I'd question her a little more. Dentists also will tell you there's nothing toxic in mercury fillings either! The key words are METAL FREE! Ask her if they are metal free. If she says they are metal free, I'd press a little further with, "So they won't show up on xrays?" Ask WHAT exactly she uses for fillings.
Are you having Amalgams removed? If so does she follow ALL the recommended removal protocols? It may not matter much to you if you're young and healthy and only have one or two fillings, but otherwise I'd be very careful.