Expert: Gary Backlund, DMD, MSD - 12/8/2009

Question
Hi Dr. Backlund,
Thank you for taking the time to answer my question.  A little over a year ago I had to get an emergency root canal while traveling.  I knew I had a problem but wasn't scheduled to get it until after I got back.  Long story short, pain got unbearable and I had to get a root canal done immediately.
Fast forward a few months, the pain starts coming back but MUCH milder.  A dull ache that I can pretty much live with.  Then a few months later and I go back in to get it looked at and it turns out the first root canal failed.  About a month ago, I got it redone.  They didn't put a new crown in, but just filled in on top.  It seems kind of strange to me, but that's apparently their protocol and much cheaper for me.  
To the point.  It has been about a month now, and now I am getting sharp sensitivity in the same tooth mostly from sweet foods.  Eating an apple, chewing gum, or a piece of candy.  It is NOT from pressure, and there is no sensitivity that I have noticed yet from heat or cold, just sweet foods.
Please tell me I don't need to get a 3rd root canal or loose my tooth.  It is the farthest back lower molar if that helps.

Answer
Hi Matt,

I'm sorry you're going through all this. Since I can't examine you, I really can't tell you for sure what is going on. What I can tell you is that the root canal tooth is not the one that is feeling the sweet sensations...there is simple no mechanism in the tooth to transmit sensation from the outside of the tooth to the end of the roots where the nerves are that send these feelings to your brain. When a root canal is done, no matter how well or how poorly, that connection is severed. This is true even if one whole root has been left untreated. Unfortunately, you are dealing with another tooth and it could just be a simple cavity or leaking filling. I would suggest that you get in to see your dentist ASAP so things don't get worse.

Hope this helps....sorry for the bad news.

Gary Backlund DMD, MSD