A cementicle is a small, spherical or ovoid
calcified
Calcification is the accumulation of calcium salts in a body tissue. It normally occurs in the formation of bone, but calcium can be deposited abnormally in soft tissue,Miller, J. D. Cardiovascular calcification: Orbicular origins. ''Nature Ma ...
mass embedded within or attached to the
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, ...
layer on the root surface of a tooth, or lying free within the
periodontal ligament.
They tend to occur in elderly individuals.
There are 3 types:
* Free cementicle – not attached to cementum
* Attached (sessile) cementicle – attached to the cementum surface
(also termed exocementosis)
* Embedded (interstitial) cementicle – with advancing age the cementum thickens,
and the cementicle may become incorporated into the cementum layer
They may be visible on a radiograph (x-ray).
They may appear singly or in groups,
and are most commonly found at the tip of the root.
Their size is variable,
but generally they are small (about 0.2 mm
– 0.3 mm in diameter).
Cementicles are usually acellular, and may contain either fibrillar or afibrillar cementum, or a mixture of both.
Cementicles are the result of dystrophic calcification,
but the reason why this takes place is unclear.
Cementicles are thought to form when calcification occurs around a nidus, a precipitating center. Around this nidus they slowly enlarge by further deposition of calcium salts.
Examples of how cementicles are thought to form include:
* Calcification due to degenerative changes in the
epithelial cell rests of Malassez
In dentistry, the epithelial cell rests of Malassez (ERM) or epithelial rests of Malassez (''pax epithelialis pediodontii'') are part of the periodontal ligament cells around a tooth. They are discrete clusters of residual cells from Hertwig's ep ...
* Calcification of
thrombosed (blocked) capillaries in the periodontal ligament
(i.e. a
phlebolith
A phlebolith is a small local, usually rounded, calcification within a vein. These are very common in the veins of the lower part of the pelvis, and they are generally of no clinical importance. When located in the pelvis they are sometimes difficu ...
)
* Microtrauma to
Sharpey's fibres causes small spicules of cementum or alveolar bone to splinter into the periodontal membrane
Some do not consider these as true cementicles.
References
External links
{{oral pathology
Periodontal disorders