Step 1: Ingredients
The basis of homemade toothpaste is baking soda and hydrogen peroxide. Either one in huge doses can be dangerous, so DO NOT INGEST!
Sodium bicarbonate (baking soda) is a mild abrasive and has anti-bacterial properties.
Hydrogen peroxide helps by break down bacterial films with its foaming action. I used a 3% solution, but anything you can find at a local drug store should be ok.
Vegetable-base glycerin liquid lends a nice consistency and sweetness, but is completely optional. You should be able to find this at a drug store, or specialty foods shop, but I got mine online from a soap-supply store.
I definitely recommend using some kind of flavoring. It's totally optional, but adding a drop of peppermint oil will leave your mouth feeling super fresh. Tea tree oil boosts the anti-bacterial properties and tastes good. A few drops of cinnamon oil (my favorite!) will definitely spice things up. Food-grade grape or bubble gum flavor oil may entice your kids to brush more regularly - just be sure to supervise them and make sure they're not ingesting it!
6 parts baking soda : 1 part vegetable based glycerin : 1 part hydrogen peroxide solution : flavor to taste
This makes a nice paste. To make a smoother mix, reduce the soda. To omit the glycerin, increase the peroxide.
Most over the counter hydrogen peroxide solutions are not suitable for ingestion. Make sure to use supervision with children.