Here's a way :) Tell your customers -- Here is some fluoride to put in your water. It will make your teeth very strong so you don't get cavities. But although it's a WONDERFUL product, and I highly recommend it, it has a few downsides that affect just a few people. (You have to say this with a straight face.) To be sure, buy this iodine as well. It will protect you and your children, and let you have all the benefits of the fluoride.