Formation and Function of the Cementoenamel Junction
- The cementoenamel junction (CEJ) is formed at the union of cementum and enamel.
- The CEJ serves as the attachment site for the gingiva.
- Active recession of the gingiva exposes the CEJ, indicating an unhealthy condition.
- Tooth resorption, which occurs in 5 to 10 percent of the population, often takes place at the CEJ.
- The CEJ is used as a landmark for measuring probing pocket depth (PPD) and clinical attachment level (CAL).
Types of Cementoenamel Junction
- Coronal cementum overlaps the enamel at the CEJ.
- Abutment occurs when the cementum and enamel meet without overlap.
- A gap between the cementum and enamel exposes the dentin.
Curvature of the Cementoenamel Junction
- The shape and location of the CEJ vary between teeth.
- Anterior teeth have a greater curvature at the CEJ compared to posterior teeth.
- On anterior teeth, the distal aspect of the CEJ is usually one mm lower than the mesial aspect.
- Posterior teeth have flatter CEJ curvatures on interproximal surfaces.
Teeth Resorption at the Cementoenamel Junction
- Root resorption often starts at the CEJ.
- Internal resorption includes root canal replacement resorption and internal inflammatory resorption.
- External resorption can be categorised into external surface resorption, external inflammatory root resorption, replacement resorption, and ankylosis.
- External inflammatory root resorption can further be classified into cervical resorption with or without a vital pulp and external apical root resorption.
References
- Vandana KL and Haneet RK provide insights on the cementoenamel junction in their study published in the Journal of Indian Society of Periodontology.
- Clemente CD's book, 'Anatomy, a regional atlas of the human body,' discusses the cementoenamel junction.
- Carranza FA, Bernard GW, and Newman MG's books provide information on the tooth-supporting structures and clinical periodontology.
- Scheid RC's book, 'Woelfels Dental Anatomy,' covers dental anatomy.
- Metwally S and Stachewicz U's study in Micron analyzes teeth resorption at the cement-enamel junction.
Cementoenamel junction (CEJ) is defined as the area of the union of cementum and enamel at the cervical region of the tooth. It is a slightly visible anatomical border identified on a tooth. It is the location where the enamel, which covers the anatomical crown of a tooth, and the cementum, which covers the anatomical root of a tooth, meet. Informally it is known as the neck of the tooth. 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.
| Cementoenamel junction | |
|---|---|
 Labeled molar | |
 The CEJ is the more or less horizontal demarcation line that distinguishes the crown (A) of the tooth from root (B) of the tooth. | |
| Identifiers | |
| MeSH | D019237 |
| Anatomical terminology | |
Active recession of the gingiva reveals the cementoenamel junction in the mouth and is usually a sign of an unhealthy condition. The loss of attachment is considered a more reliable indicator of periodontal disease. The CEJ is the site of major tooth resorption. A significant proportion of tooth loss is caused by tooth resorption, which occurs in 5 to 10 percent of the population. The clinical location of CEJ which is a static landmark, serves as a crucial anatomical site for the measurement of probing pocket depth (PPD) and clinical attachment level (CAL). The CEJ varies between subjects, but also between teeth from the same person.
There exists a normal variation in the relationship of the cementum and the enamel at the cementoenamel junction. In about 60–65% of teeth, the cementum overlaps the enamel at the CEJ, while in about 30% of teeth, the cementum and enamel abut each other with no overlap. In only 5–10% of teeth, there is a space between the enamel and the cementum at which the underlying dentin is exposed.
