I'm sorry to say that I've had this problem more than once, with teeth that had root canals. I hope that it's just cement stuck in there, as the dentist suggests - with me, it was broken teeth. I kept the first tooth after they pulled it; it has a crack all the way down one root. If a tooth is broken, it can still hurt even without nerves, because a nerve or two remains at the bottom of the root. I'm on my third implant as a result of brittle teeth. One oral surgeon suggested that root canals were only a temporary (if expensive) measure, making the tooth more brittle and requiring the $4000 implant surgery down the road. Good luck...View Thread