Tooth Development Flashcards
Beginning Steps post Fertilization
fertilization - zygote to blastocyste, with embryoblast and tropoblast
Ectoderm
considered epithelium becomes epidermis skin CNS and tooth enemel
Neural Crest Cells
The the junction migrate from tip to underlying mesenchymal layer to form head neck CT dentin and support structures
Endoderm
epithelium gut tube
mesoderm
one of the layers forms blood vessels bone and CT
Ectomesenchyme
derived from cret forms dentin cementum PDL and alveolar bones
primary epithelial Band
Proliferated at site of dental arches with two subdivision
two subdivisions after primary epithelial band
dental lamina - horshoe shape of eptithelium where develop jaw
Vestibular lamina cells - will build up and breakdown to form the vestibule
Interactions between these two will dictate progression through the steps
Ectoderm (major keys)
is epithelium folded into embryo as anterior of oral cavity. No blood Supply to epithelial receoived from ectomesenchyme
what are the four stages
initiation bud cap bell
enamel organ
epithelium ingrowth from dental lamina will become enamel
dental papilla
is condensing ectomesenchyme will be dentin and pulp
dental folical /sac
around the lateral lamina tooth give rise to cementum pdl and alveolar bone
Stage I Bud Things
The tooth bud grows into ectomesenchyme
Builds cells are proliferating
Stage II cap Stage
Invagination of deep surface start to see neamel organ forming See dental papilla Dental Follicle and Enamel Organ
Two regions of enamel organ
center really hydrated cells pulling appart and held by desmosomes, are stellate reticulum
inner enamel epithelium
Adjacent to the dental papilla give rise to ameloblasts
Stratum intermedium
between inner enamle epithelium and stellate reticulum withs with inner to form enamel
outer nemal epithelium
on the other side of the enemal organ does not make enamel
Stage III the bell stage
see the four section of outer enamel epithelium stellate reticulum stratum intermedium and inner dental epithelium
Cervical Loop
the inner and outer epitheluim continous loop they bend this will become hertwigs root sheath to make root
Bell Stage Things that ahppend
dental lamina and lateral lamina degenerate
loose connection with oral cavity, (like now there is stuff over it)
shape begins and crown forms final shape
what happens if lateral and dental lamina dont degnerate
get cysts
why can we break through epithelium
junctional epithelium anchoring of basal lamina to tissue allows tight protection from things
Blood supply in dental papilla
diromg cap phase also the dental sac is vascular
Hard tissue formation
first dental papilla form odontoblasts. This is initiated by inner enamel epithelium to form dentin. Then the odontoblasts signal the inner dental epitehlium to be epithelium to form enamel
What hard tissue is always first
There is recipricol induction odontoblasts always first
inner enamel epithelium - signal and making of dentin
signals under induction from preamelioblasts cells become columnar and odontoblasts
odontoblast secrete predentin and take 1 day to make dentin
Direction of dentin secretion
moves towrad papilla, with apical processes residing in the dentinal tubules
PRedentin staingin
much paler staingin
Ameloblast signaling
odontoblasts signal ameloblast to secrete enamel enamel is secete and mineralizaed almost immediately and it moves away fro mbllod suppl y
with time the layers of dentin impede on blood supply so enamel stop
what is lost with tooth eruption
ameloblast
what happens at enamel full thickness
stratum intermedium stellate reticulam and enamel epithelium form the papillary layer, tTogether with the ameloblast for the reduced dental epithelium
Reduced dental epithelium
the ameloblast and papillary layer thin layer over the enamel
Fate of dental folicle
formef by the suport tissues form cementoblasts PDL and alvoelar bone
Periodontal Ligament formation
from the follicle (ectomesenchym)
connective tissue is collagen I and has high rate of turnover
Tooth eruption
tooth covered by reduced enamel epithelium
bone is resorbed before and so is CT over the tooth to reduce blood
reduced epithelium and oral epithelium fuse
central epithelium breaks in advance
break thorugh with the robust colar to protect
dentinogingival junction becomes junctional epithelium of gingiva
