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April 2004 – Perforation or Lateral Canal?
A Mandibular second premolar in a 43 year old female patient was referred for endodontic treatment. The patient had a history of deep composite restoration and discoloration in this promolar. Caries was also visible under the distal composite. The periapical lesion was fairly large and the patient said that she had been having problems with the tooth for almost 2 years.
Fig. 1 - Referral's Pre Op
Fig. 2 - My Pre Op
My preoperative radiograph showed a diffuse radiolucency in the apical third. I though this may be indicative of a resorptive lesion or extra portal of exit. Dr. Donald Yu's research has showed that there is a geometric relationship between the position of the Lesion of Endodontic Origin and the portal of exit.
Fig. 3 - Working Length
My initial working length instrument indicated that the tooth had quite a curve at the apical third and frequent rebending of hand instruments was necessary to negotiate it to length. A series of Protaper instruments was used to enlarge the canal space but as I began to try to negotiate this tricky curve I noted that occasionally the file would exit short of the apparent terminus.
Fig. 4 - Cone Fit #1
Insufficient curvature of the GP cone causes it to exit in the acessory canal area.
Because the patient was NOT anesthetized for this procedure ( I generally do not anesthetize patients with suspected necrotic teeth in order to properly perform a cavity test and confirm the diagnosis) she detected the initial #15 file that was used to explore this area. After doing my final shaping I noted that my first Gutta Percha Cone ( not pre-bent very much) exited in this area. I was concerned about a perforation in this area and how this would affect the cone fit in the remaining apical section.
Fig. 5 - Recurving of the Gutta Percha Cone bypasses the acessory and allows placement to the end of the root. Now that the accessory has been instrumented, it shows up more clearly in the image.
Fig. 6 - Downpack with partial Obtura Backfill
Fig. 7 - Final Fill #1
Fig. 8 - Final Fill #2
We will probably never know whether this was a perforation, but from the original appearance of the lesion, its position, the "branched" rather than straightened appearance of the canal fill in Fig. 8, it is likely that this was natural anatomy rather than a "created" canal.
Fig. 9- 6 Month Recall - Sept 2004
NEW Fig. 10 - 1 Yr Recall - May 2005