WEEK 7 - CEMENTUM

Question 1

What are the hard tissues in the periodontium?

Answer 1

Cementum and alveolar bonevv

Question 2

What are the soft tissues in the periodontum?

Answer 2

periodontal ligament and gingiva

Question 3

what is the cementum?

Answer 3

attaches teeth to the alveolar process by anchoring the periodontal ligament

Question 4

Is cementum calcified?

Answer 4

yes

Question 5

what does the cementum protect?

Answer 5

open dentinal tubules within root dentin

Question 6

where is cementum the thickest?

Answer 6

apex

Question 7

Because of its mineral level cementum appears more _____ than enamel or dentin

Answer 7

radiolucent

Question 8

Because of its mineral level cementum appears more _____ than pulp

Answer 8

radiopaque

Question 9

where is the cementum permeable?

Answer 9

dentin and periodontal ligament sides

Question 10

what is the chemical composition of cementum?

Answer 10

50% inorganic and 50% organic

Question 11

what are some of the organic components of cementum?

Answer 11

collagen, glycoproteins, proteoglycans

Question 12

cementum contains the greatest amount of what in all mineralized tissues?

Answer 12

fluoride

Question 13

what are the 3 functions of cementum?

Answer 13

anchorage, adaptation, repair

Question 14

what allows for anchorage of the tooth within the osseous socket?

Answer 14

sharpey fibres

Question 15

what is adaptation of cementum?

Answer 15

cellular cementum compensates for tooth wear that causes tooth eruption to facilitate contact with opposing tooth

Question 16

how is repair achieved by the cementum?

Answer 16

cellular cementum

Question 17

what is the first step of cementogenesis?

Answer 17

production of predentine by odontoblasts leads to the breakdown of HERS (Hertwig epithelial root sheath)

Question 18

what is the second step of cementogenesis?

Answer 18

mesenchymal cells of dental sac differentiate into cementoblasts which deposit collagen fibrils, leading to pre cementum formation

Question 19

describe the incremental growth of cementum

Answer 19

as one layer of pre cementum is formed, the old one calcifies and becomes cementum

Question 20

what type of cementum is the first one formed?

Answer 20

acellular cementum

Question 21

what does the acellular cementum cover?

Answer 21

entire root but mostly the cervical third of the root

Question 22

acellular cementum is also referred to as primary cementum because…

Answer 22

it consists of the first layers of cementum deposited at the dentinocemental junction

Question 23

how thick is the cementum?

Answer 23

20-50 microns

Question 24

what makes up the acellular cementum?

Answer 24

sharpeys fibres

Question 25

why is the cellular cementum considered the secondary cementum

Answer 25

it consists of the last layers of cementum

Question 26

what part of the root does the cellular cementum cover?

Answer 26

mostly the apical third

Question 27

how thick is cellular cementum?

Answer 27

150-200 microns

Question 28

which is more permeable cellular or acellular cementum?

Answer 28

cellular cementum

Question 29

which is formed faster, acellular or cellular cementum?

Answer 29

cellular

Question 30

cellular cementum consists of

Answer 30

cementocytes

Question 31

what are cementocytes enclosed with and what do they look like?

Answer 31

lacunae, processes in canaliculi directed toward the tooth surface

Question 32

which type of cementum can widen over time?

Answer 32

cellular

Question 33

what is intermediate cementum?

Answer 33

first cementum deposited on the roots surface formed by the inner epithelial root sheath cells

Question 34

where is the intermediate cementum situated?

Answer 34

between the granular dentin layer of tomes and the secondary cementum

Question 35

What is acellular afibrillar cementum?

Answer 35

coronal cementum with no cells or fibres

Question 36

what is acellular extrinsic-fiber cementum?

Answer 36

covers cervical third to half of roots surface with no cells and contains sharpey fibres

Question 37

what is cellular intrinsic-fiber cementum?

Answer 37

fills resorption lacunae, contains cells but no fibers

Question 38

what is cellular mixed stratified cementum?

Answer 38

covers apical portions of roots surface and contains cells, intrinsic fibres and sharpey fibres

Question 39

what are incremental lines of salter

Answer 39

unevely spaced incremental lines formed by the formation of cementum

Question 40

how do incremental lines of salter differ in acellular cementum?

Answer 40

closer together, thinner, and even

Question 41

what are incremental lines of salter made out of?

Answer 41

hypermineralized areas with less collagen and more ground substance.

Question 42

what are the three types of interfaces on the cemento-enamel junction

Answer 42

overlap, meet and gap

Question 43

what percent of the CEJ overlaps the enamel?

Answer 43

60%

Question 44

what percent of the CEJ meets end to end with enamel?

Answer 44

30%

Question 45

what percent of the CEJ forms a gap, leaving exposed dentin?

Answer 45

10%

Question 46

how does the cementum change with age?

Answer 46

it becomes more irregular, and cementum resorption occurs.

Question 47

what is cementum resorption?

Answer 47

the progressive loss of cementum and dentine by odontoclasts

Question 48

cementum resorption has periods of repair. the deposition of new cementum forms a

Answer 48

reversal line

Question 49

what are cementicles?

Answer 49

Mineralized spherical bodies of cementum found either attached to the cemental root surface or lying free in the PDL

Question 50

what is the origin of cementicles?

Answer 50

epithelial cells, occur during ageing or trauma

Question 51

What is hypercementosis?

Answer 51

excessive production of cellular cementum

Question 52

what are the clinical considerations of hypercementosis?

Answer 52

difficult extraction