Definition and Types of Cementicles - Cementicle is a calcified mass in or attached to the cementum layer on a tooth's root surface. - There are 3 types: free cementicle, attached (sessile) cementicle, and embedded (interstitial) cementicle. - Free cementicles are not attached to cementum. - Attached cementicles are attached to the cementum surface (also known as exocementosis). - Embedded cementicles are incorporated into the cementum layer with age.

Appearance and Location of Cementicles - Cementicles may be visible on a radiograph (x-ray). - They can appear singly or in groups. - Most commonly found at the tip of the root. - Size varies, but generally small (about 0.2 mm – 0.3 mm in diameter). - Cementicles are usually acellular.

Composition of Cementicles - Cementicles may contain fibrillar or afibrillar cementum, or a mixture of both. - They result from dystrophic calcification. - The reason for their formation is unclear. - Calcification may occur around a nidus, a precipitating center. - Further deposition of calcium salts leads to their enlargement.

Formation of Cementicles - Examples of how cementicles form include calcification of epithelial cell rests of Malassez. - Calcification of thrombosed (blocked) capillaries in the periodontal ligament (phlebolith). - Microtrauma to Sharpeys fibres causes small spicules of cementum or alveolar bone to splinter into the periodontal membrane. - Some do not consider these as true cementicles. - The formation process is still not fully understood.

References - Chiego Jr. DJ, Essentials of Oral Histology and Embryology: A Clinical Approach. - Bath-Balogh M, Fehrenbach MJ, Illustrated Dental Embryology, Histology, and Anatomy. - Kumar GS, Orbans Oral Histology & Embryology. - Mosby, Mosbys Dental Dictionary. - Ghom A, Mhaske S, Textbook of Oral Pathology.