Eruption and Shedding

Question 1

Eruption definition

Answer 1

The movement a tooth makes to attain and maintain its position in the jaw

Question 2

T/F - Tooth movement only occurs as it is erupting

Answer 2

False - Tooth movement occurs throughout life

Question 3

What direction(s) does a tooth move to attain and maintain its position in the jaw?

Answer 3

All directions, except apically

Question 4

Why type of activity is involved in movements of eruption?

Answer 4

Cellular activity involving different cell types of the periodontal ligament (PDL)

Question 5

What is the most numerous cell type of the PDL contributing to tooth movements?

Answer 5

Fibroblast

Question 6

What are the functions of a fibroblast within the PDL?

Answer 6

Secrete extracellular substance (fibroblast)
Lysis extracellular substance (fibroclast)
Contracting cell (fibromyocyte)

Question 7

What is a fibromyocyte myofibroblast?

Answer 7

A cell connected o collagen fiber bundles that connect the tooth to the alveolar bone
When it contracts, the collagen fibers contract, moving the tooth

Question 8

What are the stages of eruption?

Answer 8

Preemergence
Prefunctional
Functional

Question 9

When does the Preemergence occur?

Answer 9

Before the start of root formation

Question 10

What is the main tooth movement direction during the Preemergence stage?

Answer 10

Facially (however, they move in all different directions, but the net movement is facial)

Question 11

What appears during the preemergence stage?

Answer 11

Reduced enamel epithelium

Question 12

What attaches the reduced enamel epithelium to the enamel?

Answer 12

Basal lamina

Question 13

Cervical loop

Answer 13

Outer and inner epithelial layers coming together to form Hertwig’s epithelial root sheath

Question 14

Functions of Hertwig’s epithelial root sheath

Answer 14

Determines how many root canals

Determines the root-dentin outline

Question 15

What about Herwig’s epithelial root sheath determines root canals?

Answer 15

The number of openings in Hertwig’s diaphragm

Question 16

When does the prefunctional stage occur?

Answer 16

Begins with root dentin formation and ends when the tooth reaches the occlusal plane

Question 17

What is the main tooth movement direction of the Prefunctional stage?

Answer 17

Occlusally

Question 18

What happens to Hertwig’s epithelial root sheath during the Prefunctional stage

Answer 18

The sheath covers the root dentin, the apical end continues as the diaphragm, and the sheath breaks up

Question 19

Epithelial rest of Malassez

Answer 19

Remnants of epithelial cells from Hertwig’s epithelial root sheath in the PDL
Appear during prefunctional stage of eruption

Question 20

What happens to reduced enamel epithelium during the prefunctional stage?

Answer 20

The merged oral epithelium and reduced enamel epithelium undergo cell death

Question 21

When does functional stage of eruption occur?

Answer 21

When the tooth reaches the occlusal plane and continues throughout life

Question 22

What is the main tooth movement direction during the Functional stage?

Answer 22

Mesially

Question 23

What happens to the PDL during the funcitonal stage?

Answer 23

Functional arrangement of principal fiber bundles occurs

Question 24

What happens to junctional epithelium during the functional stage?

Answer 24

It changes position

Question 25

Shedding

Answer 25

The physiologic elimination of primary teeth caused by the resorptive action of odontoclasts

Question 26

What causes shedding

Answer 26

Odontoclastic activity

Question 27

Odontoclasts origin

Answer 27

Bone marrow and goes to the site of activity via blood vessels

Question 28

Odontoclasts

Answer 28

Resorb the 3 mineralized tissues of teeth

Question 29

What stage does odontogenesis begin?

Answer 29

Preemergence

Question 30

What stage do Ameloblasts, odontobalsts, and fibroblasts differentiate?

Answer 30

Preemergence

Question 31

What stage does the crown dentin appear?

Answer 31

Preemergence

Question 32

What stage does enamel formation and maturation begin?

Answer 32

Preemergence

Question 33

What stage is the DEJ established?

Answer 33

Preemergence

Question 34

What stage does the reduced enamel epithelium appear?

Answer 34

Preemergence

Question 35

What stage does the pulp chamber appear?

Answer 35

Preemergence

Question 36

What stage is Hertwig's epithelial root sheath form?

Answer 36

Preemergence

Question 37

What stage is the number of root canals determined?

Answer 37

Preemergence

Question 38

What stage does the bone crypt form?

Answer 38

Preemergence

Question 39

Bone crypt

Answer 39

Undergoes remodeling and becomes the alveolar process

Question 40

What stage does the root dentin form?

Answer 40

Prefuncitonal

Question 41

What stage does Hertwig's epithelial root sheath break up?

Answer 41

Prefunctional

Question 42

What stage does the Epithelial rest of Malassez form?

Answer 42

Prefunctional

Question 43

What stage do cementoblasts differentiate and cementogenesis occur?

Answer 43

Prefunctional

Question 44

What stage does the PDL and alveolar process form?

Answer 44

Prefuncitonal

Question 45

What stage are the collagen fiber bundles of the PDL arranged obliquely?

Answer 45

Prefunctional

Question 46

What stage does the reduced enamel epithelium merge with the oral epithelium?

Answer 46

Prefuncitonal

Question 47

What stage does the tooth emerge into the oral cavity?

Answer 47

Prefunctional

Question 48

What stage does the reduced enamel epithelium become the junctional epithelium of the free gingiva?

Answer 48

Prefunctional

Question 49

What stage are the principal fiber bundles of the PDL functionally arranged?

Answer 49

Functional stage

Question 50

What stage is the alveolar process preserved?

Answer 50

Functional stage

Question 51

What stage is secondary and tertiary dentin formed?

Answer 51

Functional stage

Question 52

What is the junctional epithelium movement during the functional stage?

Answer 52

It moves from its attachment to just enamel, to enamel and cementum, and then to just cementum