Cementum

Question 1

Secondary cemetum is less or more mineralized than primary cementum?

Answer 1

less

Question 2

where are progenitors for 2ndary cementum likely from?

Answer 2

endosteum of alveolar bone

Question 3

where are progenitor cells for secondary cementum unlikely to be from?

Answer 3

from residual dental follicle cells in PDL

Question 4

Does primary cementum form before or after breakup of hertwigs epithelial root sheath?

Answer 4

after, the cells of dental follicle reach the root surface

Question 5

initially, cementoblasts insert processes into the

Answer 5

unmineralized hyaline layer

Question 6

does the hyaline layer mineralize before or after the mantle dentin?

Answer 6

after

Question 7

is the hyaline layer more or less mineralized than the cementum or dentin?

Answer 7

more

Question 8

what does the hyaline layer do?

Answer 8

“cements” cementum to dentin

Question 9

what does HERS do for the mantle dentin of the root?

Answer 9

induces it to form initially

Question 10

What percent of cementum is inorganic and organic?

Answer 10

60/40

Question 11

What do cellular cementum cementoblasts express that are bone like?

Answer 11

Type 1 collagen, alkaline phosphatases, osteocalcin,PTH cell surface receptors

Question 12

What can induce acellular cementum cementoblasts?

Answer 12

Epithelial derived molecules, like enamel proteins and emdogain

Question 13

Is the hyaline layer enamel like?

Answer 13

yes

Question 14

Primary acellular intrinsic fiber cementum, does not have a surface cementoid, and contributes minimum function of tooth attachment/ it Forms a ___ microm thick fibrous fringe to which PDL collagen fibers eventually connect via_____

Answer 14

15-20 microns thick, and relies on lysyl oxidase/Cu2+ crosslinking

Question 15

Primary acellular EXTRINSIC fiber Cementum constitutes the _____ of the primary cementum type and gets its collagen fibers from PDL fibroblasts. It extends from the CEJ towards the ___ of the tooth and covers about ____ of the coronal portion of the root. And it is relatively_____

Answer 15

Bulk of primary cementum type, goes to apex of root, covers 2/3 of the coronal portion of the root. It is relatively structureless

Question 16

The average thickness of primary acellular EXTRINSIC fiber cementum decreases/increases apically

Answer 16

increases

Question 17

Does Primary acellular EXTRINSIC fiber cementum contain cementoblasts? if so where are they? Is there a surface cementoid?

Answer 17

Yes it has cementoblasts, they migrate towards the PDL and ultimately reside on periphery, facing the PDL. It does NOT have a surface cementoid.

Question 18

Secondary cellular INTRINSIC fiber Cementum is a major/minor component o the 2ndary cementum fiber type, its is only found on anterior/posterior teeth, its only on the apical ____of the root or in the _____ area of multirooted teeth. It has/does not have a surface cementoid, and a miniamal function in tooth attachment.

Answer 18

It is a minor component, found variably but only in posterior teeth, located in apical 1/3 of root and in interradicular area of mutirooted teeth. it DOES have a surface cementoid.

Question 19

Secondary celullar MIXED fiber cementum constitutes the BULK of the 2ndary cementum type , it is also located at apical 1/3 of root, its microscopic features include….

Answer 19

cementocytes in lacunae, also have cell processes enclosed in canaliculi going towards PDL, lamellar/laminated structure, surface cementoid preset, no OSTEONs and no SYNCYTIUM formed by cell processes

Question 20

2ndary cellular MIXED fiber cementum is important because…

Answer 20

its variability is likely an indicator that it is required for adaptve function

Question 21

Whats the deal with acellular afibrillar cementum?

Answer 21

usually not found in humans its on enamel and its not supposed to be there really

Question 22

whats the deal with intermediate cementum? Where is it located? Does it have a function in tooth attachment? Hint: it collects garbage

Answer 22

its incorrectly called a synonym for the hyaline layer, its actually a for of Secondary Cellular INTRINSIC fiber cementum.it is only located at the apex of the tooth. It contains entrapped residual cell debris from either the HERS or the odontoblast layer. It does NOT have a function in tooth attachment

Question 23

What’s with mixed stratified cementum?

Answer 23

Consists of alternating layer of acellular EXTRINSIC and CELLULAR INTRINSIC cementum. Located at APEX , it functions in response to adaptive needs of the tooth.

Question 24

From inside to outside, what are layers of pulp to mantle dentin?

Answer 24

Pulp, tertiary dentin, secondary dentin (circumpulpal then mantle dentin)

Question 25

Is circumpulpal dentin thicker than mantle dentin? How thick is mantle dentin?

Answer 25

Yes it is thicker, mantle dentin is only 150 microns wide and lacks phosphophoryn protein

Question 26

Is mantle dentin more or less mineralized than the rest of the primary dentin?

Answer 26

less

Question 27

how wide is the hyaline layer?

Answer 27

ten microns

Question 28

is acellular cementum primary or secondary?

Answer 28

primary

Question 29

is cellular cementum primary or secondary?

Answer 29

secondary

Question 30

what is mean thickness of cementum as it increases apically? From CEJ to mid root to apex?

Answer 30

50 microns at CEJ
120-160 at mid root
200-250 at apex level

Question 31

what is HERS?

Answer 31

2 cell layer extension of reduced enamel epithelium that induces mantle dentin formation in root. Coronal aspect eventually deteriorates bc of breakup of basement membrane. HERS cells secrete hyaline layer adjacent to mantle dentin. HERS cells finally migrate towards PDL and die a little bit, leave epithelial cell rests of Malassez

Question 32

what are intrinsic fibers?

Answer 32

fully mineralized fibers that help organize mineralization process. Made by cementoblsts

Question 33

what are extrinsic fibers?

Answer 33

made by PDL fibriblasts to help connect root to alveolar bone