Question: I had a crown done on a lower back tooth about 4 months ago and it has been hurting me since.  It seems as if the pain is getting worse and it is becoming more sensitive.  The dentist first told me that the pain would go away and that it was not abnormal for it to be sensitive.   I went back a couple of days ago and he now tells me that it will need a root canal and it will cost $800 more.  I am not happy about this.  Can you give me your opinion on this?

Answer:  I can understand why you are not happy.  I don’t know if you were having problems with the tooth before you had a crown done so this will influence my answer.  I will develop a couple of scenarios that are common and follow up with a possible reason why the pain is present.

Scenario #1–  You went to the dentist and the tooth was feeling fine, but had either a crack, deep filling or deep cavity.  The dentist  said it was cracked, so the crown was done to prevent it from fracturing more.

Reason-  Bacteria can penetrate into the root canal system via the crack, leaky filling or cavity and remain free from symptoms (pain).   The body’s immune system keeps these mild infections under control and therefore pain free.   When the tooth was shaped for the crown this could have been enough to make the bacteria currently in the nerve to multiply.  When the bacteria grow like this the nerve begins to sense pain and a toothache ensues.  The root canal is needed to disinfect the inside of the tooth and to save the tooth.  The root canal can usually be made through the crown and then filled.

Scenario #2  Your tooth was sensitive to begin with, especially when chewing and there was hope that the crown would help to strengthen the cracked part.

Reason- When cracks are present the tooth parts can move independent from each other.  When a crown is made, the parts become unified and the desired outcome is that the pain (especially to chewing)  will be eliminated.  This is effective, but if bacteria transfer into the nerve, pain will follow the crown cementation.

Another reason is that the bite may be high, which can traumatize the individual tooth.  If this is the case a small refinement in the bite may be needed.

When these complications occur no one wins.  Unfortunately, this is usually completely unpredictable by the dentist when the crown is made.  I have had the question posed to me  “Why not do root canals on the teeth whenever crowns are made”? My answer is that  this would be over treatment and completely unnecessary.  My experience is that about 95% of crowns made over living teeth are successful without the need for follow up root canals.  If you have more questions about your specific situation, you can call the office at (586) 573-4500  or e-mail me at

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