I use a toothpaste from Melaleuca, and its really good. A friend of mine told me she uses toothpaste from her local health food store and it actually helped enamel grow back on her daughter's tooth that the dentist was going to do massive work on. When they went to get the second check-up for it, he said, "oh, this isn't nearly as bad as i thought it was, it won't be that big of a job after all". And, she swears it was using that toothpaste that made the big difference. I think there is a warning on some of those whitening kits that if you have teeth that are not "sound", don't use it, as it will affect the enamel and cause you problems. I haven't done this yet, but the old way of whitening teeth is to take a capful of peroxide while you are showering or bathing and squish it around in your mouth and then rinse real well.