Tooth Development - Rougier Flashcards
Arch 1 is innervated by CN
V
arch 2 is innervated by CN
VII
During the _____ week of development thickenings of oral epithelium develop, overlying the future dental arches in the upper and lower jaws
6th
The dental lamina lies _______ (in coronal section) to the vestibular lamina; it has a horseshoe shape in its entirety
medial
The buds plus the closely-associated ectomesenchyme represent the primordia of the ________ teeth
deciduous
All the buds are present by the _____ week
8th
Development of cells that form dental tissues is the process of
histodifferentiation
At what month in development does the cap-like configuration
3rd
The cap-shaped epithelial proliferation is now identified as the _________ which has/forms what 4 things?
enamel organ
- inner enamel epithelium
- outer enamel epithelium
- SR
- SI
The enamel organ is _______ and lacks ________
avascular ; innervation
what is responsbile for formation of enamel
the enamel organ
the ______ is a condensation of ectomesenchymal tissue lying within the concavity of the enamel organ
dental papilla
once dentinogenesis is initiated, the dental papilla will become
vascularized and innervated
the cells of the dental papilla give rise to _____ and _____
dentin ; pulp
The ______ is a thickening of
ectomesenchymal tissue that encompasses the enamel
organ and dental papilla
dental follicle (or sac)
the dental follicle (sac) gives rise to what 3 things
cementum
PDL
alveolar bone
Cells of the inner enamel epithelium become tall
columnar cells. They are on their way to becoming
enamel-producing cells, the
ameloblasts
until production of enamel begins, you should actually view ameloblasts as what?
preameloblasts
In their preameloblast stage the inner enamel epithelial
cells induce neighboring ectomesenchymal cells of the
dental papilla to differentiate into dentin producing cells,
the ______
odontoblasts
we see development of the tooth buds for the permanent teeth, excluding the _____ in the _____ stage
molars ; bud
Because the molars don’t have decidious predecessors, the the tooth buds for permanent molars develop from
posterior extensions of the dental lamina
during the bell stage, the cells of the ____________ begin to degenerate. Over time,
this will create a furrow that forms the
vestibular lamina ; oral
vestibule
Dentinogenesis begins in the occlusal region of the future crown, where the newly differentiated odontoblasts produce
predentin
Predentin is the ___ matrix of dentin
organic
Mineralization of predentin forms ____ which encloses
the cytoplasmic process in a ______
dentin ; dentinal tubule
As the odontoblasts migrate centrally, a layer of predentin will ______ be present
always
enamel formation begins with mineralization of
dentin
preameloblasts are induced to complete their differentiation into ameloblasts by the
presence of
mineralized dentin
The simultaneous formation of enamel and dentin
is termed the _____ stage
appositional
As preameloblasts
differentiate, they induce differentiation of _______
and _______
odontoblasts ; dentinogenesis
dentinogenesis induces
completion of the differentiation of _______ and
_______
ameloblasts ; amelogenesis
The dynamics of dentin and enamel formation are an example of
reciprocal induction
Once enamel formation achieves its definitive thickness the ameloblasts regress. They combine with the other layers of the enamel organ to form a protective cellular coating known as the
reduced enamel epithelium
Crown formation for deciduous teeth is completed during the year
first
The root of the tooth is comprised of
dentin
cells of the inner enamel epithelium will also induce differentiation of _____ for root formation
odontoblasts
neural crest cells migrate into the pharyngeal arches and mix with mesenchyme to produce ______ to help form teeth
ectomesenchyme
what is the embryonic period
fertilization through 8 weeks
Initiation is signaled by development of the
dental lamina
a thickening of oral epithelium overlying ectomesenchyme
dental lamina
the _________ segment gives rise to maxillary incisors
intermaxillary
what is the forerunner of the dental and vestibular lamina
the primary epithelial band
developmental origin of oral epithelium is
ectoderm
what line separates ectoderm from ectomesenchyme (which has NCCs)
the primary epithelial band
differentiation of the primary epithelial band proceeds differentiation of
