WEEK 6 - DENTINE + PULP

Question 1

what is dentine?

Answer 1

the mineralised tissue that forms the bulk of the tooth

Question 2

What happens to dentine throughout life?

Answer 2

it increases in thickness at the expense of the pulp

Question 3

what commences dentinogenesis

Answer 3

the formation of predentine by odontoblasts

Question 4

what does dentine consist of?

Answer 4

a large number of small parallel tubules in a collagen matrix

Question 5

what colour is dentine?

Answer 5

pale yellow

Question 6

Is dentine permeable?

Answer 6

yes

Question 7

What is the chemical composition of dentin?

Answer 7

70% inorganic, 20% organic, 10% water

Question 8

What is the inorganic component?

Answer 8

calcium crystals that give it its hardness

Question 9

what is the organic component of dentin?

Answer 9

collagen and ground substance

Question 10

What is the life cycle of odontoblasts?

Answer 10

preodontoblasts, secretory odontoblasts, resting odontoblasts

Question 11

What are the features of preodontoblasts?

Answer 11

small ovoid cells, high nucleus to cytoplasmic ratio

Question 12

What are the features of secretory odontoblasts?

Answer 12

large plump cell, open face nucleus

Question 13

What are the features of resting odontoblasts?

Answer 13

thin, quiescent state

Question 14

What are the 2 steps of dentinogenesis?

Answer 14

matrix formation and maturation

Question 15

what is matrix formation?

Answer 15

after the differentiation of odontoblasts, it secretes predentin

Question 16

what is the initial organic matrix (predentin) composed of?

Answer 16

small collagen fibrils and characteristic ground substance

Question 17

What is the maturation or mineralization of dentin?

Answer 17

the formation of calcium hydroxyapatite crystals in the form of globules in the predentin

Question 18

What are the two patterns of dentin mineralization that can be observed?

Answer 18

globular and linear calcification

Question 19

where is primary dentin located and what are its histological features?

Answer 19

it is formed before completion of apical foramen and more rapidly and mineralized than secondary dentin

Question 20

what is secondary dentin?

Answer 20

formed after completion of apical foramen, more slowly and less mineralized than primary. change of curvature

Question 21

what is tertiary dentin?

Answer 21

formed in response to trauma, an irregular course of tubules

Question 22

what are dentinal tubules?

Answer 22

odontoblast processes that run in canaliculi following an S shaped path

Question 23

what forms the main bulk of dentine?

Answer 23

intertubular dentin

Question 24

what is peri-tubular dentin?

Answer 24

highly calcified matrix

Question 25

what is interglobular dentin?

Answer 25

unmineralized dentin

Question 26

what is tomes granular layer?

Answer 26

seen just below the surface of dentin where the root is covered my cementum, a spotty microscopic line

Question 27

what are the incremental lines of dentin?

Answer 27

Lines of Von Ebner, counter lines of owen, and neonatal line

Question 28

what is incremental lines of von ebner?

Answer 28

long period lines associated with the five day deposition cycle.

Question 29

long period lines associated with the five day deposition cycle.

Answer 29

parallel imbrication lines

Question 30

What is the neonatal line?

Answer 30

a disturbance in mineralization from the trauma of birth

Question 31

what is serotic dentin?

Answer 31

injury or aging tooth

Question 32

What are dead tracts in dentin?

Answer 32

empty tubules from the death of primary odontoblasts

Question 33

what is the innervation of dentin?

Answer 33

in the pulp, 25% are myelinated afferents

Question 34

describe dentin hypersensitivity

Answer 34

odontoblasts act as receptors and fluid moves through tubules stimulating the receptors in the pulp

Question 35

what are the 3 theories associated with dentin hypersensitivity?

Answer 35

direct nerve stimulation, odontoblast process associated with sensation, an hydrodynamic theory

Question 36

what is pulp?

Answer 36

the soft connective tissue responsible for nourishing the dentine

Question 37

where is pulp contained?

Answer 37

pulp chamber

Question 38

what are the two main divisions of pulp?

Answer 38

coronal pulp and radicular pulp

Question 39

what is the largest and second largest group of cells in the pulp?

Answer 39

fibroblasts and odontoblasts

Question 40

what are the 4 zones of pulp?

Answer 40

odontoblastic layer, cell-free zone of Weil, cell-rich zone, pulpal core

Question 41

where is the odontoblastic zone of pulp located?

Answer 41

pulp perifery

Question 42

where is the cell free zone of weil located?

Answer 42

beneath odontoblasts, in coronal pulp

Question 43

where is the cell rich zone?

Answer 43

adjacent to cell free zone, in coronal pulp

Question 44

what is the pulp core?

Answer 44

the major vessels and nerves of the pulp

Question 45

what are the cells of the pulp?

Answer 45

odontoblast, fibroblast, macrophage, dendritic cell, lymphocyte, mast cell

Question 46

what does the extracellular component of the pulp consist of?

Answer 46

collagen fibres and ground substance

Question 47

what happens to collagen content in the pulp as you age?

Answer 47

increases

Question 48

what happens to pulp as you age?

Answer 48

gets smaller, less vascular, forms pulp stones

Question 49

what are pulp stones?

Answer 49

calcified masses of dentin

Question 50

what is dystrophic calcification?

Answer 50

originate in relation to blood vessels