Periodontium 3 Flashcards
The PDL is __________ tissue.
Soft connective tissue
What are the major component of the PDL?
- highly organized collagen fibers
What is the thickness of the PDL?
0.2-0.4mm *Gets thinner with age
What are the cells of the PDL?
- Fibroblasts (Most common)
- Cementoblasts
- Osteoblasts
- Osteoclasts
- Epithelial cells
- Epithelial rest of Mallasez
- stem cells
______ cells are responsible for both secreting and degrading collagen.
fibroblasts (they are very active cells in the PDL)
What are the cell-to-cell contacts of the PDL fibroblasts?
- Desmosomes
- Gap Junctions
- Fibroblasts also exhibit junctions with the ECM called a “fibronexus”
Where in the PDL are fibroblasts found?
In the central part of the ligament
Why are the junctions between the PDL fibroblasts and the collagen in the extracellular matrix important?
Because they allow a functional link between the occlusal forces that impinge on the extra cellular matrix and the interior of the cell, specifically the cytoskeleton.
All three junctions have a link to the ________ & ultimately interact with he _____ in the extracellular matrix.
Actin cytoskeleton
Collagen
________ are distributed homogeneously through the PDL when ____, _____ & ______ are not.
Fibroblasts
Cementoblasts, Osteoblasts and Osteoclasts
Where are osteoblasts and osteoclasts found?
At the interface of the PDL and Bone.
How can Osteoclasts be identified?
they have multiple nuclei
______ are not like fibroblasts, they do not equally participate in synthesis & degradation of the ECM, instead they participate mainly in synthesis,
Cementoblasts
T or F, Cementum is resistant to resorption.
True! Only happened in special situations such as shedding.
What are Epithelial rest of Mallasez?
Remnants of HERS found in the periodontal ligament closer to the cementum than the bone. * may form cysts during inflammation.
________ are another important population of cells in the PDL and lie close to blood vessels and are thought to give rise to new fibroblasts, osteoblasts and cementoblasts.
Undifferentiated Mesenchymal cells (stem cells)
What is a Cementicle?
A spherical calcified mass found in the otherwise soft CT of the PDL.
What does the term Principal fiber group refer to?
Collagen fibers that are organized into bundles that function to attach cementum to the adjacent alveolar bone.
Alveolar crest fiber group = ?
cementum to crest (top) of alveolar bone.
Horizontal fiber group = ?
Cementum to alveolar bone below crest
Oblique fiber group = ?
(most numerous) cementum to alveolar bone, oblique orientation.
Apical fiber group = ?
Apex of tooth to alveolar bone socket
Interradicular fiber group = ?
Only in multirooted teeth: between cementum & interradicular septum of alveolar bone.
The Transeptal fiber group = ?
(gingival ligament) cementum of tooth 1 - over alveolar crest - to 2nd tooth.
