Iolite
One of the doctors in the peds practice that I took my daughter to when she was an infant told me to be sure to use tap water when I make up her formula so she would get the fluoride for healthy teeth!!! I knew that was bogus but just nodded. I continued making up her formula with distilled water that I bought every week just for that purpose. Now, at age 12, she has beautiful, cavity-free teeth. She brushes with fluoride-free toothpaste, always has.