11) Selecting, sterilizing, and fitting the point.
(12) Trial radiograph with point in place.
(13) Cementation of point.
(14) Sealing of access opening.
(15) Final radiograph.
c. Preparing the Root Canal. For the single appointment method of treatment,
the dental specialist 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 dental officers. 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 dental officer. A radiograph with the measured
instrument placed in the canal is exposed to determine the exact length of the root canal.
The dental specialist then should provide a sequential assortment of reamers and files of
increasing size. The beginning size is determined by the dental officer. 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 specialist 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 dental officer who places it in the canal
with a reamer. The point is coated with cement and seated into place.