I was just coming on here to report the same thing. I been doing oil pulling now with either sesame oil or coconut oil just about everyday. But this last week I noticed a translucent effect along with black lines towards the tips of my teeth. I am not taking any sorta Iodine except kelp. What I find odd is that the marks on my teeth look like where my braces pushed up against when I wore them when I was younger. They almost like like something my teeth absorbed and just held in. I am not sure what to do.