Stir all the dry ingredients together, mixing well.
Slowly add the Wintergreen Essential Oil drops while sitrring to prevent clumping. (If you find it is still clumpy, blitz in a food processer or smoothie blender for a 30 seconds or so to remove the clumps.)
Store in an airtight container.
To use, wet your toothbrush with water and then dip it into your toothpowder, or mix a small amount with coconut oil before applying to your toothbrush.
You can always swap out the wintergreen oil and use peppermint instead!