Tooth Development

Question 1

Autocrine

Answer 1

Self regulated- cell releases something that acts on its own receptors

Question 2

paracrine

Answer 2

cell talks to neighbor

Question 3

endocrine

Answer 3

release into the blood stream- talks to every one

Question 4

intracrine

Answer 4

signalling molecule never leaves cell-acts on self

Question 5

cell-matrix intereactions

Answer 5

dictate morphogenesis and differentiation

Question 6

Cranial neural crest derivatives

Answer 6

ganglia/ nerves, adrenal medulla, ectomesnchyme of bones and teeth

Question 7

Primary Epithelial Bands

Answer 7

mark sites of jaws

Question 8

Six stages of crown development

Answer 8

1) Initiation- induction
2) Bud Stage- proliferation
3) Cap Stage- Proliferation, diff. morphogenesis
4) Bell Stage- P, d, m
5) Apposition Stage- Induction and proliferation
6) Maturation Stage- maturation

Question 9

Bud Stage is precurser to

Answer 9

enamel organ

Question 10

Dental epithelium

Answer 10

controls what is going to happen

Question 11

Cap Stage

Answer 11

caused by unequal proliferation of bud cells
ectomesenchymal cells condense to become dental papilla and dental sac
tooth germ = enamel organ, dental papilla and dental sac
Successional dental lamina forms on lingual side of dental lamina ( will give rise to permanent tooth)

Question 12

Enamel knot

Answer 12

signalling center. found at base of enamel organ inside the cap shape

Question 13

dental papilla becomes

Answer 13

periodontia

Question 14

stellate reticulum

Answer 14

rich in GAGS

supports enamal production

Question 15

stratum intermedium

Answer 15

rich in alkaline posphatase,

supports enamel production

Question 16

Bell stage

Answer 16

Continued differentiation produces 4 distinct layers

1) outer enamel epithelium
2) stellate reticulum
3) stratum intermedium
4) inner enamel epthelium

Question 17

Cervical loop

Answer 17

junction of OEE (outer enamel epithelium) and IEE

this causes the shape and size of roots

Question 18

Outer Enamel Epthelium

Answer 18

protective barrier for enamel organ

Question 19

Inner Enamel Epithelium

Answer 19

differentiate into ameloblasts- enamel forming cells

Question 20

Apposition Stage

Answer 20

organic matrix of enamel and dentin are laid down followed by initial calcification- causes series of reciprocal inductions

1) IEE cells differentiate into preameloblasts- cells become polarized
2) preameloblasts induce outer DP cells to differentiate into preodontoblasts which become odontoblasts.
3) odontoblasts take off and basement membrane disintegrates (DEJ is formed)
4) predentin stimulates preameloblasts to become ameloblasts and retreat. (secretions immediately calcify to 25% full mineralization)

Question 21

Ameloblast Life Cycle

Answer 21

1) IEE Cell
2) Preameloblast- cell reverses polarity
3) Initial Secretory ameloblast- no Tomes process- prismless enamel
4) secretory ameloblast- Tomes process- enamel prisms
5) smooth-ended maturation ameloblast- removal of protein and water
6) ruffled-ended maturation ameloblast- introduction of inorganic material
7) preotective ameloblast- enamel cuticle

Question 22

Maturation Stage

Answer 22

Dentin is mineralizes as it is deposited , globular dentin produced first, then fuse together.
mantle dentin is closest to DEJ (higher mienral content, collagen fibers perpendicular to DEJ)
remaining dentin is circumpulpal dentin (lower mineral content and collagen fibers parralel to DEJ)