Custom Fitting Gutta Percha cones with the Solvent/Impression Technique
The warm Gutta percha technique is based upon intimate three-dimensional adaptation of the filling material (and sealer) to the canal system. In cases where root anatomy demands prepared canals that are thinner than Non-Standardized Gutta percha cones, they are sometimes "cold rolled" between two glass slabs to make them less tapered. Occasionally the prepared canal shape will not lend itself to the use of "Nonstandard" Gutta percha cone. Such cases include those with larger apices, internal resorption, apical bifidities or those in which the standard "tugback" of the Gutta percha cone is not possible.
To ensure better adaptation of the gutta percha cone, Chloroform is used in a 2-second dip technique. (Such a technique was described some years ago by Fava et al in the JOE) The cone is dipped in a small vial of chloroform (available from JS Dental) and then fit into the canal. The cone is inserted and removed a few times in order to take an "impression" of the apical portion of the canal. It is important to remove the excess chloroform by rinsing the cone in alcohol and drying it with an air syringe for a full 30 seconds. Excessive chloroform present in the Gutta percha cone can result in shrinkage of the filling material and loss of Gutta percha integrity. Both of these problems can affect apical seal. The intimate adaptation of the Gutta percha to the canal walls means that caution must be used when applying sealer. Excessive amounts of sealer can be hydraulically extruded during insertion of the point if too much sealer is used. Pack the case as usual.