I just looked at a small tube of Crest that I had left in a pencil box of travel supplies somewhere between 1982 and 1988, and it still seems to be good. No mold or anything.

Baking soda is okay if you don't have sensitive gums or problems with receding gums. It's pretty gritty.

To tell the truth, you don't really need toothpaste -- it's the brush that does the work. Toothpaste just provides some flavor that is adequate to keep you brushing and leave a little minty freshness, and most kinds provide some fluoride, which is usually the only "active" ingredient. Brush your teeth, brush your tongue, and no one will know you didn't use toothpaste unless they were specifically looking for the scent. (personally, I'd stay away from those people.....)

Sue