normal periodontium :)

Question 1

components of the periodontoium

Answer 1

cementum
alveolar bone
PDL
gingivae

Question 2

cementum

Answer 2

part of tooth but functions for PD support

acellular and cellular

Question 3

alveolar bone

Answer 3

forms the tooth socket and attachment of PDL

Question 4

PDL

Answer 4

connects cementum and protects other PD structures

Question 5

diseases of the periodontium

Answer 5

gingivitis
- inflammation of gingiva
periodontitis
- inflammation of surrounding structres

Question 6

what is the cerviz

Answer 6

where the head and neck meet

- where the tooth begins to narrow

Question 7

what happens as the roots form

Answer 7

cementum and periodontal tissues develop from the dental follicle

Question 8

what does the alveolar bone form from

Answer 8

existing basal components of maxilla/mandible and surrounds the roots as it forms

Question 9

what produces the enamel on the crown

Answer 9

enamel organ

Question 10

what is underneath the EO

Answer 10

dental papilla

Question 11

what surrounds the EO and DP

Answer 11

dental follicle

Question 12

what are the components of the cervial loop

Answer 12

external dental epithelium
internal dental epithelium
- in the region of the cervix

Question 13

what happens as the cevcal loop grows deeper from th crown

Answer 13

grows into surrounding ectomesenchyme of dental follicle
encloses more of the DP as loop cell proliferates
forms Hertwigs epithelial root sheath
induces dentine formation

Question 14

what is the dental follicle

Answer 14

mesenchymal cells surrodunding from the developing teeth

Question 15

follicular cells of the DF are precursors to

Answer 15

fibroblasts
osteoblasts
cementoblasts

Question 16

what does the epithelial root sheath do

Answer 16

secretes a hyaline later

- induces cementoblasts and fibroblasts to differentiate from dental follicle

Question 17

where is the cervical loop found

Answer 17

lower part of the EO

- grows to form the roots of the teeth

Question 18

what does breakdown of the epithelial root sheath lead to

Answer 18

production of a network

- allows the root dentine to contact the follcile

Question 19

what is cementum

Answer 19

calcified connective tissue that covers root dentine

Question 20

what inserts into the cementum

Answer 20

periodontal fibre bundles

Question 21

what is cementum derived from

Answer 21

dental follicle (ectomesenchyme)

Question 22

properties of cementum

Answer 22

softer than dentine and more permeable
55% HAP and 45% organic matrix
avascular, no innervation
non labile

Question 23

types of cementum

Answer 23

acellular

cellular

Question 24

acellular

Answer 24

occupies cervical and middle root of root
very thin layer
no cells
featureless (but faint lines of sharpens fibres)

Question 25

cellular

Answer 25

occupies apical third of root (increases with age) cementocytes in lacunae forms more rapidly than acellular

Question 26

how do the cementycytes communicate in cellular cementum

Answer 26

communicate with each other through a network of canaliculi

Question 27

arrangement of the main fibres in cementum

Answer 27

from PDL embedded as sharpens fibres in the calcified martrix - incorporated the cememtum (extrinsic)

Question 28

how are main fibres arranged in acellular cementum

Answer 28

closely packed | mainly calcified

Question 29

how are main collagen fibres arranged in cellular cementum

Answer 29

widely spaced | partially calcified

Question 30

other collagen fibres within cementum

Answer 30

dense irregular network within matrix (intrinsic i.e. within cementum tissue) made by cementoblasts

