I have recently got 2 crowns in my front to teeth. The shape and colour were what I was after, so when I was shown in the try on glue, they looked perfect. When I got them permanently stuck, I noticed a slight discolouration on one of the crowns and I think it's the glue underneath being visible. I really wanted these crowns to be perfect, but this slight imperfection is annoying me. Do I have any options?