Expert: Frederick R. Liewehr DDS, MS, FICD - 12/14/2006

Question
I have an auto immune disease (Crohns) and have for a long time believed that my teeth are weakened by this condition. I recently had two root canals that were painful. The first was a top tooth, first behind the eye tooth. The second was a molar. The first hurt a bit so with more anesthetic the dentist was able to perform the root canal. The nerve was infected to he drained and closed it, then in a second appointment he put in the post. The molar was difficult - the infected nerve was a surprise for my dentist as he thought I just had a cavity under a cracked old filling. The nerve wouldn't freeze so he had to expose it, then inject directly. He drained and closed it, then referred me to an endodontist.

The endodontist gave me lots of anesthetic considering the pain level of the previous appointment, but one canal out of the four was still painful! He tried many different ways to freeze it and finally was successful. He said it was considerably inflamed. He also said that he removed all the nerve from that tooth.

I have to go back and have a Cerac crown put on both of these teeth. The upper one is still sensitive and hurts when I grab it on both sides. Is there a chance that either tooth will be still be resistant to anesthetic because I dont' think I can suffer the anticipation of that kind of pain again!

Answer
The good news, Jennifer, is that after a root canal you have no pulp, or "nerve" left in your tooth, so you should not need any local anesthetic for the crown preparation. If there is a issue placing retraction cord into your gum, a little anesthetic infiltrated into your gum should take care of that, so you should be fine. Some people are more difficult to anesthetize than others; I happen to be one. Just had a molar worked on the other day, and it was not pleasant, as I was never really numb, and the tooth woke up long before the endodontist was finished. It is usually an anatomical abnormality, but since we can't see what we are doing when we try to find the area where we need to deliver the medicine, it is a real problem. What does concern me is that the one tooth does not feel well. There are a lot of reasons why that could be the case, but you definitely don't want to have the crown put on until it feels better. If more treatment needs to be done, a big hole would have to be cut into the crown, and a Cerac crown might very well break in the process. So, make sure the endodontist gets it feeling good before the crown is placed. Do not listen if your dentist tells you that placing the crown will help it feel better - it won't, and it will probably feel worse. True, it is good to get it covered so that you don't break it, but unless you like buying crowns you should wait until it settles down, or someone finds out why it doesn't. Good luck!

Dr. Liewehr