9 Periodontium Flashcards
T/F: Primary cementum contains cells.
False. As primary cementum is secreted, the cementoblasts retreat toward the location of the future PDL. They are out of the way when mineralization of the cementum occurs.
T/F: Primary cementum is deposited as the tooth is erupting into the mouth.
True. Primary cementum is the first-deposited. It is initiated soon after that root dentin begins to be laid down and occurs simultaneously with the elongation of the root and eruption into the oral cavity (ie simultaneous with the pre-functional stage of eruption).
Identify location where primary cementum is most abundant.

Top: No, this is enamel.
Middle: Yes, primary cementum is more abundant in the cervical part of the tooth, reflecting the fact that it’s laid down first, and that cementogenesis proceeds from the CEJ to the root apex.
Bottom: No, this is the lcoation where secondary cementum is most abundant. Cementogenesis proceeds from the CEJ to the root apex, and primary cementum is secreted before secondary cementum.
Explain the mechanism responsible for the development of a secure attachment between dentin and cementum.
The initial organic matrix of cementum is composed of collagen fibers which intermingle with the adjacent unmineralized dentin amtrix prior to the mineralization of both these tissues.
Identify tissues.

L: acellular cementum
R: dentin/root
Identify tissues.

L: aceullar cementum
M: Tomes’ granular layer = hypomineralized regions in mantle dentin of the root
R: dentin, tubules organized at right angles to CEJ
Identify tissues.

L: Cellular cementum, dark areas are trapped cells called cementocytes, much thicker than previous acellular cementum
R: dentin
Identify.

Sharpey’s fibers.
Identify. Name an analogous structure in the dental pulp.

Cementicle. Pulp stones
Identify.

Alveolar crest.
Identify.

Red: horizontal
Blue: alveolar crest
Identify.

Both are oblique.
Identify.

Interradicular
Which represents cancellous/trabecular bone and which represents the cortical plate?

Orange: cancellous/trabecular
Blue: cortical platecomprised of lamellar and compact haversion system bone
Identify alveolar crest bundles.

Top: alveolar crest fiber bundles
Bottom: oblique fiber bundle
Identify.

- gingiva 2. PDL 3. alveolar bone 4. cementum
Identify

Both are periodontal ligament.
Identify.

- Periodontal ligament 2. Lamina dura 3. Cementum
Identify.

- Periodontal ligament (radiolucent)
- Lamina dura (opaque)
Identify.

- cementum
- periodtondal ligament
- alveolar bone
Identify.

- cementum
- periodontal ligament
- lamina dura
- trabecular bone
- bone marrow
Identify.

- cementum
- principal fiber bundles of PDL
- interstial space (site of larger vessels and nerves)
- alveolar bone
Identify.

- alveolar crest
- horizontal
- oblque
- apical
- interradicular
Most numerous cell type of PDL.

Fibroblast.















































