bds2 periodontium

Question 1

function of the periodontium

Answer 1

• retain tooth in the socket
• resist masticatory forces
• defensive barrier to protect tissues against threats from the oral environment

Question 2

what is junctional epithelium

Answer 2

physical barrier separating the body tissues from the oral environment

Question 3

describe acellular cementum

Answer 3

extrinsic fibre cementum
collagen fibres from periodontal ligament
cervical 2/3 of roots

Question 4

describe cellular cementum

Answer 4

intrinsic fibre cementum
intrinsic collagen fibres parallel to the surface
play no role in tooth attachment and this can represent a transitional form

Question 5

what is the cortical plate of alveolar bone

Answer 5

this is the part of alveolar bone that forms the inner lining of the tooth socket

Question 6

what are volkmanns canals

Answer 6

nutrient canals that penetrate the alveolar bone

Question 7

what is a residual ridge

Answer 7

when teeth are lost the alveolar process is resorbed and this leaves the ridge

Question 8

components of the periodontal ligament matrix include

Answer 8

hyaluronate glycosaminoglycans

glycoproteins eg fibronectin
proteoglycans eg proteodermatan sulphate, or chondroitin sulphate

Question 9

what is the main property of the periodontal ligament matrix

Answer 9

behave as a viscoelastic gel

Question 10

list the sensory nerves of the periodontal ligament

Answer 10

mechanoreceptors (a beta and a delta fibres)
- these are rapidly or slowly adapting
- responsible for proprioception and control of chewing

nociceptors (a delta and C fibres)
- protective reflexes to inhibit the jaw elevator motor neurons

Question 11

explain the sympathetic aspect of periodontal ligament innervation

Answer 11

blood vessel control and vasoconstriction

Question 12

explain the blood supply of the periodontal ligament

Answer 12

from the inferior and superior alveolar arteries, passing into the periodontal ligament from the alveolar bone

also comes from the lingual and palatine arteries to supply the gingivae

Question 13

what is true periodontal ligament

Answer 13

fibres connecting tooth to bone at/apical to the alveolar crest

Question 14

what is the gingival ligament

Answer 14

fibres mainly above the alveolar crest including free gingival fibres

Question 15

what is the width of the periondontal ligament

Answer 15

0.2mm

Question 17

function of oxytalan fibres in the periodontal ligament

Answer 17

present in the human periodontal ligament although the function is uncertain

Question 18

are there elastic fibres in the periodontal ligament of humans

Answer 18

no

Question 19

principle fibre groups in the alveolodental ligament

Answer 19

alveolar crest
horizontal
oblique
apical
interradicular ( only in multi rooted teeth )

Question 20

what are the principle fibre groups in the interdental ligament

Answer 20

the transseptal fibres

Question 21

describe the gingival fibre group

Answer 21

supports the free gingivae

Question 22

what are the intrusive forces that the periodontal ligament is subjected to

Answer 22

mastication
swallowing
speech
parafunction

Question 23

what are extrusive forces

Answer 23

sticky foods and orthodontic forces

Question 24

which two elements are the anchors of the periodontium

Answer 24

the tooth and the alveolar bone

Question 25

which tissue is the most complicated organised tissue in the body and why is that

Answer 25

the periodontal ligament because of the tissues associated with it

Question 26

what are the black dots in a ground section

Answer 26

where the cells once were

Question 27

which type of cementum is responsible for tooth attachment

Answer 27

acellulular

Question 28

where is acellular cementum absent

Answer 28

furcation regions

Question 29

what are the mechanoreceptors of the PDL associated with

Answer 29

fine tuning of the softness or hardness of the food being chewed

Question 30

which PDL fibres are only found in the multi rooted teeth

Answer 30

inter radicular

Question 31

which fibres cross the space and connect tooth to tooth

Answer 31

trans septal

Question 32

which fibres run around the tooth

Answer 32

alveologingival fibres

Question 33

what is the much gingival junction

Answer 33

the subdivision between attached gingiva and alveolar mucosa is called the mucogingival junction

Question 34

what is the length of the muco gingival junction relevant for

Answer 34

treatment and evaluating the progression of periodontal disease

Question 35

why should the lips be pulled back when taking an impression

Answer 35

to extend the alveolar mucosa to show a good picture of the muco gingival junction where the gingival is attached

Question 36

what is the enamel cuticle

Answer 36

decalcified section where enamel is removed. coating of enamel when the tooth is prepared and there is some remainder

Question 37

describe free gingiva

Answer 37

has a sulcus or crevice containing crevicular epithelium covering the sulcus. not attached to enamel to form the sulcus junctional epithelium is attached to the tooth and is the most important tissue to highlight as it attaches the gingiva to the tooth and has a special attachment - the basal laminate has one internal and one external with hemidesmosomes to organise the attachment of the epithelium to the enamel

Question 38

describe how oblique fibres attach

Answer 38

to the cementum, apically to the bone, cervically

Question 39

what are the main fibres in sharpeys fibres

Answer 39

collagen type I and III

Question 40

where is acellular cementum located

Answer 40

2/3 cervical region of the root

Question 41

where is cellular cementum

Answer 41

third apical region of the root and also found on furcation regions of multi rooted teeth

Question 42

where is acellular extrinsic fibre cementum

Answer 42

2/3 cervical region of the root

Question 43

where is cellular intrinsic fibre cementum located

Answer 43

third apical region of the root and furcation regions of multi rooted teeth

Question 44

where is cementum thicker

Answer 44

apical region

Question 45

describe the route of principle oblique fibres and the reason for this

Answer 45

wavy line form cementum to bone to provide further elastic resilience to the fibres as they transfer the energy from the tooth to the bone

Question 46

which cells are found at the surface of cementum

Answer 46

cementocytes

Question 47

what is the main cell type at the centre of the periodontal ligament

Answer 47

fibroblasts

Question 48

where are sharpey fibres bundled more closely

Answer 48

cementum, spread at the bone to dissipate masticatory forces and protect the bone

Question 49

what are the advantages of horizontal fibers

Answer 49

responsible for dealing with lateral forces that the tooth dissipates to the bone during masticatory excursions. powerful forces as you have to slide on tooth against the other as well as then cutting food

Question 50

why is changing the root rotational arrangement important

Answer 50

when teeth need to be rotated, the root rotation must be changed as horizontal fibres will be stretched and bring the tooth back if there is no maintenance to allow the fibres to rearrange themselves

Question 51

what is responsible for periodical cysts during tooth development

Answer 51

epithelial cell rests of malassez

Question 52

group of principle fibres attaching cementum from one tooth to the adjacent tooth.

Answer 52

Transseptal fibre

Question 53

Teeth cementum to gingiva

Answer 53

dento gingival fibres

Question 54

Teeth to connective covering of the bone and periosteum

Answer 54

dento periosteal

Question 55

Alveolar bone to gingiva

Answer 55

alveolo gingival

Question 56

what is the dento gingival junction

Answer 56

Boundary between the oral cavity and the underlying connective tissue of the tooth supporting tissues.

Question 57

why is oral gingival epithelium easiest to identify

Answer 57

due to keratin and functional role in mastication