Baking soda is actually very safe for teeth. You need to get the kind that is for baking, not for cleaning, which has bigger particles. You can look on the side of the box and it'll say "for baking, cleaning, and antacids". The kind you CAN'T use as an antacid or says "Cannot be used as a dentrifice," is the one you should stay away from - that's used for major cleaning. The particles are bigger so that it doesn't dissolve as much in water and so it pours freely from the container like regular AJAX or Comet or other cleaners, and even table salt does, and doesn't clump in the bottle.
If you dip a wet brush in baking soda and then brush your teeth with baking soda, it does not hurt the enamel at all. It breaks down into really small particles that actually get in between teeth too. It's actually less abrasive than the other abrasives used in commercial toothpaste like hydrated silica and it breaks down better than calcium carbonate (chalk).
The term "abrasive" can be a noun or an adjective, so don't be confused. Silica, baking soda, calcium carbonate, kelp, seaweed, mica, etc are considered abrasives in toothpaste, but not all of them are 'abrasive' and ruin teeth. Tom's of Maine is a company that uses least abrasive abrasives out there, one of which is baking soda.
http://www.tomsofmaine.com/toms/ifs/...icarbonate.asp
The point of having an abrasive (rather than just swishing with some mouthwash) is to get into the tiny ridges in your teeth and scrape off plaque and to get in between teeth where your brush may not reach or where people are negligent about reaching. Also, soft and medium brushes are the best to use, never, ever hard bristles. Add to that - if you find that your brushes are splayed wide apart after using for a while, you're brushing WAY too hard.
Baking to baking soda. Baking soda also reduces the pH of your mouth so that plaque acids don't attack your teeth. It's a very good choice actually.
You can add peppermint or tea tree oil to your baking soda for added breath freshness and antibacterial properties. Don't swallow.
I'm pretty much parrotting a lot of articles I've read on this subject, because I wondered if baking soda was harsh for my teeth as well and I was happy to find that it's not. There's a lot of dentists that actually recommend baking soda for keeping plaque acids down and because people really enjoy brushing with baking soda and baking soda toothpastes, which encourages them to brush longer.
http://www.drbunn.com/tthpste.htm
Per this site, from a dentist's perspective:
"Baking soda is very low on abrasion (even plain baking soda is less abrasive than Crest or Colgate). It's primary function is to kill bacteria; however, at least 26% baking soda is required. Only Arm & Hammer Multi-Benefit Peroxicare toothpaste has enough at 51% (the only toothpaste I recommend)."
Out of the Arm and Hammer line of toothpastes, I use the DentalCare, since it does not have silica and it has the least amount of ingredients out of all the Arm and Hammer products.
There was another few posts on homemade toothpaste recipes, but of course we HAVE NO SEARCH FUNCTION, and looking it up via google or yahoo doesn't always work....