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.
What type of collagen is found it the PDL?
Type I & III (80:20)
T or F, Collagen turnover in the PDL is slow.
False, It has a fast turn over!
________ are immature elastic fibers are found in the ligament and tend to run at right angles to the collagen fiber bundles.
Oxytalin
The ground substance of the ECM of PDL’s is ______.
Proteoglycans and Associated GAG’s
What is the glycoprotein that forms the ECM component ?
Fibronectin
The ends of the collagen fibers that are inserted into mineralized tissue are called ________.
Sharpey’s fibers
What are the fiber groups of the Gingival ligament?
- Transeptal ligament = across teeth
- Circular = around tooth in lamina propria of free and attached gingiva.
- Dentogingival = most numerous cervical cementum - lamina propria of free & attached gingiva
- Dentoperiosteal = cementum - over alveolar crest - insert into other side of alveolar bone.
- Alveologingival = alveolar crest - lamina propria of free & attached gingiva
T or F, The PDL has profuse vascular supply.
True, the main vascular supply comes from the superior and inferior alveolar arteries.
The PDL is highly innervated by ______, _____ & ____.
Ab and small Adelta and C fibers.
_______ signal proprioception in addition to pain.
Sensory
_____ Signals non-painful forces that impact teeth.
AB fibers
Pain signals are carried principally by _____ & ______.
Adelta and C fibers
The bone apical to the Alveolar process is called ______..
Basal bone
The Alveolar process is composed of 3 types of bone?
- Outer cortical bone
- a central region of “spongy” or “trabecular” bone
- Bone lining the socket
The bone lining the alveolar socket is called….
bundle bone, cribiform plate, lamina dura.
What does the bone lining the alveolar socket develop from?
from the dental follicle
What layer lines the bone socket?
lamina dura
