Q. I had a crown placed on my front tooth about 3 years. The tooth was fine but discoloured and the dentist (I now see a new dentist) who did it put a crown on after failing with two attempts at a veneer on that tooth. It has never felt right but as yet haven’t been able to afford to replace it.The gum is slightly raised above the crown and there is a thin ‘lip’ where the crown isn’t exactly against the gum. This has been checked by two dentists who say that the crown isn’t the best, but is fine and shouldn’t cause problems. About a month ago I had severe pain on that tooth and my dentist performed a root canal through the back of the crown.The nerve was apparently sclerosed and it was tricky to find it and get it all out.However, the dentist was confident that she got it all. I was still in pain after that and the dentist went in and cleaned it out again. I’ve had three courses of antibiotics which haven’t seemed to do much. Even though the pain is less, the tooth still hasn’t settled and feels sensitive to touch and throbs sometimes. the gum line at the top is also sore to the touch and causes a throbbing pain. The dentist(who is not my usual dentsit as she was away) says that she will clean it again if pain persists.She finished the root treatment a week ago. My usual dentist says she would have pulled the tooth already. As it is a front tooth, obviously i want to avoid this! The x-rays look fine.What could be going on with the tooth? Is it likely to settle at this stage?