Yeah, it's pregnancy. Before modern dental care, in some cultures, it was said that a woman lost a tooth for every baby. I think it's got to do with how pregnancy depletes a mama's nutritional reserves, which leads me to believe that improving your diet can help a lot. I don't know exactly what you'd add, though; I don't know a lot about it. By supplementing, you mean supplements for YOU, right? I would ask in health and healing.
I had the same issues. So I started taking prenatals (not preg. just nursing), taking calcium, magnesium, vit D and niacin (lots!! make sure it's flush free). I also started drinking milk. All things I had not been doing,throughout 2 pregnacies and bfding. Cavities healed <img alt="" class="inlineimg" src="http://www.mothering.com/discussions/images/smilies/smile.gif" style="border:0px solid;" title="smile">