Dental crown turning blue? What is the cause of this? Is it important to be replaced? (Photo)

It could not be only the crown that needs to be replaced, if you see on the upper area, there is a black stripe, this means that there is not a well adjust of the margins, this can be a bad adjustment and also a tooth problem, from the root, so my recommendation is to have a check up as soon as possible, due to the conditions. Hope tghis helps.

The
“blue” or often times “grey” appearance of a stain under or at the edge of a
crown usually indicates microleakage or bacteria/decay that has seeped under
the edges of the crown. You really should have it replaced before it
extends further underneath the crown. The sooner the better.

1) Did you have a root canal on that tooth? If there was a root canal on that tooth, the discoloration along the gum could be the root discoloration from an old root canal which is absolutely normal. 2) How old is the crown? The discoloration can also be due to the metal showing through the crown if your dentist made you a porcelain fused to metal crown. If so, I would recommend you replacing it with an all porcelain crown. Typically for my patients, if it is in the esthetic zone, I always use a more esthetic all porcelain crown.Hope that helps...