I agree with Kafer_Girl and Snoopea. My GP, dentist and midwife all said that it was likely to be the increased blood flow from pregnancy. If you are unsure though, go to the dentist to get it checked out.

I was also unlucky to get the really, really painful teeth. It felt like I had holes in every single one. Went to the dentist and my teeth were in very good shape, just a pregnancy thing. I forget why they said if happened but geez, at times, I am sure it was more painful that some of the labour pains.