Expert: Mark Bornfeld DDS - 2/20/2007

Question
Dear Dr. Bornfield,
Around 2/1999, the day after replacing a filling on my #29 tooth, I ended up wiht a root canal and a crown due to extreme pain.  Eversince then, I feel discomfort and pulsing pain occasionally.  I complained to my dentist who said that was nothing wrong with the root canal. I saw another dentist in 2002 and she sent me to a root canal specialist who told me that was nothting wrong with the root canal treatmennt either.  In June 2006, I went to a new dentist who told me there may be a decay under the crown.  She put on a new crown and there was no cavity underneath the crown. But sometimes I feel the same pulsing sensation. Two weeks ago I've gone to another dentist who told me the x-ray showed "an opening on distal margin on tooth #29" and need to redo the crown.
I am concerned is it safe to redo the crown for the third time? Is the pulsing discomfort cause by failure of the root canal treatment in 1999. What is open margin or will it cause any discomfort or pain?
Thanks for your help.
Kat  

Answer
Dear Kat,

Lower premolar teeth are deceptively difficult to treat endodontically (i.e., by root canal therapy). They sometimes have difficult canal geometry, which can complicate efforts to completely clean them out. A possible consequence of this is a failure of the root canal therapy to accomplish its intended goal-- to eliminate infection. This can be the case even if everything looks good on an x-ray, as evidenced by your dentists repeatedly telling you that all is well. Unfortunately, you know better.

However, knowing there is a problem is one thing; knowing what to do is another. I suspect your dentists (both your general dentist and endodontist) wouldn't know how to improve on the equivocal result you now have. So the question becomes whether it makes sense to continue to expend resources of time, effort, and money on this tooth.

Let me say that any decay around the margin of this tooth will have nothing to do with pain, throbbing, or other symptoms. Although it is possible that you have some other problem unrelated to the root canal treatment itself that is responsible for your symptoms (fractured root or periodontal inflammation are two possibilities that come to mind), your guess about a failure of the 8-year old root canal treatment is the most likely to be on the mark.

Nonetheless, if there is margin decay, this can eventually lead to the disintegration and loss of the tooth, so you'll need to decide whether further efforts in the service of this tooth are worthwhile. (As an aside, you should be at least slightly curious why your current crown needs replacement just 8 months after it was placed, since this places into doubt the quality of the service rendered.)

If your symptoms can be conclusively determined to be coming from tooth #29, this may be a good time to decide whether a different strategy might make more sense-- such as extraction of the tooth followed by some type of prosthetic replacement. It may be time to cut your losses, and nobody is better qualified to make that decision than you. After all, you are the one that is in pain, while your dentists can afford to be cavalier about persisting in saving this problematic tooth.

Hope this helps...