(6) Cementum Flashcards
Is precemnetum calcified or uncalcified?
Uncalcified
Is cementum more or less hard than dentin and enamel?
Softer than
Is cementum more permeable than dentin?
Yes
More permeable
What percent of cementum is organic, inorganic and water?
Inorganic - 65%
Organic - 23%
Water - 12%
What is the structure of hydroxyapatite in cementum?
Thin plate like apatite crystals
What are the non-collage ours components of cementum, which are similar to bone?
Sialoprotein and osteopntin
What are the 2 types of cementum?
Cellular and cellular
What are the 3 types of cementum fibres based of their origin?
Extrinsic fibre cementum
Intrinsic fibre cementum
Mixed fibre cementum
What is extrinsic fibre cementum?
Only has fibres form outside cementum
Sharpeys fibres from outside the cementum
What is intrinsic cementum?
No periodontal ligament fibres inserted into it
What is the common type of cementum fibre?
Mixed fibre cementum
What is mixed fibre cementum?
Collagen fibres that are deposited by cementoblasts (intrinsic fibres)
Extrinsic fibres form the periodontal ligament
What produces intricacies fibres?
Collagen from cementoblasts
How would you classify cementum which has fibres from the periodontal ligament and has no cells present?
Acellular extrinsic cementum
How would you classify cementum which has cells present and fibres from the cementoblasts?
Cellular intrinsic cementum
What are the 2 categories to classify cementum?
- Acellular/ cellular
- Intrinsic fibres/ extrinsic fibres/ mixed fibres
Can you get afibrillar cementum?
Yes
Very rare
Where is cementum mainly located?
In the picas area and inter-redicular areas overlying acellular cementum
Where is acellular cementum normallly found?
Cervically
What is primary cementum?
Acellular
What is secondary cementum?
Cellular
A = ACELLULAR
B = cellular
C = cementocyte in howships lacunae
D = cementoblasts
E = pre-cementum
F = cementoblasts lining pre-cementum
G = periodontal ligament
What is the dark layer between the cellular and acellular cementum?
Afibrillar cementum
What is the hyaline layer
hyaline layer of Hopewell-Smith is the most peripheral layer of initially unmineralized dentin that forms immediately subjacent to the cementodentinal junction (CDJ).
What direcention do the canaliculi orientate?
Towards periodontal ligament (vascular)