ectomesenchyme
what are the 6 events associated with tooth development
Initiation
Proliferation
Morphogenesis
Differentiation
Apposition
Eruption
what event associated with tooth development is:
dental lamina formation
initation
what event associated with tooth development is:
mitosis within dental lamina &
ectomesenchyme to establish tooth primordium
proliferation
what event associated with tooth development is:
changes of shape that lead to bud, cap, bell stages
Morphogenesis
what event associated with tooth development is:
formation of ameloblasts & odontoblasts
Differentiation
what event associated with tooth development is:
dentin & enamel formation
Apposition
what event associated with tooth development is:
root formation
eruption
the vestibular lamina is ALWAYS ______ to the dental lamina
labial
formation of dental lamina is also mirrored by the 2nd folding that is labial to it and called a
vestibular lamina
a thickening of oral epithelium (derived from ectoderm)
dental lamina
change of the plane of cleavage in cells of the epithelial band is the origin of the
dental lamina
tooth buds are derived from
ectoderm
tooth bud formation happens during the __ to __ week of development
6th - 8th
_______ tissue releases factors that stimulate development of
the tooth bud
Ectomesenchymal
The tooth bud becomes the enamel organ in the ____ stage
cap
the enamel organ has _____ origin
ectodermal
dental papilla is derived from ______ and “makes” ____ and _____
ectomesenchyme ; pulp ; dentin
dental follicle is derived from ______ and “makes” ____ , _____ , and _____
ectomesenchyme ; PDL ; cementum ; alveolar bone
The vestibular lamina lies ____ to the cap stage
lateral
the _______ is the beginning of all tooth cusps
enamel knot
the origin of all dental tissue is the
cervical loop
3 Important Events during the Bell Stage:
Configuration of the crown is determined
a successional lamina is formed, with permanent tooth buds
histodifferentiation: dentin and enamel formation will occur
formation of crown is determined during the _____ stage
bell
we have the beginning of our appositional stage during what stage
Bell
the sucessional lamina is always on the ____ side
lingual
during the late bell stage, the dental lamina will begin to atrophy internally and disconnect from the oral epithelium and develop a 2nd process called the
successional lamina
the successional lamina gives rise to
permanent dentition
10 primary teeth and 10 permanent teeth will develop in association with the initial
dental lamina
______ are first to mature and erupt
Incisors
Odontogenesis moves ______ as jaws develop and lengthen
posteriorly
In the bell stage, the configuration of the crown is
determined in sites where _______ ceases and causes buckling of the _____
mitotic activity ; IEE
There is histodifferentiation of cells of the IEE and Outer Dental Papilla (ODP) in
future cuspal area
Cells of the IEE begin organizing to form
preameloblasts
cells in IEE secrete growth factor that secrete into cells of the outer dental papilla which causes them to differentiate into odontoblasts which secrete
dentin
ameloblasts secrete a ________ matrix which eventually becomes ______
non-mineralized ; mineralized
what is the only tissue with a non-mineralized precursor
enamel
_______ are the first cells to reach functional maturity
Odontoblasts
the location of future cuspal edge is found in what stage
bell stage
1st tissue secreted by odontoblasts is _______ and the 1st mineralized tissue they secrete is _________ which begins in the _____ until it reaches the ________ and the ______ and then it is complete
pre-dentin ; dentin ; cusp ; cervical loop ; crown
Appositional stage begins in _____ regions and progresses in a cervical direction
cuspal
The interface where enamel and dentin meet is termed the _____
DEJ
Ameloblasts move _____ from the DEJ as enamel is formed
away
Odontoblasts migrate _____ developing pulp
into
Dentin and enamel formation extend in a ______ direction
cervical
Enamel formation stops when it reaches the
cervical loop
the enamel organ has NO _________
blood supply
When the full thickness of the enamel is achieved, the layers
of the enamel organ become compressed, forming the
reduced enamel epithelium
The REE also has as protective mechanism, separating the ______ from the _______
enamel ; ectomesenchyme