I did this twice when I had a bit of gum pain and it seemed to help and I used it activated the Humble way but I didnt brush. I still not convinced that it won't erode enamel this way as there are studies that show acidified sodium chlorite can do this, however I am not sure that the duration on the teeth and the concentration or acidification matches up to the Miracle-Mineral-Supplement way
Also I don't know if unactivated it would be effective.
I think if you do this regularly you should brush before using it and only brush the gums with it in your mouth.
It is compared to drinking orange juice several times a day in this study but they do not give the ph of the ASC
ASC is also used as a tooth whitener, in gel I think, which affects enamel hardness but here it is applied for long periods. Studies have been done with it in contact for several hours