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's apex—whereby an artery, vein, and nerve enter the tooth and commingle with the tooth's internal soft tissue, called

pulp Pulp may refer to: * Pulp (fruit), the inner flesh of fruit Engineering * Dissolving pulp, highly purified cellulose used in fibre and film manufacture * Pulp (paper), the fibrous material used to make paper * Molded pulp, a packaging material ...

. Additionally, the apical foramen is the point where the pulp meets the

periodontal Periodontology or periodontics (from Ancient Greek , – 'around'; and , – 'tooth', genitive , ) is the specialty of dentistry that studies supporting structures of teeth, as well as diseases and conditions that affect them. The supporting ...

tissues, the connective tissues that surround and support the tooth.

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.Illustrated Dental Embryology, Histology, a ...

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, tear ...

roots. The pattern is said to be reminiscent of a

river delta A river delta is a landform shaped like a triangle, created by deposition (geology), deposition of sediment that is carried by a river and enters slower-moving or stagnant water. This occurs where a river enters an ocean, sea, estuary, lake, res ...

when sectioned and viewed using a

microscope A microscope () is a 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 means being invisibl ...

. 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 ...

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 (from the Greek roots ''endo-'' "inside" and ''odont-'' "tooth") is the dental specialty concerned with the study and treatment of the dental pulp. Overview Endodontics encompasses the study (practice) of the basic and clinical ...

, as it is considered necessary to thoroughly chemomechanically

debride Debridement is the medical removal of dead, damaged, or infected tissue to improve the healing potential of the remaining healthy tissue. Removal may be surgical, mechanical, chemical, autolytic (self-digestion), and by maggot therapy. In po ...

the pulp space to remove all

necrotic tissue Necrosis () is a form of cell injury which results in the premature death of cells in living tissue by autolysis. Necrosis is caused by factors external to the cell or tissue, such as infection, or trauma which result in the unregulated diges ...

and minimise

bacterial load Bacteria (; singular: bacterium) are ubiquitous, mostly free-living organisms often consisting of one biological cell. They constitute a large domain of prokaryotic microorganisms. Typically a few micrometres in length, bacteria were among ...

in the

pulp space Pulp may refer to: * Pulp (fruit), the inner flesh of fruit Engineering * Dissolving pulp, highly purified cellulose used in fibre and film manufacture * Pulp (paper), the fibrous material used to make paper * Molded pulp, a packaging material ...

. 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 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 radiography ("diagnostic" and "therapeu ...

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 and thus determine the length of the root canal space. The apex of the root has a specific resistance to electrical current ...

to produce a refined estimate. A tooth may have multiple small accessory canals in the root apex area forming an

apical delta 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's apex—whereby an artery, vein, and nerve enter the tooth and commingle w ...

which can complicate the endodontic problem. The presence of an apical delta may make successful

endodontic Endodontics (from the Greek roots ''endo-'' "inside" and ''odont-'' "tooth") is the dental specialty concerned with the study and treatment of the dental pulp. Overview Endodontics encompasses the study (practice) of the basic and clinical ...

treatment less likely. The root tip is removed during

apicoectomy A root end surgery, also known as apicoectomy ('' apico-'' + '' -ectomy''), apicectomy ('' apic-'' + '' -ectomy''), retrograde root canal treatment (''c.f.'' orthograde root canal treatment) or root-end filling, is an endodontic surgical procedu ...

to eliminate the apical delta and maximise the chance of successful healing. An

apical constriction Apical constriction is the process in which contraction of the apical side of a cell causes the cell to take on a wedged shape. Generally, this shape change is coordinated across many cells of an epithelial layer, generating forces that can bend o ...

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

Parts of tooth {{anatomy-stub