Periodontium 3

Question 1

The PDL is __________ tissue.

Answer 1

Soft connective tissue

Question 2

What are the major component of the PDL?

Answer 2

• highly organized collagen fibers

Question 3

What is the thickness of the PDL?

Answer 3

0.2-0.4mm *Gets thinner with age

Question 4

What are the cells of the PDL?

Answer 4

• Fibroblasts (Most common)
• Cementoblasts
• Osteoblasts
• Osteoclasts
• Epithelial cells
• Epithelial rest of Mallasez
• stem cells

Question 5

______ cells are responsible for both secreting and degrading collagen.

Answer 5

fibroblasts (they are very active cells in the PDL)

Question 6

What are the cell-to-cell contacts of the PDL fibroblasts?

Answer 6

• Desmosomes
• Gap Junctions
• Fibroblasts also exhibit junctions with the ECM called a “fibronexus”

Question 7

Where in the PDL are fibroblasts found?

Answer 7

In the central part of the ligament

Question 8

Why are the junctions between the PDL fibroblasts and the collagen in the extracellular matrix important?

Answer 8

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.

Question 9

All three junctions have a link to the ________ & ultimately interact with he _____ in the extracellular matrix.

Answer 9

Actin cytoskeleton

Collagen

Question 10

________ are distributed homogeneously through the PDL when ____, _____ & ______ are not.

Answer 10

Fibroblasts

Cementoblasts, Osteoblasts and Osteoclasts

Question 11

Where are osteoblasts and osteoclasts found?

Answer 11

At the interface of the PDL and Bone.

Question 12

How can Osteoclasts be identified?

Answer 12

they have multiple nuclei

Question 13

______ are not like fibroblasts, they do not equally participate in synthesis & degradation of the ECM, instead they participate mainly in synthesis,

Answer 13

Cementoblasts

Question 14

T or F, Cementum is resistant to resorption.

Answer 14

True! Only happened in special situations such as shedding.

Question 15

What are Epithelial rest of Mallasez?

Answer 15

Remnants of HERS found in the periodontal ligament closer to the cementum than the bone. * may form cysts during inflammation.

Question 16

________ 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.

Answer 16

Undifferentiated Mesenchymal cells (stem cells)

Question 17

What is a Cementicle?

Answer 17

A spherical calcified mass found in the otherwise soft CT of the PDL.

Question 18

What does the term Principal fiber group refer to?

Answer 18

Collagen fibers that are organized into bundles that function to attach cementum to the adjacent alveolar bone.

Question 19

Alveolar crest fiber group = ?

Answer 19

cementum to crest (top) of alveolar bone.

Question 20

Horizontal fiber group = ?

Answer 20

Cementum to alveolar bone below crest

Question 21

Oblique fiber group = ?

Answer 21

(most numerous) cementum to alveolar bone, oblique orientation.

Question 22

Apical fiber group = ?

Answer 22

Apex of tooth to alveolar bone socket

Question 23

Interradicular fiber group = ?

Answer 23

Only in multirooted teeth: between cementum & interradicular septum of alveolar bone.

Question 24

The Transeptal fiber group = ?

Answer 24

(gingival ligament) cementum of tooth 1 - over alveolar crest - to 2nd tooth.

Question 25

What type of collagen is found it the PDL?

Answer 25

Type I & III (80:20)

Question 26

T or F, Collagen turnover in the PDL is slow.

Answer 26

False, It has a fast turn over!

Question 27

________ are immature elastic fibers are found in the ligament and tend to run at right angles to the collagen fiber bundles.

Answer 27

Oxytalin

Question 28

The ground substance of the ECM of PDL’s is ______.

Answer 28

Proteoglycans and Associated GAG’s

Question 29

What is the glycoprotein that forms the ECM component ?

Answer 29

Fibronectin

Question 30

The ends of the collagen fibers that are inserted into mineralized tissue are called ________.

Answer 30

Sharpey’s fibers

Question 31

What are the fiber groups of the Gingival ligament?

Answer 31

• 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

Question 32

T or F, The PDL has profuse vascular supply.

Answer 32

True, the main vascular supply comes from the superior and inferior alveolar arteries.

Question 33

The PDL is highly innervated by ______, _____ & ____.

Answer 33

Ab and small Adelta and C fibers.

Question 34

_______ signal proprioception in addition to pain.

Answer 34

Sensory

Question 35

_____ Signals non-painful forces that impact teeth.

Answer 35

AB fibers

Question 36

Pain signals are carried principally by _____ & ______.

Answer 36

Adelta and C fibers

Question 37

The bone apical to the Alveolar process is called ______..

Answer 37

Basal bone

Question 38

The Alveolar process is composed of 3 types of bone?

Answer 38

• Outer cortical bone
• a central region of “spongy” or “trabecular” bone
• Bone lining the socket

Question 39

The bone lining the alveolar socket is called….

Answer 39

bundle bone, cribiform plate, lamina dura.

Question 40

What does the bone lining the alveolar socket develop from?

Answer 40

from the dental follicle

Question 41

What layer lines the bone socket?

Answer 41

lamina dura