Fluoride may prevent tooth decay by forming a nanoparticulate layer over the tooth, but this can be achieved by brushing with hydroxyapatite.

“and the reason why it was a waste product because they realized when they kept it in the fertilizer um it would burn the root and and and harm the plant so they said well let's take the fluosilicic acid out um but now we're making tons of fertilizer and we have this big pile of waste so what are we going to do with the waste and um I don't know who I I haven't gotten to the Genesis of who had the bright mind to say hey we we'll sell it to these municipalities and we'll dump it in the drinking water because there is marginal evidence um that you know it can prevent tooth decay um and some of that evidence is weak at best you know forming a nanop particulate layer over the tooth and marginally protecting the aluminum but I I think you get the same thing by brushing with hydroxy appetite or um and just brushing your teeth”