The black colouring likely indicates that there is metal underneath the porcelain part of the crown. The black line you see around the crown was probably not there when the crown was first placed. Over time, chronic inflammation of the gum tissue causes it to bleed easily and recede from the metal, exposing the metal. No longer is it necessary to have metal in crowns or that unattractive dark line as we now offer the latest in full porcelain and CEREC crowns.
What is that black line I see around the gumline of some crowns?
