E.L.
Bummer! I worry about this too and am so sorry you have another thing on your plate to make you uncomfortable. ugh. I am pretty sure that the ADA recommends that pregnant women avoid dental work in their 1st trimester. I believe the 2nd and 3rd are alright, but you can go on their site, or go to http://www.americanpregnancy.org/ and see what they say.
Good luck!