A dental crown is a crown that covers a tooth to restore its original shape, size and strength. The bridge is a combination of plastic. Metal-ceramic veneers, also known as porcelain-metal veneers, have a metal layer and the tooth-colored ceramic fuses to the metal layer when heated. Dental bridges are designed to replace missing teeth by "bridging" the gap between the two remaining teeth. Crowns are attached to the rest of the teeth to hold them in place. A cantilever bridge can be used when there is a tooth on only one side of the gap. A cantilever bridge has two crowns side by side, and only one crown is attached to the missing tooth.