<<Disclaimer: Verify this information before applying it to your situation.>>

I had questioned the role of Ultra-Brite in what seemed like a
gluten-type reaction, despite the fact that Ultra-Brite is listed as GF.
 In asking the list if anyone else had had similar experiences, I
received a few responses.  Despite the GF status, it seems that
"whitening" toothpastes were problematic to a few people, and symptoms
resolved once they switched toothpastes.  One person mentioned that she
had a reaction when using Colgate (GF), but symptoms resolved when she
switched to Crest (GF).  One person reported that the family dentist
recommended against the use of whitening toothpastes, as they can result
in getting "white spots" on the teeth.  One person recommended Tom's of
Maine and Arm & Hammher Dental Gum products.

Latimer
NYC