eruption and shedding

Question 1

define eruption

Answer 1

movements a tooth takes to attain and maintain its postion in the jaw

Question 2

tooth will move in all directions except

Answer 2

apically

Question 3

cell types of the PDL involved in eruption

Answer 3

fibroblasts, cementoblasts, osteoblasts, and osteoclasts

Question 4

fibroblast

Answer 4

most numerous cell in the PDL. many fns:

1. secretes ec substance
2. lysis of ec substance
3. contracting cell=fibromyocyte (connected to collagen fibers and when contracts, pulls on the collagen fibers to move the tooth)

Question 5

stages of eruption

Answer 5

1. preemergence
2. prefunctional
3. functional

Question 6

preemergence stage main direction of movement

Answer 6

facially

Question 7

preemergence stage starts with

Answer 7

appearance of dental lamina–>bud–>cap–>tooth germ–>REE and HERS. prior to root dentin formation

Question 8

function of HERS

Answer 8

1. determines root dentin outline

2. determine number of root canals

Question 9

number of root canals is determined..

Answer 9

in preemergence stage via the diaphragm of HERS. 1,2,or3 openings

Question 10

the bone crypt undergoes remodeling into the alveolar process in what stage

Answer 10

preemergence

Question 11

prefunctional stage of eruption main direction of movement

Answer 11

occlusally

Question 12

prefunctional stage of eruption

Answer 12

starts with root dentin formation and ends when tooth reaches the occlusal plane. merger (of oral epithelium and REE?)–>emergence (merged tissues undergo cell death). HERS elongates (to determine root outline), root dentin forms, HERS starts to break up at the CEJ, cementoblasts move in to form cementum on exposed dentin…this continues apically.

Question 13

what are epithelial rests of malassez

Answer 13

remanents of epi cells from HERS in the PDL. appear during the pre-fn stage of eruption

Question 14

during the pre-fn stage of eruption, REE becomes the

Answer 14

junctional epithelium (attached to the enamel and the cementum). has 2 basal lamina (1 connects to enamel and cementum, 2 connects to the c.t)

Question 15

formation of the PDL and alveolar process occurs in which stage of eruption

Answer 15

preemergence

Question 16

in the preemergence stage, how are PDL collagen fiber bundles arranged

Answer 16

obliquely..not functionally

Question 17

functional stage of eruption direction of movement

Answer 17

mesially…physiologic mesial drift

Question 18

functional stage of eruption

Answer 18

starts at the occlusal plane and physiologically continues throughout life. JE attachment position changes (e–>e&c–>c). functional arrangement of fiber bundles of PDL occurs.

Question 19

changes during fn eruption

Answer 19

attrition, dead tracts, reparative dentin, continued dentin formation, reduced pulp, ectopic mineralization

Question 20

reciprocal induction occurs b/w what two tissues in the fn stage of eruption

Answer 20

JE and the lamina propria/c.t

Question 21

define shedding

Answer 21

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

Question 22

odontoclasts originate in the

Answer 22

bone marrow