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August 2004 – Two Rooted Mandibular Cuspid with 3 Canals
Here’s an unusual case that would have probably never been done properly without a scope.
This 49 yr. old male patient was referred to me for treatment of a mandibular left cuspid. The tooth had been prepared as an abutment for a full arch fixed bridge and was asymptomatic. The bridge had been cemented only a few months previously.
I did not have pre-op films of the tooth before the bridge prep but I understand that tooth was virgin prior to preparation. It appeared to have two roots and a LEO. Under medium power mag (Selier) I noticed slight movement of the tooth under the cuspid LL3 crown margin when examining it with an explorer. Although I didn’t get a classic “air bubble” along the crown margin when I attempted to lift the rest of the bridge, I was sure the bridge had some loose abutments. I used a floss threader, got some floss under the bridge and attempted to lift the bridge off using the solder joint distal to this cuspid. Much to my (and the patient’s) surprise the whole bridge (all 12 units !) came off very easily.
I asked how the bridge had been cemented (perhaps temporarily?) and the patient told me that it had been cemented permanently. I then performed thermal tests on the tooth. The results were negative. My suspicions were correct. Non response from this pulp.(Figs 1&2)
I placed a dam (no anesthetic – I LOVE those cases!) and confirmed pulpal necrosis with a cavity test. I placed files into two canals and then cleaned and shaped them. I see the occasional two rooted two canal cuspid, so I wasn’t surprised about that. (Fig.3)
During my final check of the access/canals I noticed what appeared to be anther orifice in the middle of the two canal orifices. Three canals? In a cuspid ? Sure enough, there was another one, slightly shorter but still there. (Fig. 4.) (No photos unfortunately L This op is the one with the video camera attached to the scope and while the video looks OK in the monitor, the PC screen captures just didn’t show up well.)
Because the access was conservative (by referral request) I wasn’t sure whether I could adequately squirt all three canals and get the results I wanted. So, I decided to use a modified technique. I cone cone-fit two of the canals and then packed the third with a squirt. You can tell which one was squirted by the excess – more than I would have liked but still OK. (Fig.5)
It was definitely a strange tooth and I cannot recall ever seeing a three canal mandibular canine in almost 24 years of practice. This case also clearly illustrates the value of a Surgical Operating Microscope. It is not enough to simply anticipate pulpal and root anatomy. In order for maximum success, you must be able to see the tooth with the necessary level of magnification that allow you to deal with these very small and unpredictable structures.