SINGLE GUTTA-PERCHA POINT AND SEALER

With the tendency to preparation techniques of greater taper, gutta-percha points of matching taper may be used. These fit the prepared canal so well that some operators are using a single guttapercha point and sealer. The only advantage of this technique is its simplicity. The disadvantage is that the majority of sealers are soluble. As the canal will not be fully filled in three dimensions, tissue fluids may leach out the sealer over time. 

This technique cannot therefore be recommended. However, in difficult anatomical cases it may be necessary to create a custom-fitted cone. A slightly large cone is selected and the apical part softened, either by solvents such as chloroform, rectified turpentine or oil of eucalyptus, or by immersion in hot water. The softened cone is fitted to working length with gentle pressure. 

The cone is carefully marked for orientation, and the process repeated until a satisfactory fit is obtained. The cone should then be cleaned of all solvents, and the canal obturated using sealer in the usual way.

LATERAL COMPACTION OF WARM GUTTA-PERCHA

A simple modification to the cold lateral compaction technique is to apply heat to the guttapercha. The softened material is easier to compact and will result in a denser root filling. However, finger spreaders will not retain heat sufficiently for this procedure, and specially designed heat carriers should be used. The instruments illustrated in Figure 8 have a sharp tip for lateral compaction, and a blunt plugger tip for limited vertical compaction of the softened gutta-percha. Electrically heated spreaders are also available.

It is important that the instruments are only gently warmed. If the spreader is too hot it will melt the gutta-percha,

PROCEDURE

1. The canal should be irrigated, cleaned and dried.
2. A master point is selected and fitted to the canal as described above. It should be marked at working length, or grasped securely in endodontic locking tweezers.
3. The master point is coated with sealer and used to paste the canal walls with the sealer, using an in-out movement, before seating the point home into the canal at full working length.
4. A fine finger spreader is selected and the rubber stop set to working length. Place the spreader alongside the master point and compact using firm apical finger pressure only. Leave the spreader in situ for 30 seconds. This is important as continuous pressure from the spreader is required to deform the gutta-percha point against the canal walls and to overcome its elasticity.
5. Select an accessory point with locking tweezers and dip its tip into sealer. Do not leave the points in sealer while working (Fig. 6) as a reaction may occur between the zinc oxide in the points (up to 80%) and the eugenol in the sealer, softening the points and making insertion difficult.

6. This stage is best carried out using two hands. Assuming the operator is right handed, the tweezers holding the accessory point are aligned above the tooth in the right hand, while the left hand rotates the spreader a few times through an arc of 30 40  and withdraws it.
7. Immediately place the accessory point alongside the master point. Any delay willallow the master point to relax and space will be lost. Reinsert the spreader and laterally compact both points.
8. Repeat the sequence using gradually larger spreaders and gutta-percha points until the canal is filled.
9. Remove excess gutta-percha from the canal orifice with a heated plugger, and firmly compact the remaining gutta-percha to seal the coronal access to the canal (Fig. 7).
10. If post-space preparation is required it may be carried out at this stage.
11. If not, a layer of resin-modified glassionomer cement should be applied over the gutta-percha and the floor of the access cavity, completing the coronal seal.