Crowns and Bridges are similar but different. A crown is a single unit and a bridge consists of multiple units of crowns stuck together.
A crown is used in many circumstances, to strengthen a tooth, to improve appearance, to create a functional bite, to facilitate future complex dentistry and most often, to repair a tooth that has been damaged to such a degree that a routine filling will unlikely suffice.
A bridge, being a number of crowns made as a single unit, is used to fill gaps where teeth have been extracted.
