A 50 year-old patient presented with a chief complaint of “my tooth is throbbing.” She said that she had the root canal done about 20 years ago. Periapical x-rays of #19 showed a previously treated root canal with 3 treated canals that were filled short of the apices and a periapical radiolucency around the distal root.
It was decided that a CBCT scan of #19 was needed for further evaluation. The following scan shows a sagittal view with a missing 4th canal – DB canal.
This can also be seen in the axial section:
After discussing the findings with the patient, re-treatment of #19 was decided as the treatment of choice. After removal of the gutta percha, the DB canal was found with its own portal-of-exit.
All canals were instrumented, cleaned and filled to the apices. The post-op film is shown below.
This case shows that the conebeam is a very helpful diagnostic tool in identifying the etiological source of a painful tooth for a patient.