W9 Cementum Flashcards Preview

DOH110 Oral Health sciences 1 > W9 Cementum > Flashcards

Flashcards in W9 Cementum Deck (22)
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1
Q

What is the periodontium?

A

Collecgively refers to cementum, alveolar bone and periodontal ligament

2
Q

What is cementum?

A

Avascular, receives nutrition from PDL space

3
Q

What is the function of cementum?

A

Covers the root surface, seal for the dentinal tubes. Provide attachment for the PFL fibers hold the tooth in it’s socket

4
Q

What is the chemical properties of cementum

A

Inorganic: 45-50% calcium hydroxyapatite
Organic matrix: Collagen fibers, ground substance
Bound water

5
Q

What are the physical properties of Cementum?

A

Yellow, lighter than dentine. Less mineralised than dentine and enamel, hard as bone. Lack lusture, softer than enamel

6
Q

What is the histology classification of cementum?

A
  1. Acellular or Cellular cementum?
  2. Nature of Organic matrix fibers - extrinsic or intrinsic
  3. Combination of 1 and 2
7
Q

Describe acellular cementum?

A

Layer immediately overlying dentine. Deposited by epithelial root cells before root sheet disintergrates. Provides attachment

8
Q

Describe Cellular cementum

A

Thicker layer of cellular cementum. Deposited by cementoblasts, has an adaptive role in response to tooth wear/movement - faster formation. Has Cementocytes

9
Q

What are extrinsic fibres?

A

Sharpeys fibers are a portion of the collagen fibers from the PDL inserted at90 degrees on the outer part of the cementum

10
Q

What are intrinsic fibers

A

Derived from cementoblasts and lay parrallel to root surface at approx right angels to extrinisc fibres

11
Q

What is cemental caries?

A

Root caries that travels into cementum due to gingival recession due to trauma or periodontal disease

12
Q

What is concresence?

A

Union of root structure of more than one two by the cementum

13
Q

What is PDL?

A

Fibrous connective tissue between alveolar process and cementum. Composed of CT, fibers, cells and ground substance

14
Q

What is the function of PDL?

A

Provided attachment of the teeth to the surround alveolar bone by cementum. TO withstand mastication forces.

15
Q

What is the histology composition of PSL?

A

CT fibers: sharpeys fibers

Ground substance 70% water with glycoproteins and proteoglycans, nerves, highly vascular

16
Q

What cells are present in to PDL composition?

A
Fibroblasts: form fibers
Osteoblasts: bone formation
Cementoblasts: form cementum
Endothelial cells
Macrophages and osteoclasts
Epithelial rests 
Undifferentiated mesychymal cells
17
Q

What is the PDL Organisation?

A

Gingival Group - located around necks of the teeth
Transeptal - cementum to cementum
Dentoalveolar - cementum to bone

18
Q

What is the Gingival FIbre group

A
  1. Alveologingival (free)
  2. Dentogingival (attached)
  3. Circumferential fibres
  4. Dento periosteal ligament
19
Q

What is the Transsetal Group?

A

Inserts interproximally from cervial cementum of one tooth to the cervical cementum of neighbouring teeth. Withstands rotational forces

20
Q

What is the Dentoalveolar group?

A
  1. Alveolar crest group - resist tiliting
  2. Horizontal group - mesial, distal buccal lingual tilting + rotational
  3. Oblique group:
  4. Apical group: extrusive + rotational forces
  5. Interradicular
21
Q

What is the chemical composition of alveolar bone?

A

60% inorganic - hydroxy
25% organic
15% water

22
Q

What is the gross anatomy of the alveolar bone?

A

Cortical plate, cribriform plate, cancelous bone