If your having a tooth colored crown custom made it could be a porcelain and metal crown or the new technology available today, it could be all porcelain crown, to have enough strength to stand biting forces, porcelain crown used to be always built upon a metal core.
If you ever notice dark blue at the edge of the crown, now you know what causes it, the metal inside the porcelain.
Now new breakthroughs and adhesive make stronger porcelain materials that now make it possible to make crowns entirely out of porcelain which can then be bound to the teeth.
All porcelain crowns maintain a translucency that makes them hard to tell from natural teeth, without metal the problem from a dark line on the edge of the gum is eliminated, this allows to place the edge of the crown above the gum line and that’s healthier for your tooth and gums. When you want to improve your smile all porcelain crowns are a beautiful and natural looking choice.