I hate the dark line around my front crowns, it wasn’t there when they were first fitted.
You probably have bonded browns and the dark line that you can see is the metal substructure of the crown, onto which the porcelain layer is bonded (hence the name). At the time of fitting this join between the crown and your tooth was probably hidden underneath the edge of the gum. Over time your gum has shrunk back a little, exposing the join line.
The alternative is all porcelain crowns which tend to look more natural as they transmit light in a similar way to normal tooth enamel. In some cases the bite against the lower teeth is so close that only a bonded brown will do the job. We can give you advice on your particular situation.
