cerec crown but can still see my old tooth

[zara]

Hi everyone I had a root canal and cerec crown put on my back molar . The cerec crown does not go up to my gum line. I can clearly see my real tooth which has now turned a darker color during the whole root canal decay process. Since it's the back tooth I guess I am not concerned with the color issues but is it supposed to show my real tooth? I have another crown that was a traditional lab crown and it looks great and it goes up to my gums and looks like my real tooth.