Cementum Flashcards
formative cell of cementum
cementoblast
formative organ of cementum
dental sac
embryonic origin
ectomesenchyme
terminal ends or periodontal ligament inserted in the cementum/ alveolar bone
sharpey’s fibers
Represent periodic deposition of successive new layer of cementum
Sharpey’s fibers
growth lines, same direction as
dentino-cemental junction
Incremental lines of Salter
Consist of normal assembly of proteoglycans,
glycoproteins and phosphoproteins
Non collagenous Ground Substance
found in periodontal ligament/outside of the cementum that are round, plump cells with basophilic cytoplasm
cementoblast
hemataoxyphilic nucleus with little cytoplasm
resting cementoblasts
reside in cemento matrix or inside the cementum
cementocytes
spaces within the matrix which houses the cell bodies of cementocytes.
lacunae
Elongated, tiny spaces housing the processes -Processes
are directed towards periodontal ligaments to acquire nutrients
since cementum is avascular.
Canaliculi
Morphology of the Cemento-enamel junction
60% overlaps, 30% butt joint, 10% Gap/exposed dentin
Also known as Coronal or Cervical Cementum. It contains neither cementocytes nor no collagen fibrils and it is the product of cementoblasts. May also overlap enamel at DEJ
Acellular Afibrillar Cementum
also called primary cementum or fibrous cementum that has extrinsic fibers (sharpey’s fiber) coming from the periodontal ligament. It has no cells but has fibers that are diagonal or perpendicular to long axis of tooth. A product of cementoblast and seen in cervical portion to midroot portion, directly on the external dentinal surface
Acellular Extrinsic Fiber Cementum
Also known as Secondary cementum. continuously forming due to stimuli and is usually located in near in apical third but may cover the entire cementum. It contains cementocytes and has both sharpey’s fibers and intrinsic bundles of collage fibers. It is a product of cementoblasts and is maintained by cementocytes
Cellular Mixed Fiber Cementum
- contains cementocyte and intrinsic
bundles of collagen fibrils - exclusive products of cementoblast
formed only during reparative
process - No extrinsic fibers
- Filling in of resorption lacunae and
repair of root fractures.
Cellular Intrinsic Fiber Cementum
- 1st layer of cementum formed on dentin
- main purpose: Seals the tubules of dentin
- formed directly on the dentin surface
- Product of epithelial rest of Malassez
- Deposited in the inner layer of the epithelial cells of the root
sheath - Harder consistency
Intermediate Cementum
between the root dentin and
cementum (usually smooth and straight in permanent teeth)
Dentino-Cemental Junction
- longer and slower, capacity to feel the
resoption area, ability to reestablish the original root. - Can fill the entire resorbed area
- Established the normal area
- Slow process
- Entire surface is restored to its actual Reestablish outline of
cementum
Anatomical repair
– only forms cementum on a certain area
of restoration, original root is not established.
- Functional repair- only form cementum on a certain area of
that resorption (not the whole area)
- Fill only the resorption lacuna
- Can’t re-established the original area
- Fast and rapid repair
Functional repair
2 types of repair of cementum
Anatomical and functional repair
fine collagen fibers which lies parallel to the surface of the cementum
intrinsic fibers
Part of the CEJ that is that occurs in 60% of teeth and the most common
Overlapping
Cementum meets the enamel forming a distinct CEJ that occurs in 30% of teeth and is the most second common
Butt-joint
A gap occurs between cementum and enamel that exposes root dentin and occurs in 10% of teeth
Gapped CEJ
An extension of enamel organ that extends apically to the root and the cervical loop
Hertwig’s Epithelial Root Sheath
Acellular, formed slowly and covers coronal 2/3 of the root
Primary cementum
Cellular, found more rapidly and covers apical 2/3 of the root
secondary cementum
2 cells of the cementum
Cementoblasts and cementocytes
