As rare as a hen's tooth!
As a dentist, I see abnormal tooth structure or anatomy sometimes. Most of them are not often to be seen and very few are rare cases. But this one is extremely rare, as a hen's tooth.
From the first picture, we can see the tooth had two dental abscesses. Obviously the tooth's nerve got infection, which can be seen on the x-ray clearly. Also we can see something abnormal on the x-ray - the tooth got an extra root!
After successfully completing the root canal treatment, we discovered three anatomic abnormalities, which made this case extremely rare.
1. It has an extra root. Normally a lower molar has two roots but this tooth has an extra one in between the mesial and distal roots.
2. It has 5 root canals. Most lower molars have 3 canals. Occasionally we see 4 canals. But this tooth even has gone to another level - 5 canals! From microscopic view, we can clearly see 3 canals in the mesial root, one in distal root and another one in the extra root.
3. Very curved canal in the extra root. During the procedure, every time when we pulled out an endodontic file, it was severely bent! The success of the treatment was achieved with great care and patience.
This tooth was a big challenge for root canal treatment and we loved it!
We will review this case in a few months when the patient comes back.