What is a Crown?

A crown, also referred to as a cap, is a dental restoration that covers the entire tooth, replacing its outer layer of enamel with a new material. A crown is contoured and sized similarly to a natural tooth, and they come into contact with the opposite tooth in a normal way, allowing for food to be chewed properly. In general, a crown should feel like a regular tooth when it comes to function. Depending on the material chosen for the crown, it also can look like a perfectly natural tooth.

What is a Bridge ??

A bridge is a fixed partial denture: it is fixed (glued) to the teeth, it replaces some (not all) of the teeth, and it uses a fake tooth or teeth (denture) in the place of missing teeth.
A bridge is used to replace one or more missing teeth, when functioning teeth are available on both sides of the missing tooth.
The adjacent teeth, called retainers, are covered by the bridge in exactly the same manner as a crown covers a single tooth. The difference is that the bridge connects the crowns to a pontic (fake tooth replacement) in the missing tooth space.
In the case of one missing tooth, a bridge would be three units: one unit for each adjacent retainer tooth, and one for the pontic. Bridges can be made from all of the same materials listed above for crowns.