Periodontium

Question 1

what is the peridontium?

Answer 1

tissues supporting and surrounding the teeth

Question 2

what are the functions of the peridontium?

Answer 2

• retain tooth in socket
• resist masticatory loads
• defensive barrier, protecting tissues against threats from oral environment

Question 3

what is the physical barrier separating the body tissues from the oral environment?

Answer 3

the junctional epithelium

Question 4

what are the different periodontal tissues?

Answer 4

• gingiva
• periodontal ligament
• alveolar bone
• cementum
• tooth itself

Question 5

where is the cementum located?

Answer 5

covers the root dentine

Question 6

what is the function of cementum?

Answer 6

provides attachment for some periodontal fibres

Question 7

what are the two types of cementum known as?

Answer 7

1. cellular cementum

2. acellular cementum

Question 8

what cells lay down cementum?

Answer 8

cementocytes

Question 9

what type of cementum is formed first?

Answer 9

acellular cementum

Question 10

where is acellular cementum found?

Answer 10

usually adjacent to dentine

Question 11

what cells are found in cellular cementum?

Answer 11

cementocytes

Question 12

what type of cementum is formed later/second?

Answer 12

cellular cementum

Question 13

where is cellular cementum found on the tooth?

Answer 13

• apical part of root

- furcation regions

Question 14

what cementum has a role in a tooth attachment?

Answer 14

Acellular extrinsic fibre cementum

Question 15

found in the alveolar bone, what does the cortical plate that forms the inner lining of the tooth socket provide?

Answer 15

provides attachment for periodontal ligament fibres (Sharpey’s fibres)

Question 16

what occurs to the alveolar bone when the teeth are lost?

Answer 16

the alveolar bone is resorted

Question 17

what type of tissue is the periodontal ligament? what does it contain?

Answer 17

a connective tissue containing =

• cells
• ECM
• fibres
• nerves
• blood vessels

Question 18

what are the functions of the periodontal ligament?

Answer 18

• attaches tooth to jaw

- transmits biting forces to alveolar bone

Question 19

what cells are found within the PDL?

Answer 19

• fibroblasts
• cementoblasts
• osteoclasts & cementoclasts
• epithelial cells
• defence cells

Question 20

what is found within the extracellular matrix?

Answer 20

• hyaluronate GAGs
• glycoproteins
• proteoglycans

Question 21

what is the function of the ECM?

Answer 21

acts as a viscoelastic gel

Question 22

what types of nerves are located within the PDL?

Answer 22

sensory and autonomic nerves

Question 23

what sensory nerves are found within the PDL?

Answer 23

> mechanoreceptors (Abeta and Adelta fibres)

> nociceptors (Adelta and C fibres)

Question 24

what is the function of nociceptors within the PDL?

Answer 24

• protective reflexes

- can inhibit jaw elevator motor neurons

Question 25

what autonomic nerve function does the PDL have?

Answer 25

blood vessel control

Question 26

what is the blood supply of the PDL?

Answer 26

• from inferior and superior alveolar arteries passing into PDL from alveolar bone
• from lingual and palatine arteries supplying gingivae

Question 27

what is the ‘gingival’ ligament ?

Answer 27

fibres mainly above the alveolar crest (including free gingival fibres)

Question 28

what types of fibres are found in the PDL?

Answer 28

• collagen (types I and III)

- oxytalan fibres

Question 29

what is the function of collagen fibres within the human PDL?

Answer 29

support tooth & load bearing

Question 30

when might the PDL be subjected to intrusive forces?

Answer 30

• mastication
• swallowing
• speech
• parafunction (clenching/grinding)