A dental crown is a tooth-shaped "cap" that is placed over a tooth-- to cover the tooth to restore its shape and size, strength, and improve its appearance.
Crowns, when cemented into place, fully encase the entire visible portion of a tooth that lies at and above the gum line.
Dental veneers (sometimes called porcelain veneers or dental porcelain laminates) are wafer-thin, custom-made shells of tooth-colored materials designed to cover the front surface of teeth to improve your appearance. These shells are bonded to the front of the teeth changing their color, shape, size, or length.
Dental bridges bridge the gap created by one or more missing teeth.
A bridge is made up of two or more crowns for the teeth on either side of the gap -- these two or more anchoring teeth are called abutment teeth -- and a false tooth/teeth in between. These false teeth are called pontics and can be made from gold, alloys, porcelain, or a combination of these materials. Dental bridges are supported by natural teeth or implants.