Cementoenamel junction

Overview
The cementoenamel junction, frequently abbreviated as the CEJ, is an anatomical landmark identified on a tooth. It is the location where the enamel, which covers the crown of a tooth, and the cementum, which covers the root of a tooth, meet. The border created by these two dental tissues has much significance as it is usually the location where the gingiva attaches to a healthy tooth by fibers called the gingival fibers.

Active recession of the gingiva reveals the cementoenamel junction in the mouth and is usually a sign of an unhealthy condition.