Question 31

what does cementum provide

Answer 31

attachment for PDL fibres | - remains intact during orthodontics

Question 32

what is hypercementosis

Answer 32

excessive formation of cementum

Question 33

what causes hypercementois

Answer 33

hereditary | pagets disease

Question 34

what are small spherical masses on the PDL

Answer 34

cementicles

Question 35

what can cementum resorption occur due to

Answer 35

``` excessive occlusal stress orthodontic movement pressure from tumours or cysts Vit A/D deficiencies metabolic disease ```

Question 36

what is ankylosis

Answer 36

where the PDL is lost - leads to stiffening of joint - fusion of cementum of roots to alveolar bone, tooth becomes fixed

Question 37

how is the root connected to alveolar bone

Answer 37

PDL | - supports tooth in socket and absorbs loads on tooth

Question 38

what do the cells of the PDL d

Answer 38

maintain and repair alveolar bone and cementum

Question 39

alveolar bone

Answer 39

parts of maxilla and mandible that form the tooth sockets and support teeth

Question 40

when does the alveolar bone erupt

Answer 40

only develops as tooth erupts | resorbed if teeth are lost/extracted

Question 41

when is the alveolar bone absent

Answer 41

in anodontia (no teeth)

Question 42

what does the alveolar bone consitis of

Answer 42

buccal and lingual cortical plates of compact bone (cancellous between plates) cancellous bone is around the tooth forming the socket wall/inner cortical plate

Question 43

compact bone in alveolar bone

Answer 43

no hacersian systems | contains bundles of collagen from the PDL on internal aspect

Question 44

inner cortical plates

Answer 44

perforated vascualar has neural connections between the PDL and trabecular spaces

Question 45

bundle bone

Answer 45

collagen fibres of PDL insert into socket wall

Question 46

what does the inner cortical plate respond to and marked by

Answer 46

pressure -resportion tension - doposition marked by reversal lines

Question 47

what is the inner cortical bone also known as

Answer 47

bundle bone

Question 48

how does development of alveolar bone form

Answer 48

alveolar process forms label/buccal and lingual plates either side of the tooth organ

Question 49

where is interradicular bone found

Answer 49

in between roots of mutlirooted teeth

Question 50

what does alveolar bone respond to

Answer 50

mechanical stress and metabolic need for Ca and P

Question 51

types of tooth movement

Answer 51

pre eruptive movement eruptive tooth movement post eruptive movement

Question 52

how does bone remodelling occur

Answer 52

osteoclasts and osteoblasts

Question 53

what leads to eruption

Answer 53

due to growth factors released form dental follicle causing - resorption of overlying bone to create eruption pathway growth of alveolar bone

Question 54

what is needed to start alveolar bone formation

Answer 54

dental follicle secretes BMP 2 to induce osteoblasts

Question 55

how does exfoliation occur

Answer 55

pressure from underlying permanent tooth causes resprotio of dentine and cementum by osteoclasrs loss of PDL (mobile tooth) inflammation in ligament causes more resportion monocytes invade coronal part of dental follicle and convert to osteoclasts to create pathway

Question 56

what happens after an eruption pathway is made for exfoliation

Answer 56

DF secretes -CSF - monocyte chemotactic protein 1 - endothelial monocyte activating polypeptide 2 signal for secretion from stellate reticulum secreting - TGF beta 1 - Interleukin 1a basal part of DF stimulates alveolar bone growth providing the force moving tooth up (due to secretion of BMP2 stimulating osteoblast formation)

Question 57

pre eruptive tooth movemnt

Answer 57

made by tooth germs within the tissues of jaw before eruption - during crown formation - position changes with adjacent crowns and developing Md/Mx - all movements occur within the crypts before root formation

Question 58

eruptive tooth movment

Answer 58

made by a tooth from its position within the bone of jaw to its functional position in occlusion

Question 59

stages of eruptive tooth movemtn

Answer 59

root formation movement through any crypt to oral mucosa tip of crown penetrates though fused epithelial layers into the OC intraoral occlusal movement of erupting tooth until contacts opposing crown

Question 60

what happens in root format of eruptive tooth movemtn

Answer 60

proliferation of epithelial root sheath, initiation of root dentine and formation of pulp tissues of the root

Question 61

what happens when teeth move to reach the oral epithelium during eruptive tooth movemtn

Answer 61

Reduced enamel epithelium contracts and fuses with oral epithelium - a RE layer overlying the erupting crown arises from the REE

Question 62

post eruptive tooth movement

Answer 62

accommodate growing jaws compensate for occlusal wear accommodate inter proximal wear