Cementum

Question 1

what is cementum differentiated from

Answer 1

ectomesenchyme

Question 2

does cementum have blood supply or innervation

Answer 2

neither

Question 3

where is cementum thinnest

Answer 3

at the CEJ

Question 4

what are the structural components of cementum and percentages

Answer 4

-45-50% mineral
- 50-55% organic

Question 5

what does the organic material in cementum contain

Answer 5

type 1 collagen, proteoglycans, glycosaminoglycans, phosphoproteins

Question 6

what are the functions of the cementum

Answer 6

-provides attachment for PDL
- may provide limited compensation for occlusal wear through continuous apical apposition
-may participate in repair of root fracture

Question 7

where is cementum formed from

Answer 7

the inner zone of the dental folliclr

Question 8

what do perforations in hertwigs root sheath allow for

Answer 8

the growth factors to leak out and make contact with dentin to then induce differentiation

Question 9

describe depositional and reversal lines

Answer 9

indicate incremental growth and run from crown to apex

Question 10

what are cementocytes and describe each

Answer 10

lacunae- space occupied by cell
canaliculi- space occupied by cytoplasmic projections, help with intercellular communication

Question 11

what is the incidence rate of overlap, end to end, and gap between cementum and enamel

Answer 11

overlap-60%
end to end (30%)
gap (10%)

Question 12

why is a gap between cementum and enamel bad

Answer 12

it leaves exposed dentin and sensitivity

Question 13

what teeth are commonly affected in abfraction

Answer 13

single teeth with excursive interferences or eccentric occlusal loads

Question 14

what is abrasion

Answer 14

loss of tooth structure by wear of dental tissue caused by abrasion of a foreign substance (toothbrush)

Question 15

what teeth are affected in abrasions

Answer 15

canines and premolars in cervical areas

Question 16

what is attrition

Answer 16

tooth to tooth contact on occlusal surfaces

Question 17

what is a cementicle

Answer 17

calcified bodies appearing on or in the cementum and in the PDL

Question 18

what causes cementicles

Answer 18

response to local trauma or hyperactive occlusion and appear in increasing numbers and increase in age

Question 19

where are free cementicles, attached cementicles, and embedded cementicles found

Answer 19

free-floating around in the PDL
-attached- cememtum
-embedded- cementum

Question 20

what are cemental spurs and what causes them

Answer 20

projection of cementum in response to trauma

Question 21

why are cemental spurs bad

Answer 21

makes extraction hard

Question 22

what is hypercementosis

Answer 22

excessive production of cellular cementum that generally involves the apical 1/3 of the root

Question 23

what is the etiology of hypercementosis

Answer 23

trauma from occlusion, periapical inflammation, or compensation for occlusal attrition

Question 24

what does hypercemetosis result in

Answer 24

bulbous root structure

Question 25

why is cementum not supposed to be exposed to the oral cavity

Answer 25

due to perforations/rough surface/low mineral content

Question 26

how does periodontal disease cause bone loss and results in exposed cementum

Answer 26

-exposed cementum is hypermineralized which prevents reattachment of collagen
-exposed cementum facilitates attachment of plaque and calculus
-exposed cementum facilitates endotoxin absorption

Question 27

what is resorption and what is the cause

Answer 27

eating away of root surface. cause is unknown

Question 28

what is repair due to

Answer 28

accessory canals

Question 29

what do accessory canals allow for

Answer 29

vascular tissues to move and reach apical mineralized tissues

Question 30

where are accessory canals located in multi rooted teeth

Answer 30

most common in furcation

Question 31

where are accessory canals in single rooted teeth found and percentages in each

Answer 31

-near CEJ (1.6%)
-mid root (8.8%)
-apex (17%)