I have a black crown edge which doesn’t look good. Is that normal?

If you had periodontal disease with increased pocket depths, most of the healing of those pockets happens through gum recession. The gum position rides up the tooth a little and tightens on the root again.

But don’t worry… It’s far better to have shallow pockets and the disease stabilised. This is normal.

In doing so, if the join between the crown and your tooth is now noticeable, replacing the crown is likely to be the best option. From your description the existing crown could either have a metal base (this is quite common for some types of crowns as it is the method established for many decades) or it could have decay around the edges.

Either way, we recommend you explore replacing your crown with an all-porcelain crown (which has no metal base) if suitable for your tooth.