In our rush to adopt Ni-Ti rotary instrumentation, we often ignore the fact that canal something cannot be “rounded out” by application of tapered instruments to the canals space.
A 48 year old male patient arrived with a history of previous sharp sensitivity to chewing and cold stimulus. Examination of the mandibular right second molar showed mesial and distal marginal ridge cracks that likely ran under the existing occlusal amalgam. Cotton roll tests were positive to chewing upon release. Cold tests showed elevated responses. Heat tests were normal. Periodontal probing was also normal. Periradicular radiography showed no frank pathology. A diagnosis of irreversible pulpitis secondary to M-D crack was made. I noted the fused M and D roots.
Upon access of the tooth, the pulp was found to be vital. I suspected that the canal system might be a “C shape” , which is not uncommon in mandibular second molars. My initial working length files all seemed to go to one place regardless of how mesial or distal they were placed in the C shaped orifice. (Fig.3)
Closer examination of the image showed two distinct apices and I was concerned that I was not getting my files into the more mesial of the two apices. I rebent the hand files and eventually managed to place them into this ramification, but not as consistently as I would have liked. The files simply preferred to take the “easier” path to the distal foramen.
Conservative se of Gates Glidden burs opened the coronal aspect. Care was taken not to over-enlarge this area because of the likelihood of stripping in the thin area of the buccal groove that represented the fusion of the roots.
Figure 4 shows the cone fit and sealer film. Large GP cones were softened with a chloroform dip technique. I noted that the mesial cone was far short of where I wanted but I was confident I could move the warmed gutta percha into the mesial orifice with application of the right amount of heat and obturation pressure.
The final film ( Fig.5) shows that there indeed was a second mesial orifice and that my hand instrumentation technique apparently allowed enough irrigants into the area to remove the tissue and fill the canal system. Proper application of hat and pressure allowed for filling of both apical portals of exit and yielded the classic “Curtain” shaped canal space that is characteristic of C shaped molars. Although the central area of the fill looks less dense, this is in fact where the thinnest part of the “C” is located and is a normal appearance for a case of this type.