3. Dr. M. Saad Shaikh
q Furnishes a medium for the
attachment of collagen fibers that
bind the tooth to surrounding
structures.
q Makes functional adaptation of
the teeth possible.
q Unlike bone, human cementum is
avascular.
4. Physical Characteristics
q Hardness: Cementum < Dentine
q Light yellow in color.
q Distinguished from enamel by its lack of luster and its darker
hue.
q Semi-permeable to a variety of materials.
Dr. M. Saad Shaikh
7. qPrincipal component is HAp, the crystals being thin and plate-like
and similar to those in bone.
qOther trace elements can be found within the HAp and
substitutions are particularly found towards the external surface
of the cementum.
Dr. M. Saad Shaikh
8. qFluoride is the most common ionic substitution, and is found in
higher levels in acellular cementum than cellular cementum.
qCalcification is possibly initiated by the root dentine and
continues on and around the collagen fibers found in
cementum.
Dr. M. Saad Shaikh
9. Dr. M. Saad Shaikh
Organic Matrix
Collagen (90%)
Non-Collagenous
Proteins (10%)
10. qThe organic matrix is collagen, with non-collagenous proteins
being thought to be the same as in alveolar bone.
qCollagen accounts 90% of the organic matrix, majority being type
I collagen with some trace amounts of type III, mainly at the
insertion points of the extrinsic Sharpey fibres.
qTrace amounts of other types of collagen have also been
reported.
Dr. M. Saad Shaikh
11. qThe non-collagenousmatrix accounts 10% of the organic matrix.
qImportant non-collagenous molecules found in cementum are
the proteoglycans decorin and biglycan, bone sialoprotein (BSP),
osteonectin,osteopontin,tenascin and fibronectin.
qThere may be present a cementum-specific glycoprotein called
Cementum Attachment Protein (CAP) that promotes the
attachment of mesenchymal cells to the extracellular matrix.
Dr. M. Saad Shaikh
13. Cementoblasts
q Following Hertwig’s sheath fragmentation, undifferentiated
mesenchymal cells from adjacent connective tissue
differentiate into cementoblasts.
q Synthesize collagen & protein polysaccharides which makes
up the cementum organic matrix.
q Have numerous mitochondria, a well-formed golgi apparatus,
& large amounts of granular ER.
Dr. M. Saad Shaikh
15. Cementocytes
Dr. M. Saad Shaikh
qRepresents entrapped cementoblasts.
qRelativelyinactive.
qSpaces that cementocytes occupy in cellular cementum à
Lacunae.
qChannels that their processes extend along à Canaliculi.
qCytoplasmic/nuclear ratio is low and sparse distribution of
organelles responsible for protein synthesis.
16. Dr. M. Saad Shaikh
Cementocytes
Cell Processes
Cementoid
18. Cementoid Tissue
q The uncalcified matrix is called cementoid.
q Mineralizationof cementoidis a highlyordered event.
q Fibers are embedded in the cementum & serve to attach the
tooth to surrounding bone. Their embedded portions are
known as Sharpey’s fibers.
Dr. M. Saad Shaikh
21. Dr. M. Saad Shaikh
Acellular Extrinsic Fiber
Cementum
Cellular Intrinsic Fiber
Cementum
Cellular Mixed Fiber
Cementum
Acellular Afibrillar
Cementum
22. Dr. M. Saad Shaikh
Acellular Extrinsic Fiber
Cementum
23. qPrimary Acellular Cementum: First formed cementum and
layers attain a thickness of approximately15 μm.
qLocation: cervical 2/3rd of the root & comprises nearly all of
the cementum in some teeth.
qCollagen:derived as sharpey’s fibers from the PDL.
qCells: no Cementocytes.
qRate: Formed Slowly.
qRoot Surface: Smooth.
qFunction:Anchorage.
Dr. M. Saad Shaikh
25. Dr. M. Saad Shaikh
Cellular Intrinsic Fiber
Cementum
26. Dr. M. Saad Shaikh
qSecondary Cellular Cementum
qLocation:Apical 3rd and inter-radicular region of molars.
qCollagen:Intrinsic fibers running parallel to the root surface.
qCells: Cementocytes present.
qRate: Formed more rapidly.
qRoot Surface: Has a cementoidseam on its outer surface.
qFunction: Absence of sharpey’s fibers means that CIFC has no
role in attachment and therefore its main function is Adaptation.
28. Dr. M. Saad Shaikh
Cellular Mixed Fiber
Cementum
29. Dr. M. Saad Shaikh
qAcellular extrinsic and cellular intrinsic fiber cementum may
be present in alternating layers.
qFound at root apex and in the furcation areas of multi-
rooted teeth.
qMain function à Adaptation
30. Dr. M. Saad Shaikh
Acellular Afibrillar
Cementum
31. Dr. M. Saad Shaikh
qContains no collagen fibers.
qSparsely distributed as a thin, acellular layer that covers
cervical enamel or intervenes between fibrillar cementum and
dentine.
32. Type Origin of fibers Location Function
Acellular (Primary) Extrinsic From cervical
margin to the apical
3rd
Anchorage
Cellular (Secondary) Intrinsic Middle to apical 3rd
and furcations
Adaptation
Mixed (alternating
layers of cellular
and acellular
cementum)
Intrinsic and
Extrinsic
Apical portion and
furcations
Adaptation
Acellular afibrillar ---- Spurs and patches
over enamel and
dentine
No known function
Dr. M. Saad Shaikh
35. Incremental Lines
qCementum is deposited rhythmically, resulting in unevenly
spaced incremental lines (of Salter).
qIn acellular cementum, incremental lines tends to be closer,
thin and even.
qIn the more rapidly formed cellular cementum, the line are
further apart, thicker and more irregular.
Dr. M. Saad Shaikh
37. Cemento-Dentinal Junction
q Smooth in permanent teeth.
q Scalloped in deciduous teeth.
q Dentin is separated from
cementum by a layer termed
intermediate cementum.
q Predominantly seen in apical
2/3rd of molars & premolars.
Dr. M. Saad Shaikh
Dentine
Intermediate
Cementum
Cellular
Cementum
43. q Cementum is more resistant to resorption than bone & for this
reason orthodontictooth movement is made possible.
q Because bone is richly vascularized, whereas cementum is
avascular.
q Cementum resorption can occur after trauma or excessive
occlusal forces.
q Resorption is carried out by multi-nucleated odontoclasts and
may continue intothe root dentine.
Dr. M. Saad Shaikh
44. qMay be filled by deposition of mineralized tissue from a layer of
cementoblast-like cells.
qA reversal line may be seen separating the repair tissue from
the normal underlying dental tissues.
qIn case of slow repair, tissue may be acellular.
qHowever, where the repair tissue is formed rapidly it may be
cellular.
Dr. M. Saad Shaikh
46. Hypercementosis
q Is an abnormal thickeningof cementum.
q May be diffuse or circumscribed.
q May affect all the teeth, be confined to a single tooth, or
even affect only part of one tooth.
Dr. M. Saad Shaikh
