Replied by Larry Post (Australia) on 08/05/2022
I don't use it as a mouthwash, I drink it in water, have done for years. Makes a whole world of difference to an arthritic joint. Only small amounts are needed, like what you can pick up with a toothpick, although people do take much more without problems.
It's illegal in many places to sell it for human consumption, but it is quite safe. The ban was mainly because it threatened the HUGE arthritis industry.
But as a mouthwash, why not? Whether it will help with cavities, I can't say, but it certainly won't make matters worse.
Do let us know how it goes.