Difference between
acellular and cellular cementum
acellular and cellular cementum
|
|
Acellular
cementum |
Cellular
cementum |
|
Commonly seen in
|
Cervical and middle
third of root |
Apical third of root
|
|
Position of cells
|
No cells
|
Lacunae and canaliculi
containing cementocytes and their processes |
|
Border with dentin
|
Not clearly
demarcated |
Clearly demarcated
|
|
Rate of development
|
Relatively slow
|
Relatively fast
|
|
Incremental lines
|
Relatively close
together |
Relatively wide
apart |
|
Precementum layer
|
Virtually absent
|
Present
|
Difference between
alveolar bone, cementum, dentin and enamel
alveolar bone, cementum, dentin and enamel
|
|
Alveolar bone
|
Cementum
|
Dentin
|
Enamel
|
|
Derived from
|
Mesoderm
|
Ectomesenchyme
|
Ectomesenchyme
|
Ectoderm
|
|
Cell of origin
|
Osteoblast
|
Cementoblast
|
Odontoblast
|
Ameloblast
|
|
Cells in mature tissue
|
Osteocytes
|
Cemetocytes (absent in acellular cementum)
|
Odontoblasts
|
Does not persist
|
|
Degrading cells
|
Osteoclasts
|
Cementoclasts / odontoclasts
|
Odontoclast
|
Odontoclast
|
|
Matrix vesicle formation
|
Observed
|
Observed
|
Observed
|
Not seen
|
|
Apatite content (in %)
|
50 to 60
|
45 -50
|
70
|
96
|
|
Primary organic content
|
Collagen
|
Collagen
|
Collagen
|
Enamel proteins
|
|
Remodeling
|
High rate
|
No remodeling
|
No remodeling
|
No remodeling
|
|
Repair
|
By new bone
|
By new cementum
|
By tertiary dentin
|
No repair except remineralization in surface
|
|
Incremental lines
|
Resting and reversal lines
|
Slater
|
Von Ebner, Owen, neonatal line
|
Retzius, neonatal line
|
|
Nerve innervation
|
Yes
|
Nil
|
Yes – only pain fibers
|
Nil
|
|
Vascularity
|
Yes
|
No vascular channels
|
No vascular channels
|
No vascular channels
|