eruption & shedding

Question 1

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

Answer 1

eruption

Question 2

the movements of eruption are a cellular activity involving different cell types of the _____

Answer 2

periodontal ligament (PDL)

Question 3

different cell types of the PDL

Answer 3

cementoblasts, osteoblasts, osteoclasts, and fibroblasts

Question 4

most numerous cell type of the PDL that is thought to play a key role in tooth movement

Answer 4

fibroblast

Question 5

functions of the fibroblast within the PDL:

Answer 5

1. secretes extracellular substance
2. lysis the extracellular substance
3. may become a contracting cell called a fibromyocyte myofibroblast

Question 6

a glycoprotein that exhibits elastic properties and serves as an integrin (similar to cell integrins) that binds to extracellular components such as collagen

Answer 6

fibronectin

Question 7

stages of eruption and main direction of movement

Answer 7

1. preemergence stage (facially)
2. prefunctional stage (occlusally)
3. functional (mesially)

Question 8

the preemergence stage starts with the appearance of the _____ and continues to the appearance of ____ and ____, just prior to the start of root dentin formation

Answer 8

dental lamina; reduced enamel epithelium; Hertwig’s root sheath diaphragm

Question 9

the number of ____ a tooth will have is determined during the preemergence stage

Answer 9

root canals

Question 10

the cervical loop is where outer and inner layers of enamel organ come together to form ____ during the preemergence stage

Answer 10

Hertwig’s epithelial root sheath

Question 11

the reduced enamel epithelium is attached to the completed enamel surface by a ____, the last secretion of ameloblasts

Answer 11

basal lamina

Question 12

2 main functions of Hertwig’s epithelial root sheath

Answer 12

1. determines the number of root canals of the tooth

2. determines the root dentin outline

Question 13

Hertwig’s root sheath determines ____ before the start of root dentin formation and _____ at the start of root dentin formation

Answer 13

number of root canals; root dentin outline

Question 14

the prefunctional stage of eruption starts with _____ and ends when tooth reaches _____

Answer 14

root dentin formation; occlusal plane

Question 15

Hertwig’s epithelial root sheath breaks up and _____ begins at cervical most part of root dentin

Answer 15

cementogenesis

Question 16

remnants of epithelial cells from Hertwig’s root sheath in the periodontal ligament; appear during prefunctional stage of eruption

Answer 16

epithelial rest of Malassez

Question 17

during the prefunctional stage of eruption, the merged _____ and _____ undergo cell death

Answer 17

oral epithelium; reduced enamel epithelium

Question 18

upon emergence into the oral cavity, the reduced enamel epithelium becomes the _____

Answer 18

junctional epithelium

Question 19

the functional stage of eruption starts at the ____ and physiologically continues _____; main movement is mesially, called _____

Answer 19

occlusal plane; throughout life; physiologic mesial drift

Question 20

____ attachment position changes during functional eruption

Answer 20

junctional epithelium

Question 21

functional arrangement of the _____ of the PDL occurs during the functional stage of eruption

Answer 21

principal fiber bundles

Question 22

changes during functional eruption:

Answer 22

attrition
dead tracts
reparative (tertiary dentin)
continued dentin formation
reduced pulp tissue volume
ectopic mineralization

Question 23

during the functional stage of eruption, ____ occurs between the junctional epithelium and adjacent connective tissue (lamina propria)

Answer 23

reciprocal induction

Question 24

shedding is caused by physiologic _____ activity

Answer 24

odontoclastic

Question 25

the odontoclast, like the osteoclast, originates in the ____ and is conveyed to the site of activity by ____ (odontoclasts resorb the 3 mineralized tissues of teeth)

Answer 25

bone marrow; blood vessels

Question 26

openings in the bone located lingual to the primary anterior teeth are called _____

Answer 26

gubernaculum canals