I had a crown placed on #8 following a root canal retreatment. Went to the lab for a custom shade & was initally pleased with the result when my dentist applied the crown. Now that I've seen it in natural light, I'm not sure I like it so much...my tooth appears dark at the top. I'm thinking this is my tooth showing through the crown...It looks like my original tooth so I'm disappointed that I went through all that & paid so much for essentially no improvement. Can anything be done about this?