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.