3. Physical Characteristics
1-Color
Light yellow
Lighter in color than dentin
2- Thickness
Acellular cementum (20-50 m)
Cellular cementum (150-200 m)
3- Permeability
Permeable from dentin and PDL sides.
Cellular C is more permeable than acellular C.

4. Chemical Composition
45-50 % Inorganic 50-55% Organic
substances substances
Collagen
Hydroxyapatite
crystals protein
Polysaccharides
Trace elements
Cementum contains the greatest amount of
fluoride in all mineralized tissues

5. Cementum Structure
C D D
C
Acellular cementum Cellular cementum

6. Cementocytes
Epithelial
rest of
Malassez
Cementoid
layer
Acellular cementum Cellular cementum

7. Acellular Cementum
Thickness is 20-50 µ.
It is clear and structureless
Covers the coronal half of
the root.
Incremental lines of Salter
are parallel to the surface.
Sharpey’s fibers space can
be seen in it .

8. Alternating layers of
a cellular and
cellular cementum
could be seen.

9. Cellular Cementum
Lacunae of cementocytes
PDL side
Cementocytes
Dentin side

10. Incremental lines of Salter
Cementocytes

11. Cementocyte And Osteocyte
Dentin side
Osteocyte
Lacuna
Canaliculi
PDL side

12. Cementocyte And Osteocyte
Dentin side
Osteocyte
Lacuna
Canaliculi
Periodontal
ligament side

13. Cellular Cementum
Viable
Dentin side superficial
cementocytes
Degenerated
deep layer’s
cementocytes
PDL side

14. Incremental Lines Of Salter
In acellular C In cellular C
They are hypermineralized area with less
collagen fibers and more ground substance

15. Cemento Dentinal Junction
C
D
Smooth in permanent teeth Scalloped in deciduous teeth

16. Cemento Enamel Junction
10% cementum and enamel
don’t meet because of 60%
30% cementum
cementum
meets the enamel delayed separation of epith
overlaps E
in a sharp line root sheath of Hertwig (area
of dentin not covered by C). (afibrillar
cementum)

17. Afibrillar Cementum
Before tooth eruption, The connective tissue of
the enamel at the the dental sac lay down
cervical area lose its cementum on the
REE covering. exposed enamel

18. Types Of Cementum
• 1- Acellular cementum.
• 2- Cellular cementum.
• 3- Afibirllar cementum.

19. Functions Of Cementum
1- Acts as a medium for
attachment of collagen
fibers of PDL
(Sharpey’s fibers).
2- The continuous Cementoid T
formation of cementum
keeps the attachment
apparatus intact.
Cementoblast

20. 3- Cementum
deposition epically
compensate for the
attrition.
4- It is a major
reparative tissue
( as in case of fracture
or resorption of
root)

21. Cementogenesis
• 1- Matrix formation • 2- Mineralization
and Maturation
Collagen Ground Hydroxy apatite
fiber type I substance crystals

22. 1- Matrix formation
• Cementum is
formed during root Cementoblasts
formation
D
HER
Future C E J Epith. Diaph.

23. Cementoblast is a protein forming and secreting cell.
Collagen fibers +
ground substance.
D
Large nucleus with dispersed
chromatin threads.
Cementoblast
RER
Golgi apparatus
Mitochondria
Secretory granules
Alkaline phosphatase

24. Maturation occur layer
by layer for the
collagen fibers
Cementum
Cementoblasts
Cementoid layer

25. Age Changes Of The Cementum
1- Hypercementosis.
Localised
D
D
May affect one tooth or all teeth Hypercementosis

26. Types Of Hypercementosis
Hypercementosis Hypercementosis
hypertrophy hyperplasia
Increase number of Decrease number of
Sharpey’s fibers Sharpey’s fibers

27. 2- Permeability
From
From dentin periodontal
side side, but remain
remains at at the
apical area superficial
ONLY recently formed
layers