I realize this topic is a little old, but I wanted to add something useful in:
"The process of brushing teeth with a baking soda and salt mixture has been around for a long time, and for good reason. It can actually be effective in removing stains, especially with the help of peroxide, making it a good substitute for chemical teethwhitener systems. Baking soda will also help to kill bacteria which causes plaque, and reduce acids which can harm tooth enamel.
Baking soda is safe to use and easily obtained. If you do use a baking soda mixture, brush gently around your gums so you don't irritate them."
My vote would be for baking soda.
