Fluoride to build healthy teeth for baby?

This apps information is really questionable how can a toxic waste product help aid teeth? Fluoride has done nothing for my teeth. In fact I was obsessed with brushing and I got a ton of cavities. I got a fluoride filter and my brain fog has lifted. Fluoride is not healthy especially in the uncontrolled amounts in the water. The more water you drink the more fluoride you drink. It is so ridiculous! Always do your own research. This app is questionable.