Review title is Beware! Be careful!!!! [SEP] Wow! Please be careful with this. I did as instructed at 45 degree angle and this left a grayish stain/mark on my tooth. Once I was finally able to remove the stain with floss and electric toothbrush, I found that it left a track down my tooth as if I had used a chisel and it also left a bunch of little dots as if I had picked at it. I will post pics of my tooth once I get a good close up. If you have sensitive or fragile teeth, In my humble opinion, I do not recommend. Be extra careful.