This patient presented with a porcelain-fused-to-metal crown on the maxillary left central incisor. There was recession at the margin of the crown exposing the metal collar. The porcelain was poorly matched to the adjacent natural teeth resulting in what I call the "Beacon" effect where the restored tooth shines out at the observer as a beacon in the night.... In other words, it is very obvious to everyone that this is a false tooth!

You should note that practically everything is wrong with this crown. The color is poor and the texture is poor. Even the over all shape of the crown is very much different than the natural central incisor. We know that color can be off slightly and still yield a result that is pleasing to the observer. But, when shape and texture are incorrect, the differences become glaringly obvious.