A Maryland bridge consists of a metal framework with a porcelain tooth baked on to the front of the framework. The framework then ends up as a false tooth with two metal wings on the side. These metal wings are prepared to have a porous surface so that they can receive a bonding agent, and then the wings are bonded to the back sides of the teeth on either side of the missing tooth. The picture on the right shows how this looks.
There are two main esthetic problems with a Maryland bridge, and both of them have to do with the use of the metal. The first problem is that natural teeth are translucent. Therefore, the metal backing that is bonded onto the back side of the front teeth will cause those teeth to darken slightly, and they will no longer match the color of the other front teeth. If the dentist doesn’t take this darkening into account (and very few dentists do), the false tooth that is replaced will also be slightly lighter in shade than these darkened teeth on either side.
The second problem is that the false tooth is a porcelain fused to metal tooth, and it lacks the natural translucency and vitality of your other teeth. The most esthetic false teeth are those made entirely with tooth-colored materials.