tetracycline products have long been known to damage healthy gum tissue. it doesnt destroy it, but leeches into it, and causes it to change color. From tan to grey and even dark grey. it cannot be bleached, or repaired once it happens. its something to be on the lookout for with children when they take those products as their teeth are still active and growing, and will suck it up quick.

A waitress in a local diner has tetracycline stained teeth. She said she never wants to smile, and always feels self conscious. It happend when she was 25