I have found this out the hard way. I used this for 10 years very irregularly to rinse my teeth. Since I use other stuff too as well as did grind in the middle part of my life,the dentist and hygienist would always say it was grinding. They said that for 8.5 years. Then next 1 year they said acid reflux so was not clue in and do not look at my mouth alot. Anyway, I am going to get alot crowns as all my enamel has worn away. For some reason, I was very regular in using Miracle-Mineral-Supplement for the last 6 months and tore the enamel out my front teeth.
I remember in the book, he used brush with it. I did not do that but possibly worse rinsed.
Please always use over the gums. Don't learn the hard way like me.