I'm sure I'm clenching my jaw at night...my top and bottom back teeth hurt I'm going to the dentist on Thursday and I'm scared he'll find some damage and say he has to pull my teeth! I'm so scared of getting a cavity (I've never had one)! Is it really true that pregnancy takes the calcium from your teeth!? I hope I'm just being silly. I brush my teeth almost twice a day now that morning sickness has stopped.