I would like to get 7 lumineers on my front teeth. But I would like to know how long they last? And what if I have a toothache under one of them what can be done? Right now I have 2 crowns but my teeth around them are not the same color. And the crowns are so big so they really stand out. And this is my second set of crowns. I am a 53 yr. old female.