What is a dental crown? A dental crown is a tooth-shaped “cap” that is placed over a tooth. The cap restores the tooth’s shape and size, strength, and appearance. The crowns, when cemented into place, cover the visible portion of a tooth. When would a dental crown be needed? A dental crown may be needed to: Protect a weak tooth (for example, from decay) from breaking or to hold together parts of a cracked tooth Restore a broken tooth or a severely worn down tooth Cover and support a tooth with a large filling and not much tooth remaining.