cementoenamel

Cementoenamel, specifically the cementoenamel junction (CEJ), is the anatomical boundary where the enamel covering the crown meets the cementum that covers the root of a tooth. Located near the cervical area of a tooth, the CEJ serves as a key reference point in dental examinations, periodontal assessment, and radiographic analysis.

The CEJ is formed during tooth development as the crown and root tissues mature. Enamel is produced by ameloblasts on the crown, while cementum is laid down on the root by cementoblasts. The junction is the point where these two tissues meet. Patterns at the CEJ vary among teeth and individuals; common variations include enamel overlapping cementum, cementum overlapping enamel, or a direct edge-to-edge contact with little or no overlap, which may leave a small exposed area of dentin.

Clinically, the CEJ is important as a landmark for evaluating periodontal health, attachment loss, and bone levels. Exposed cementum or dentin due to gingival recession or abrasion can be sensitive and prone to root caries and wear. The CEJ also informs procedures such as scaling and root planing, crown lengthening, and other periodontal or restorative treatments, where precise measurement and localization of the boundary influence planning and outcomes.