Full personal care with totally safe ingredients - oral

The two ingredients are of course baking soda and hydrogen peroxide.  But using them carelessly you can do great harm to your teeth and gums.  Many commercial oral care products contain the same ingredients, safer, but not perfectly.  Some warned that you cannot use the whitening toothpaste for more than a week, and some cautions for whitening mouth wash.

I won't use dry baking soda to grind you teeth whiter.  It has to be a very precise process to avoid grinding your gums.  At most I would spread dry or paste baking soda on the surface of your teeth to apply them effectively, and make them wet for whatever cleaning effect they have on your teeth.

Or you can mix baking soda solution with glycerin so the paste can stay on your teeth, but all baking soda are dissolved.

Baking soda can remove water stains, which is calcium deposits.  But I doubt if it can dissolve your teeth away by just brushing your teeth or rinsing your mouth.  There are whitening mouth rinse that contains baking soda.  The salty taste is a dead give away.  The concentration doesn't really matter as long as you rinse your mouth thoroughly after.

Baking soda will definitely whiten your teeth but a simple rinse could prevent your teeth from getting more and more stains.

Baking soda is slightly alkaline while sugar caused tooth decay is an acidic process.  It might protect your teeth against decay.  But I will still use a fluoride toothpaste for my kids as we don't drink fluoridated water, we have reverse osmosis.

Baking soda is a deodorizer, so it would help to combat bad breath.  Daily rinsing may cure bad breath.  For emergency I would rinse mouth with concentrated solution and then rinse thoroughly.  You can also work baking soda powder gently into the voids of your teeth, to go where your tooth brushed or flossing missed.  And rinse thoroughly.  Although baking soda is only slightly alkaline, I won't suggest to leave anything in your mouth.

Hydrogen peroxide attacks anything organic (living or once living) and then some.  Certainly it will remove most stains.  Certainly it will attack your gums and anywhere in your mouth.  You pay a lot of money at the dentist to protect your gums while remove stains in the most rapid way.  But a diluted mouth rinse should not cause any harm.  Indeed, 3% peroxide solutions are diluted with equal parts of water for mouth rinse, to reduce bad breath, for first aid, and to kill germs.

Somehow concentrated hydrogen peroxide can dig deep into your teeth around the gum line if you don't rinse after use.  So be very careful what you are using and following instructions.

I use daily a mouth rinse made up of at most 1/8 part of 3% hydrogen peroxide solution and 1 part water, saturated in baking soda.  That is suppose to reduce stains, kill germs, prevent tooth decay, and cure bad breath.

I suggest to use whitening tooth paste unless you are prepared to make your own "pure" toothpaste using glycerin.  If you want a boost, you can stick baking soda to your tooth paste.