Английская Википедия:Cementicle
Шаблон:Infobox medical condition (new)
A cementicle is a small, spherical or ovoid calcified mass embedded within or attached to the cementum layer on the root surface of a tooth, or lying free within the periodontal ligament.[1][2] They tend to occur in elderly individuals.[3][4]
- Free cementicle – not attached to cementum[5]
- Attached (sessile) cementicle – attached to the cementum surface[5] (also termed exocementosis)[3]
- Embedded (interstitial) cementicle – with advancing age the cementum thickens,[3] and the cementicle may become incorporated into the cementum layer[5]
They may be visible on a radiograph (x-ray).[2] They may appear singly or in groups,[1] and are most commonly found at the tip of the root.[6] Their size is variable,[5] but generally they are small (about 0.2 mm[6] – 0.3 mm in diameter).[5]
Cementicles are usually acellular, and may contain either fibrillar or afibrillar cementum, or a mixture of both.[5] Cementicles are the result of dystrophic calcification,[5] but the reason why this takes place is unclear.[3] 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.[5] Examples of how cementicles are thought to form include:
- Calcification due to degenerative changes in the epithelial cell rests of Malassez[5]
- Calcification of thrombosed (blocked) capillaries in the periodontal ligament[5] (i.e. a phlebolith)[6]
- Microtrauma to Sharpey's fibres[2] causes small spicules of cementum or alveolar bone to splinter into the periodontal membrane[4] Some do not consider these as true cementicles.[5]
References
External links
Шаблон:Medical resources Шаблон:Oral pathology
