Periodontium

Question 1

what is the periodontium?

Answer 1

tissues surrounding and supporting the teeth

Question 2

what does the periodontium do?

Answer 2

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

Question 3

what is the junctional epithelium

Answer 3

the physical barrier separating the body tissues from the oral environment

Question 4

what does the cementum cover?

Answer 4

root dentine

Question 5

what is the structure of cementum?

Answer 5

collagen matrix and lamellar arrangement

Question 6

what does the cementum do?

Answer 6

provide attachment for some periodontal fibres

Question 7

what are the two types of cementum?

Answer 7

cellular and acellular cementum

Question 8

what is cementum laid down by?

Answer 8

cementocytes

Question 9

describe acellular cementum

Answer 9

no cells within, usually adjacent to dentine, first formed (primary cementum)

Question 10

describe cellular cementum

Answer 10

contains cementocytes, later formed (secondary cementum), present in apical part of root and in furcation regions

Question 11

which cementum type is primary cementum

Answer 11

acellular cementum

Question 12

which cementum type is secondary cementum

Answer 12

cellular cementum

Question 13

which type of cementum has sharpey’s fibres?

Answer 13

acellular extrinsic fibre cementum

Question 14

what does the alveolar bone do?

Answer 14

provides attachment for periodontal ligament fibres, supports the teeth

Question 15

what does the periodontal ligament contain?

Answer 15

cells, extracellular matrix, fibres, nerves, blood vessels

Question 16

what does the ground substance (matrix) of the PDL consists of?

Answer 16

hyaluronate GAGs, glycoproteins, proteoglycans

Question 17

what does the ground substance behave as?

Answer 17

viscoelastic gel

Question 18

what are the cells in the PDL?

Answer 18

fibroblasts, cementoblasts, osteoclasts and cementoclasts, defence cells, epithelial cells

Question 19

what type of sensory nerves are in the PDL?

Answer 19

mechanoreceptors and nociceptors

Question 20

what are the mechanoreceptors responsible for?

Answer 20

rapidly or slowly adapting, chewing control via proprioception

Question 21

what are the nociceptors responsible for?

Answer 21

protective reflexes, inhibit jaw elevator motor neurons

Question 22

what are the nervous systems in the PDL?

Answer 22

sensory and autonomic

Question 23

what is the autonomic responsibility in the PDL?

Answer 23

blood vessels control - vasoconstriction

Question 24

where does the PDL get the blood supply from?

Answer 24

inferior and superior alveolar arteries passing into the PDL, lingual and palatine arteries supplying gingivae

Question 25

what is the true periodontal ligament?

Answer 25

fibres connecting tooth to bone at or apical to alveolar crest

Question 26

what is the gingival ligament?

Answer 26

fibres mainly above the alveolar crest, including free gingival fibres

Question 27

what are the types of fibres in the PDL?

Answer 27

collagen, oxytalan

Question 28

what do collagen fibres in the PDL do?

Answer 28

support the tooth and load bearing

Question 29

what are the principle fibre groups in the alveolo-dental ligament?

Answer 29

alveolar crest, horizontal, oblique, apical, interradicular

Question 30

what are the principle fibre groups in the interdental ligament?

Answer 30

transseptal fibres

Question 31

what do the gingival fibres do?

Answer 31

support the free gingivae

Question 32

what is the effect of loading in the PDL?

Answer 32

tension in PDL fibres, compression of ECF