Structure of Periodontium

Question 1

what is periodontium

Answer 1

tissues that supports tooth

Question 2

What are the calcified connective tissues present in periodontium

Answer 2

Cementum

Alveolar bone

Question 3

what are the non calcified tissues present in Periodontium?

Answer 3

Lamina propria

Perio. Ligament

Question 4

what is cementum

Answer 4

covering the root of a tooth that attaches the teeth to the alveolar bone by anchoring the periodontal ligament.

Question 5

What is alveolar bone aka?

Answer 5

lamina dura

Question 6

what is lamina propria

Answer 6

underlying connective tissues

Question 7

What is line drawn at alveolar crest?

Answer 7

boundary between lamina propria and PDL

Question 8

what do all 4 connective tissues have?

Answer 8

major matrix of type 1 collagen

Question 9

what happens in Perio. disease?

Answer 9

periodontal tissue loss

alveolar bone degredation

Question 10

what does mastication need?

Answer 10

occlusion and accuracy from wear of opp. teeth

Question 11

What has periodontium evolved for ?

Answer 11

Shock absorber= protect enamel on crown

Allows continuous teeth eruption

Question 12

What is lamina propria

Answer 12

fibrous connective tissue that insert into tooth and bone of alveolar crest

Question 13

what do lamina propria fibres do?

Answer 13

hold attached gingiva to tooth

- attachment of gingiva to cuff= gingiva cuff

Question 14

properties of junction epithelium?

Answer 14

non keratinised
stratitified squamous epitheliume
external/ internal basal lamina
upper surface= bond between gingiva and enamel

Question 15

what do fibres below Junc. epithelium do ?

Answer 15

maintain strength of junction between tooth & gingiva

Question 16

where does basal lamina deposit?

Answer 16

on enamel via hemi-desmosomes

Question 17

what is free gingiva made of?

Answer 17

Oral epithelium
sulcular epithelium
Junction epithelium
connective tissue

Question 18

What is cellular cementum

Answer 18

forms first and thin cover over whole root

Question 19

what is accelular cementum

Answer 19

forms late and at root apex

Question 20

What cells do cementum have?

Answer 20

Within= cementocytes

line surface= cementoblasts

Question 21

what do cementoblasts do?

Answer 21

produce cementum matrix

Question 22

what is matrix of cementum ?

Answer 22

HAP (found in bone/dentine/enamel)

intrinsic/extrinsic fibres- type 1 collagen

Question 23

Cementum comp?

Answer 23

65%= inorganic
23%= organic
12%= water

Question 24

What 3 forms of Cementoenamel junction ?

Answer 24

1) cementum overlaps= 70%
2) butt join= 20%
3) gap between , dentine exposed so inc. sensitivity and caries = 10%

Question 25

what are incremental lines in cementum?

Answer 25

Lines of Salter

Question 26

what's between cementoblasts and mineralised cementum?

Answer 26

pale layer of unmineralised pre cementum

Question 27

why does thickness of pre cementum constant?

Answer 27

matrix deposited on inner and periodontal surface at same rate

Question 28

What fibres can insert into cementum from unmineralised PDL?

Answer 28

Sharpeys fibres where becomes mineralised in cementum

Question 29

what was inserted fibre into cementum once called?

Answer 29

extrinsic fibres

Question 30

what are extrinsic fibres formed?

Answer 30

Periodontal fibroblasts

Question 31

what is mineralised matrix between extrinsic fibres?

Answer 31

Intrinsic cementum via cementoblasts

Question 32

What cells are in the periodontium?

Answer 32

Fibroblasts - cementoblasts - osteoblasts - osteoclasts - epithelial cells - macrophages

Question 33

What is matrix in periodontium?

Answer 33

Collagen ground substances Glycoproteins/proteoglycans oxylatin

Question 34

What are small islands of epithelial celss?

Answer 34

cell rests of Malassez= remnant of development process of tooth root

Question 35

What are principal fibres?

Answer 35

bundles of collagen fibrils

Question 36

what is between collagen fibrils?

Answer 36

proteoglycans/glycoproteins

Question 37

what are the 5 collagen fibre types?

Answer 37

``` Alveolar crest fibres Horizontal fibres Oblique Apical Inter-radicular ```

Question 38

what are alv. crest firbes?

Answer 38

run from alveolar crest to inser into cementum

Question 39

what are horizontal fibres?

Answer 39

bone to tooth

Question 40

what are oblique fibres?

Answer 40

radiate from root apex

Question 41

what are inter-radicular fibres?

Answer 41

multirooted tooth fibres run from inter radicular bone | - bone beneath roots

Question 42

How are principle fibres formed?

Answer 42

tropocollagen> 5 membered microfibrils> classical fibrils> bundles> principle fibre bundles

Question 43

What are oxytalan fibres ?

Answer 43

immature elastin fibres

Question 44

what is the cellularity of periodontal ligament?

Answer 44

- many cell nuclei | - many fibroblasts= for connective tissues

Question 45

What are fibroblast features?

Answer 45

high RER for protein production | - high turnover rate for collagen

Question 46

how do periodontal ligament fibroblast degrade collagen?

Answer 46

phagocytic process

Question 47

what are rests of malassez?

Answer 47

leftover of tooth development processes

Question 48

what do PDL macrophages have?

Answer 48

microvilli lysozymes little RER or golgi

Question 49

what is the periodontal blood supply?

Answer 49

from superior and inferior alveolar artery

Question 50

what are the origin of capillaries in PDL?

Answer 50

Vessels in apex of tooth, intrabony spaces within alveolar

Question 51

what do capillaries in PDL form?

Answer 51

arterioles in gingivae

Question 52

what do capillaries/arterioles form?

Answer 52

plexus around socket wall

Question 53

what are features of Periodontal capillaries?

Answer 53

fenestrations for efficient diffusion/filtration

Question 54

What channels in socket wall called?

Answer 54

Volkmann's canals- carry vessels between ligament & intrabony spaces so blood to ligament