Blackening on Teeth From Colloidal Silver?

Posting this in several forums where I hope someone might have an answer....

I am not a regular user of Colloidal Silver , I got my husband a spray bottle of it at the health food store to use topically on an area he was working on healing after using a bloodroot paste.

He came down with a cold a few days ago and has been using it as directed, spraying in the mouth. Several of his bottom teeth along the gumline and in what may be some cracking in the enamel are dark gray now. He hasn't done anything different besides the silver, and that has to be what caused it, it happened very rapidly.

Does anyone know why this would happen, and whether it's permanent? It really looks bad! I make jewelry with sterling silver and I oxidize it to get exactly that color, so I'm assuming this is oxidized silver particles stuck in some porous areas of his teeth. Tweet