great thread, i think it will help alot of people...i hadnt heard of the toothpaste and gels like the ones mentioned and that is worth looking into..
not sure if this has anything to do with your tooth enamel loss but wanted to mention in case it might....one of my kids went for cleaning etc. and was told that they could tell by looking at her irritated gums that she was allergic to something in her tooth paste and to try different ones, they said a sign is when you brush and have like a "slimey" residue when you spit out, or that irritates the gums, which my child said she had both but didnt think to mention it...again may or may not have anything to do with enamel but just wanted to let you know in case it does, we had no idea that you could be allergic to something in a tooth paste but it makes very much sense once it was said....and we switched toothpaste..
take care,