I went to the dentist about four months ago and I was told that I needed a cavity filling between teeth #'s 19 and 20 I believe. It was a very small cavity from what the dentist told me. He filled the cavity, and everything seemed fine for a few weeks. Then one day I am flossing and as I come up I hit an area in between the teeth that is very sensitive, from then on I felt nothing but pain and discomfort in that area of the filling, I went back to the dentist and he filed down the filling and it didn't help. I went back again and had it refilled. It was ok for another few weeks, then the pain once again came back. I went back again and x-rays showed the filling being completely sealed, so he really had no explanation of what was going wrong. He discovered that there was a small air-pocket within the top-lining of the filling right in between the two teeth. So he filled this area and said that I should be good to go. I was still sensitive to cold water on that area afterwards, but it wasn't as painful as it was. This lasted two more weeks and now its back being very sensitive to cold water again and causing me lots of grief. He said the only other option would be to refer me to an endodontist about a possible root canal, but I think I would be against such an idea since the cavity itself was nowhere near the pulp of my tooth and was very small. What could be going on with this tooth??