Although it states it will not work on porcelain crowns it actually did on mine! One of my front teeth is a porcelain crown and I got it before I became a heavy smoker and cola drinker. It yellowed along with the other teeth but somehow the strips brightened it back to its original color.
I have had no gum irritation or tooth sensitivity so far. The strips are easy to use, come off easily and leave no residue. I saw results immediately and am now on my fourth day and the results continue to astound me.
Great product!
