It is a long time I am searching for a way to stop buying toothpaste and do it myself.. I found out recently that a piece of Aloe Vera could replace it and produce some foam if you chew it first and brush with it.. Other ideas to produce your own toothpaste?
You could always grind rocks into a semi-powdery form and use that with water to scrub your teeth. Recommended by 9/10 homeopaths.
I knew a girl who didn't brush at all, and just swished coconut oil, and she said she never had a single cavity. Which is more then I can say. lol