A crown, also appertained to as a cap, is a dental restoration that covers the entire tooth, replacing its external enamel with a new material.
Crowns can be fabricated out of numerous different materials including plastic, acrylic, metal, porcelain and zirconia or a combination of these.
A tooth needs a crown when it no longer is strong enough to repel normal chewing function on its own.
A bridge is a fixed partial denture which is fused to the teeth, it replaces some (not all) of the teeth, and it uses a artificial tooth or teeth in the place of missing teeth.
A bridge is used to replace one or more missing teeth, when the functional teeth are available on both sides of the missing tooth.
A bridge is a quick way to replace 1 or 2 missing teeth without any surgery.