Mix all of the ingredients in a bowl. Use a fork to mash any clumps and mix in any essential oils (if using).
Store in a small glass jar with a lid.
To use, place some powder in your palm and dip a wet toothbrush into the powder. Brush and rinse.
Notes
You can customize the powder to your taste and all of the herbal ingredients are optional. Create your own flavor with the herbs and essential oils of your choice.