Most brands won't print their concentration. Here's why that number matters more than the ingredient itself. In the last couple of years, nano-hydroxyapatite (nHA) has gone from a buzzy new ingredient to a clinically studied alternative for those looking for fluoride-free oral care. Every year, more brands are releasing new toothpastes that promote nHA as their hero ingredient. However, while most nHA toothpastes look nearly identical on the front of the tube, the real differ