Crowns and bridges are usually made out of porcelain or metal alloys and they will strengthen and protect your teeth as well as enhance your smile. Crowns are placed over your weakened or decayed tooth after they are reduced in size, to allow the crown to fit over the tooth like a thimble. A bridge replaces a missing tooth by placing crowns on the teeth on either side of the missing tooth and another false crown is attached between them to replace the missing tooth. Crowns are extremely durable and require only the same care as your own teeth.