Tales from the Chamber:
A Pair of Kase’s Cases

Doug Kase
 
 

FIGURE 1: A radiograph from a mesial angulation reveals the possible existence of a secondary root or canal on tooth number 28.	FIGURE 2: Access into the buccal canal achieved through a centrally located orifice.

    After additional excavation toward the lingual, I was not able to find an additional orifice for the lingual canal.  When excavating for an additional canal it is most important to keep in mind the external anatomy of the root to avoid a perforation.  So by placing a 45-degree bend at the tip of a number 10 reamer, I was able to find a catch on the lingual wall of the main canal about 4 mm from the apex.  The radiograph (Figure 3) confirmed that I was dealing with a bifurcated canal.  I instrumented the lingual canal, using plenty of RC Prep and irrigation.  An apical bend in all of the instruments helped to re-negotiate the apical anatomy.  It is also important to continually check the already instrumented buccal canal to make sure that you do not block it with debris.
    The case was obturated using the EZ-Fill technique.  I placed EZ-Fill cement into the canal with the EZ-Fill cement spiral and inserted a medium gutta-percha point to the apex of the buccal canal.  Note on the radiograph (Figure 4) the movement of cement into the lingual canal caused by the lateral force generated by the cement spiral and the lateral pressure occasioned by the placement of the gutta-percha point.
 

FIGURE 3: Radiograph confirms that the canal is bifurcated.	FIGURE 4: Note the movement of cement into the lingual canal.

    Due to the widened common coronal two-thirds of the canal, I was able to use a number 25 finger plugger, not for apical condensation, but to move the coronal mass of gutta percha against the buccal wall and to create a passageway for my lingual gutta-percha point.  A small curve was placed in the apical end of the plugger to facilitate its passage into the lingual split.  I used a plugger rather than a reamer to make sure not to pull out the buccal fill (Figure 5).  I did an immediate post prep, and thus the final product (Figure 6).
 

FIGURE 5: Using a plugger rather than a reamer left the buccal fill undisturbed.	FIGURE 6: The final product.

    The next case was also a two-canal bicuspid, but the canals diverged at a more coronal level.  With a second angled radiograph, it was easier to see the divergent canal architecture (Figure 7).  This case was referred to our office because the referring dentist thought that he had perforated with an instrument out the mesial aspect of the root.  This tooth had a centrally located common canal, but it split off into two canals at a higher point than the canal in the first case did.  What the dentist had actually done with his instrument was to locate the lingual canal and negotiate it rather than perforate the tooth (Figure 8).  The apex locator indicated a short measurement of this lingual canal, which corresponded to the location of the radiolucency on the mesial aspect of the root.  I instrumented this canal and then initiated excavation for the buccal canal.
 

FIGURE 7: The divergent canal architecture of a two-canal bicuspid.	FIGURE 8: Showing that the tooth had not been perforated.

    By opening the common canal with a number two Peeso reamer, I was able to use a fine Spartan ultrasonic diamond tip to further widen the buccal aspect of the common canal.  With a 45-degree bend in a number 10 file I was able to snake it into the buccal canal orifice (Figure 9).  I instrumented this canal fully while also making sure that there was continuous access to the already instrumented lingual canal. The canals were filled using the E-Z Fill technique.  Note on the final radiograph the puff of cement from the lingual canal toward the mesial-lingual at the same level as the radiolucency (Figure 10).
 

FIGURE 9: A number 10 file snaked into the buccal canal orifice.	FIGURE 10: Note the puff of cement from the lingual canal toward the mesial-lingual.

    It is extremely important to examine both radiograph and root morphology when dealing with a suspected bifurcated canal in any root.  Mandibular first bicuspids commonly have two canals (approximately 21 percent) with quite a bit of variation in the location of the lingual orifice.  Please take an extra working radiograph if you have to so that you can confirm its existence.  Remember what Doug Kase told you: The canal that forks like a snake’s tongue toward the front of the mouth can be a big pain in the rear.