Its perfectly safe to have dental work done during pg. It is recommended however that you do not have amalgam fillings (that's the silver ones) placed or removed during pg. There is no problem with having local anaesthatic and x-rays while perfectly safe should only be done if ABSOLUTELY unavoidable.

Having said that I recommend that my patients wait until they are in the 2nd trimester before having any work done. Having dental work done will not cause a M/C but I would not want to be blamed should the worst happen after they'd had an appt.

HTH