Development of Teeth

Which cells form enamel

oral epithelial cells

Which cells form dentin

mesenchymal cells of dental papilla

What do neural crest cells do

migrate to jaws, mix with mesenchymal cells

What is the first sign of a tooth

dental lamina

What does dental lamina become

sheet of epithelial cells forming tooth buds

How many primary tooth buds form

20

Where do adult teeth develop

lingual to primary teeth from successional lamina

Which adult teeth develop from successional lamina

anterior teeth and premolars

Which adult teeth develop from general lamina

molars

How do teeth develop in the jaw

anteroposteriorly

When do posterior molars develop

after space is available

When does second dentition form

after primary teeth are functional

Where do permanent teeth form

under primary crowns and behind primary molars

What happens in bud stage

epithelial cells grow, mesenchymal cells proliferate

What happens in cap stage

epithelial cells form enamel organ, mesenchymal cells form dental papilla

What surrounds enamel organ and dental papilla

dental follicle

What happens in bell stage

enamel organ develops outer/inner enamel epithelium, stellate reticulum appears

Which cells become odontoblasts

cells in dental papilla

What is predentin

collagen matrix laid by odontoblasts before calcification

Which comes first, dentin or enamel

dentin (dentinogenesis precedes amelogenesis)

How do odontoblasts and ameloblasts interact

ameloblasts induce odontoblasts, dentin forms first, then enamel

How does dental pulp form

blood vessels and nerves appear in dental papilla, becomes pulp as dentin forms

How does dentin form

odontoblasts lay predentin, calcifies in 24 hours

What is dentinal tubule

odontoblast process remains inside it

How does predentin calcify

crystals form on collagen, grow, and coalesce

When does amelogenesis begin

after dentin deposition

Which cells become ameloblasts

inner enamel epithelium

What are the five stages of ameloblast function

morphogenesis, organization, secretion, maturation, protection

What are Tomes’ processes

apical projections of ameloblasts during secretion

How is enamel matrix formed

made in RER, packaged in Golgi, secreted along DEJ

How does crown mineralization occur

enamel matrix deposited, mineral grows, protein matures to enamelin

When does enamel continue to mineralize

even after eruption

What is Hertwig’s root sheath

inner/outer enamel epithelium join, guide root formation

Which cells form root dentin

odontoblasts of dental papilla

What forms intermediate cementum

outer root sheath

What are epithelial rests of Malassez

leftover root sheath cells

What is the epithelial diaphragm

sheath at root apex encircling pulp opening

How does single root form

cementoblasts lay cementum on root surface after sheath breaks up

How do multiroots form

root sheath grows differentially in furcation zone

When do primary teeth develop

in utero

When do permanent teeth develop

at or after birth

What affects primary crown mineralization

prenatal disturbances

What affects permanent crown mineralization

postnatal disturbances

How long do primary teeth function

~8.5 years

How long is primary crown/root development

~1 year

How long for root maturation/resorption

~3.75 years

How long is shedding

~3.5 years

How long can permanent teeth function

7–8 times longer than primary teeth

What are dental follicle cells

mesenchymal cells around teeth

What do follicle cells form

alveolar bone and periodontal ligament

Which cells form periodontal ligament

fibroblasts from follicle

How are ligament fibers attached

cementum on root to alveolar bone

How does alveolar bone develop

keeps pace with root length, forms labial/lingual plates, septa between teeth