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== Cementum ==

'''Cementum''' (pronounced: /sɪˈmɛntəm/) 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]].

=== Etymology ===

The term "cementum" is derived from the Latin ''caementum'', meaning "quarry stone", in reference to its hard, stone-like quality.

=== Function ===

Cementum primarily serves to anchor the tooth to the [[alveolar bone]] within the jaw, allowing for stable tooth function. It is also involved in tooth repair and regeneration, and provides a barrier for the underlying [[dentin]].

=== Types ===

There are two types of cementum: acellular (primary) cementum, which is deposited before the tooth erupts, and cellular (secondary) cementum, which forms after eruption.

==== Acellular Cementum ====

Acellular cementum covers about 1/3 to 1/2 of the root and contains no cells. Its primary function is to anchor the tooth to the alveolar bone.

==== Cellular Cementum ====

Cellular cementum covers the apical 1/3 to 1/2 of the root and can contain cementocytes within lacunae. It is less calcified than acellular cementum and its primary function is adaptive, responding to stimuli such as tooth movement or trauma.

=== Related Terms ===

* [[Periodontium]]: The specialized tissues that both surround and support the teeth, maintaining them in the maxillary and mandibular bones.
* [[Alveolar bone]]: The thickened ridge of bone that contains the tooth sockets on bones that hold teeth.
* [[Dentin]]: The dental tissue underneath both the enamel and the cementum of the tooth.
* [[Periodontal ligament]]: The group of specialized connective tissue fibers that essentially attach a tooth to the alveolar bone within which it sits.

[[Category:Dental anatomy]]
[[Category:Human mouth anatomy]]
[[Category:Tooth development]]

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