People looking for an alternative to fluoride toothpaste don’t have to miss out on its protective, anti-cavity effects. Hydroxyapatite is gaining popularity as a toothpaste ingredient thanks to its ability to remineralize teeth and protect against cavities—plus it’s proving to have a few added benefits as well. But as with any “new” ingredient, many people have questions about just what hydroxyapatite is, how it works, and whether it’s safe.