In dental anatomy, the apical foramen, literally translated "small opening of the apex," is the tooth's natural opening, found at the root's very tip—that is, the root apex — whereby an artery, vein, and nerve enter the tooth and commingle with the tooth's internal soft tissue, called pulp. Additionally, the apical foramen is the point where the pulp meets the periodontal tissues, the connective tissues that surround and support the tooth. The foramen is located 0.5mm to 1.5mm from the apex of the tooth. Each tooth has an apical foramen.

Characteristics

The average size of the orifice is 0.3 to 0.4 mm in diameter. There can be two or more foramina separated by a portion of dentin and

cementum Cementum is a specialized calcified substance covering the root of a tooth. The cementum is the part of the periodontium that attaches the teeth to the alveolar bone by anchoring the periodontal ligament. Structure The cells of cementum are ...

or by cementum only. If more than one foramen is present on each root, the largest one is designated as the apical foramen and the rest are considered accessory foramina.

Apical delta

Apical delta refers to the branching pattern of small accessory canals and minor foramina seen at the tip or apex of some

tooth A tooth (: teeth) is a hard, calcified structure found in the jaws (or mouths) of many vertebrates and used to break down food. Some animals, particularly carnivores and omnivores, also use teeth to help with capturing or wounding prey, tea ...

roots. The pattern is said to be reminiscent of a

river delta A river delta is a landform, archetypically triangular, created by the deposition of the sediments that are carried by the waters of a river, where the river merges with a body of slow-moving water or with a body of stagnant water. The creat ...

when sectioned and viewed using a

microscope A microscope () is a laboratory equipment, laboratory instrument used to examine objects that are too small to be seen by the naked eye. Microscopy is the science of investigating small objects and structures using a microscope. Microscopic ...

. Because the anatomy of this area is very small and complex with several portals of entry to the

root canal A root canal is the naturally occurring anatomic space within the root of a tooth. It consists of the pulp chamber (within the coronal part of the tooth), the main canal(s), and more intricate anatomical branches that may connect the root c ...

i.e. more than one apical foramen.Color Atlas and Textbook of Oral Anatomy, Histology, and Embryology by B. K. Berkovitz, G. R. Holland, B. J. Moxham Hardcover, Mosby, (0-8151-0697-1)

Endodontic treatment

It is a point of interest in

endodontics Endodontics () is the Specialty (dentistry), dental specialty concerned with the study and treatment of the dental pulp. Overview Endodontics encompasses the study (practice) of the basic and clinical sciences of normal dental pulp, the etiolo ...

, as it is considered necessary to thoroughly chemomechanically debride the pulp space to remove all necrotic tissue and minimise bacterial load in the pulp space. Ideally, this debridement would terminate exactly at the apical foramen. In reality, determining the exact position of the apical foramen is problematic, requiring

radiography Radiography is an imaging technology, imaging technique using X-rays, gamma rays, or similar ionizing radiation and non-ionizing radiation to view the internal form of an object. Applications of radiography include medical ("diagnostic" radiog ...

and/or use of an

electronic apex locator An electronic apex locator is an electronic device used in endodontics to determine the position of the Apical constriction (dentistry), apical constriction and thus determine the length of the root canal space. The apex of the root has a specific ...

to produce a refined estimate. A tooth may have multiple small accessory canals in the root apex area forming an apical delta which can complicate the endodontic problem. The presence of an apical delta may make successful endodontic treatment less likely. The root tip is removed during apicoectomy to eliminate the apical delta and maximise the chance of successful healing. An apical constriction is often present. In immature teeth the root is not fully formed, leading to an open apex. This is also seen in some pathological teeth.

References

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