What is A Dental Crown. Dental crown is very common in dental care services provided by a dentist. A dental crown is a tooth shaped “cap” (some people refer to crowns as caps) that is placed over a tooth. The dental crown covers the tooth to restore the tooth shape and size, strength, and or to improve it’s appearance. The crown, when cemented into place, will fully encases the entire visible portion of a tooth that lies at and above the gum line.