I found just of that one tooth. Please let me know what you think. Thank You
That helps a lot! It looks to me like one of two things. You either have a failing root canal or there are gum problems in between the roots of the tooth. When you had your examination, if you had any gum problems elsewhere, I would start by dealing with them and rule this area in or out for any complications due to gum issues.
It is also possible that there is a root fracture. Usually, when it is just a failing root canal, the dark area tends to focus just around the very end of the tooth. In your situation, the dark area goes down the root and is starting to reach all the way to the center of the tooth. With careful examination and probing, it is often possible to diagnosis a fracture, but it may take a specialist to do that.
If there are no gum problems, then I would most likely suggest redoing the root canal first and if that did not solve the problem, do surgery on the end of the root which would also allow me to see visually what is going on. All this has a chance of not solving the problem. Another option would be to remove the tooth and place a bridge or implant. The tooth behind it looks like it will need a crown and maybe a root canal, so 1/3 of a bridge would already be paid for. A CT scan could be a benefit, but only after a very careful gum exam was done in the area. They can also be quite expensive.
You have a difficult situation to make a firm diagnosis. In situations like this, it means eliminating possibilities until the solution is found. Time and money often have a big influence on these types of decisions...it's a tough one.
Hope this helps some anyway. Write back if you need clarification on any of this.
Gary Backlund DMD, MSD