beware be careful [SEP] wow please be careful with this i did as instructed at 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