I had a cracked tooth which I had a root canal done on. After going to the endodontist several times and being on an antibiotic I was told to go ahead and have the crown put on. This was in April of 2010. I recently went back to my dentist in Septemberfor a regular checkup and complained of discomfort in the tooth I had crowned. He said I had a severe infection under the tooth. My question is why wouldn't the dentists have checked the tooth via x-ray to make sure the infection was gone? The endodontist said I never got rid of the original infection.