Periodontium

Question 1

What structures are part of the periodontium?

Answer 1

cementum, alveolar bone, gingiva, periodontal ligament

Question 2

What does the periodontal ligament contain?

Answer 2

it is an organised connective tissue therefore - cells (fibroblasts), extracellular matrix, fibres, nerves, blood vessels

Question 3

Which are the main cells found in the periodontal ligament?

Answer 3

Fibroblasts

Question 4

What components make up the periodontal ligament matrix?

Answer 4

Hyaluronate glycosaminoglycans, proteoglycans, glycoproteins

Question 5

What property does the periodontal ligament matrix have that enables it to stretch and return to its original shape?

Answer 5

behaves as a viscous elastic gel

Question 6

What cells are found in the periodontal ligament?

Answer 6

Fibroblasts, cementoblasts, osteoclasts, cementoclasts, epithelial cells (called cell rests/debris of Malassez), defence cells

Question 7

What is the name given to the epithelial cells in the PDL?

Answer 7

Cell rests or debris of Malassez

Question 8

Function of the cell rests/debris of Malassez

Answer 8

Form cysts

Question 9

Which cells participate in bone remodelling?

Answer 9

Osteoclasts

Question 10

Function of bone remodelling

Answer 10

Regulates Ca2+ concentration and important for orthodontics

Question 11

Which sensory receptors are found in the PDL?

Answer 11

mechanoreceptors and nociceptors

Question 12

Function of mechanoreceptors

Answer 12

detects fibre, thickness and consistency of food. e.g. allows a different chewing mechanism for different foods

Question 13

Function of nociceptors

Answer 13

Detect pain. Responsible for the jaw-jerk reflex

Question 14

Which part of the nervous system controls vasoconstriction/blood vessels?

Answer 14

Autonomic (sympathetic)

Question 15

Which 2 ligaments make up the periodontal fibres?

Answer 15

True periodontal ligament and gingival ligament

Question 16

What is the true periodontal ligament?

Answer 16

Fibres that connect the tooth to the alveolar bone at or apical to the alveolar crest

Question 17

What is the gingival ligament?

Answer 17

Fibres mainly above the alveolar crest, including free gingival fibres. Don’t connect to both the tooth and the alveolar bone, just connect to either one.

Question 18

Function of the periodontal ligament

Answer 18

Attaches the tooth to the jaw, transmits biting forces to the alveolar bone where it dissipates, and has a sensory role (jaw-jerk reflex and chewing).

Question 19

What is the approximate width of the PDL?

Answer 19

0.2mm

Question 20

How is the width of the PDL measured?

Answer 20

Periodontal space is measured via a radiograph.

Question 21

What is the name of the ligament that connects the tooth to the alveolar bone?

Answer 21

Alveolo-dental ligament

Question 22

Which periodontal ligament connect the cementum of adjacent teeth?

Answer 22

Interdental ligament

Question 23

Which fibre groups make up the alveolo-dental ligament?

Answer 23

Alveolar crest, horizontal, oblique, apical, inter-radicular (multi-rooted teeth)

Question 24

Which fibres make up the interdental ligament?

Answer 24

trans-septal fibres

Question 25

Examples of treatments that remove the PDL?

Answer 25

Implants, dentures

Question 26

Why are patients who have had the PDL removed at risk of fracturing the prosthetic?

Answer 26

The mechanoreceptors and nociceptors have been removed and the sensation is transferred to less reliable sources (TMJ and mucosa). Difficulty establishing food texture.