Just made a new tooth paste with rose petal powder, cardamom powder, baking soda and coconut oil. It is great!
I was using the baking soda and coconut oil, and recently read a post by another herbalist (Rosalee de la Foret) who uses rose petal powder alone, so I combined them. It is also very inspiring for me, thinking about all the other herbs that would make great tooth powders: thyme, cinnamon, clove, sage, mints, etc.
Here's the recipe I put together (approximate):
Rose petal powder 2 parts
Baking soda 1 part
Cardamom powder 1 tablespoon (this will vary depending upon your total amount)
Coconut oil enough to make a paste
I made an 8 ounce jar, with a wide mouth lid, and just dip my wet toothbrush in it.