update: well, he thinks I'm grinding my teeth, and bruised one of my teeth. He said it's unlikely to be an absys as there was no decay in the tooth. He put it down to either the stress of being pregnant (altho I'm not stressed ) or the more likely one of my sinuses making me clench my teeth at night. Since I have suffered from sinus headaches during the pg that one makes more sense. So I just have to try and consciously leave it alone and see if it gets better.

As for x-rays etc... he said it really depends on how I felt about it. He said they are pretty safe with the shields and things, but most women opt not to do it. I guess if you absolutely need it done (which I didn't coz he didn't think it would be an absys) it is safe enough. But we didn't go into much detail with it.