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The Apex of the Tooth

The apex of the tooth, or the apices of the teeth, in the plural, is the tip of the tooth root. It performs vital functions in the mouth by letting in and out nerve tissues, lymphatic vessels, and blood vessels. If infected, the apex can be removed via a surgical procedure called apicectomy. 

The Apex of the Tooth – Related Terminology

Terminal End

Another name for the apex of the tooth. It is the extreme end of the tooth root.

Apical Foramen

The opening of the apex of the tooth. Through this opening, blood vessels and nerve tissues reach the pulp to keep the tooth alive. It is sometimes used synonymously with the apex.

Apical foramen remains wide open during the formation period of the tooth.

It is the spot where the pulp chamber of the tooth ends.


Also called apicectomy. An example of a periradicular surgery. In case of an infection, this surgical procedure is used to remove the apex of the tooth. The cavity is filled with a filling material.

According to Dental Research and Management, apicoectomy as a treatment procedure is recommended when a root canal treatment fails and a second root canal treatment is not advised.

Root-end Filling

Another name for apicectomy.

According to research, mineral trioxide aggregate has the best success rate among all root-end filling materials. It is a calcium silicate-based material.

Calcium hydroxide is another commonly used root-end filling material.

Research has also shown that interim restorative material (IRM) has a highly positive response rate when filling a root-end. IRM is an oxide-zinc eugenol cement.

Apical Periodontitis

It is an acute inflammatory condition around the apex of a tooth root. Apical means something that is related to the apex. You may have this condition if you have serious tooth decay, dental trauma, bacterial infection in the pulp. An extreme form of this condition is pulpal necrosis.

Periapical Abscess

Periapical abscess is the infection of the periapical tissue. In turn, periapical tissues are the tissues that surround the apex of a tooth.

The infection occurs when bacteria enter the dental pulp chamber and attack the pulp. The result is serious inflammation and tooth loss or bone loss.

You may have periapical abscess if your immune system is not strong enough to prevent bacterial growth.

How many apices does a tooth have?

A tooth may have more than one apex. It depends on the type of the tooth. Incisors, canines and premolars have one root. Therefore, they have one apex. On the other hand, molars have two to three apices because they have two to three roots.

Wisdom teeth may have one to three roots. Therefore, the number of apices they have varies.

When does the apex of a tooth close?

The apex of the tooth closes three years after the eruption of the tooth. By that time the tooth receives its fully developed shape.

If a tooth has serious decay and requires a root canal treatment, the apex may be closed through a surgery. That surgery is called Apexification. It is the treatment of choice for young patients whose permanent teeth have not fully developed.

Apicoectomy is not the best choice in such a case because the removal of the apex enables a disproportionate crown root ratio.

What causes an open tooth apex?

Many factors may prevent the apex of a tooth root from closing after the tooth has achieved maturity. An authoritative dental research on this subject has mentioned the following factors in particular:

  • Cavities
  • Dental trauma
  • Pulp necrosis
  • Incomplete root development
  • Root canal infection

What materials are used to close the apex of a tooth?

Calcium hydroxide has been commonly used since 1964 as the filling material for closing the apex of a tooth. Over the decades, many dentists have mixed it with different substances, such as:

  • Camphorated mono chlorophenol, to reduce bacteria in the root canals
  • Saline solution
  • Water
  • Anesthetic solutions
  • Chlorhexidene, to reduce inflammation of the gum and gum disease
  • Cresatin, to prevent bacterial and fungal infections.

What is an apexum?

The apexum is a dental treatment technique which shows much better results over conventional root canal therapy in the treatment of chronically inflamed apical or periapical tissues.

The technique uses the root canal access to insert a device to remove or partially remove the infected tissues from the root of the teeth.

The apexum helps inflammation of the periapical tissue faster than the root canal therapy.

However, the apexum does not remove the cyst lining. That may trigger the inflammation at a later date.


Yen-Ching Chao, et al. (2022). Effectiveness of different root-end filling materials in modern surgical endodontic treatment: A systematic review and network meta-analysis. Journal of Dental Sciences.

Murugesan Gawthaman, et al. (2013). Apexification with calcium hydroxide and mineral trioxide aggregate: Report of two cases. Journal of Pharmacy & Bioallied Sciences.

Lino Lucio Locurcio, et al. (2017). A case of periradicular surgery: apicoectomy and obturation of the apex, a bold act. Stomatological Disease and Science.

Robert Smyth, et al. (2017). Management of the open apex in endodontics. Scottish Dental Magazine.

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