Crowns
Crowns are a type of dental restoration which, when cemented into place, fully cup over the portion of a tooth which lies at and above the gum line. In comparison, fillings are dental restorations that are used to fill in or cover over just a portion of a tooth. Since dental crowns encase the entire visible aspect of a tooth, a dental crown in effect becomes the tooth's new outer surface.
Crowns can be made out of porcelain (or some other ceramic material), gold (or metal alloys), or a combination of both. Dental crowns are often referred to as "dental caps" or "tooth caps".