tooth development

Question 1

where does the ectomesenchyme come from?

Answer 1

neural crest

Question 2

what is the first stage of the ectoderm portion of teeth?

Answer 2

the dental lamina

Question 3

what germ layer(s) is/are teeth derived from?

Answer 3

ectoderm and ectomesenchyme (neural crest)

Question 4

where do the buds of permanent teeth grow relative to primary teeth?

Answer 4

ligually, although permanent molars are posterior

Question 5

what is the name for the buds of permanent teeth?

Answer 5

successional lamina

Question 6

What other lamina grow besides the dental and successional lamina?

Answer 6

vestibular lamina; forms the vestibule

Question 7

what is the bud stage?

Answer 7

the initial proliferation between the oral epithelium and the surrounding mesenchyme occurs

Question 8

between the mesenchyme and the epithelium, which is shaped like a bud?

Answer 8

the oral epithelium

Question 9

what does the oral epithelial layer become?

Answer 9

the enamel

Question 10

when does the bud stage become the cap stage?

Answer 10

when the epithelial bud becomes concave

Question 11

the mesenchymal layer that surrounds the epithelial bud layer is called?

Answer 11

the dental papilla

Question 12

what layer surrounds the dental papilla?

Answer 12

the dental follicle?

Question 13

what structures are seen in the cap stage?

Answer 13

dental papilla
enamel organ
dental follicle

Question 14

the dental papilla is a precursor what what tooth structure?

Answer 14

the dentin and pulp

Question 15

the dental follicle is a precursor what what tooth structure?

Answer 15

cementum, PDL and surrounding alveolar bone

Question 16

which are formed from the neural crest mesenchyme?

enamel
dentin
cementum

Answer 16

dentin and cementum,

both the dental papilla and follicle are from the neural crest

Question 17

what are two characteristics of the bell stage?

Answer 17

1) morphodifferentiation: the tooth structure is defined by the inner enamel epithelium and dental
2) the differentiation of the inner epithelial layer into ameloblasts

(cytodifferentiation also occurs)

Question 18

what structure lies above the ameloblasts?

Answer 18

stratum intermedium, plays a role in the mineralization of enamel

Question 19

in the bell stage, what makes up the enamel organ from out to in?

Answer 19

outer enamel epithelium
stellate reticulum (kinda all over the place)
stratum intermedium
inner enamel epithelium

Question 20

what is the cervical loop?

Answer 20

the place where the inner and outer enamel epithelium meet, will eventually become the cervix

Question 21

what is cytodifferentiation

Answer 21

the differentiation of the dental papilla into odontoblasts and enamel organ into ameloblasts

Question 22

if the epithelial and mesenchymal layers are separated, can they still form teeth?

Answer 22

no, each layer is somewhat dependant on each other

Question 23

which layer is giving the instructions?

Answer 23

in the beginning the epithelial layer gives the instructions, then later the mesenchyme takes charge

Question 24

what is the trigger for odontoblast differentiation?

diffusible molecules or
cell-cell contact

Answer 24

cell-cell contact

epithelial processes penetrate the basal lamina and cause differentiation