What is the physiological process that occurs during the initiation stage of tooth development?
Induction
The Pow wow, let's get this party started, cells decide who they are going to be, the part we don't understand.
Induction
controlled levels of cellular growth
proliferation
cells start to be structurally and functionally different
differentiation
the tissues start to become structures
morphogenesis
growing up in form function and size
maturation
tooth development
odontogenesis
Dentition
teeth
20 baby teeth that develop during the prenatal period. Will be shed.
primary dentition
True or False. flouridation matters when teeth are forming in the womb.
true
32 adult teeth that develop during the fetal period-though they mature for years after birth. Will replace baby teeth.
secondary dentition
Does flouridation help adults?
not really
overlapping of time between primary and secondary dentitions.
mixed dentition
What other 2 physiological processes take place during the initiation stage of tooth development, but not as prevelant as induction?
proliferation
differentiation
What layers exist on the maxillary and mandibular arches during the initiation stage of tooth development?
Oral epithelium
Ectomesenchyme
basement membrane
top layer that comes from the ectoderm
oral epithelium
bottom layer of mesoderm that originally came from the ectoderm
ectomesenchyme
the "velcro" separating the oral epithelium from the ectomesenchyme
basement membrane
describe the development of the dental lamina layer.
for each tooth, the oral epithelium grows deeper into the ectomesenchyme (into a "finger-like projection") and forms the new layer called the dental lamina
starts as oral epithelium and grows down to a new layer with "fingerlike projection"
Dental Lamina
what are 3 developmental disturbances that occur during the initiation stage of tooth development?
anodontia
hypodontia
supernumerary teeth
absence of teeth. Nobody told them to grow. lack of initiation
anodontia; initiation stage
Less than normal amounts of teeth
hypodontia; initiation stage
extra teeth, somebody told them wrong
supernumerary teeth; initiation stage
the second stage of tooth development
bud stage
What physiological process occurs during the bud stage?
proliferation only
What happens during the bud stage of tooth development? The reason for the name of the stage.
The finger like projection full of dental lamina undergoes extensive proliferation, starts to fatten up and look like a bud.
What are some developmental disturbances that may take place during the bud stage?
Macrodontia
Microdontia
Big teeth
Macrodontia; bud stage
little teeth
microdontia; bud stage
third stage of tooth development
cap stage
what physiological processes occur during the cap stage?
proliferation
morphogenesis
differentiation
The predominant physiological process during the cap stage
morphogenesis
What causes the Cap shape of the dental lamina during the cap stage?
unequal proliferation
During the cap stage, the cells start differentiating to become____________and___________different
structurally
functionally
Name the 3 layers that are formed during the cap stage.
enamel organ
dental papilla
dental sac
comes from the dental lamina and will produce enamel
enamel organ
comes from ectomesenchyme and will be the future pulp and dentin
dental papilla
ectomesenchyme that will be the periodontium (cementum, periodontal ligament, and alveolar bone) the support structure
dental sac
enamel organ, dental papilla, and dental sac combined
tooth germ
the finger-like projection that will be the adult tooth
succesional dental lamina
the adult teeth that replace the baby teeth
succedaneous
the adult teeth that don't replace the baby teeth, they form brand new with out a previous tooth, not successors
nonsuccedaneous
what are 3 developmental disturbances that occur during the cap stage?
dens in dente
gemination
fusion
tooth within a tooth the enamel organ gets lost in the dental papilla
dens in dente; cap stage
single tooth unsuccessfully tries to split in two. Large single rooted tooth with two crowns, may look like macrodontia, but we only count roots
gemination; cap stage
two tooth germs that fuse together. It looks like macrodontia, or even some anodontia because you can't see enough crowns, but count the roots
fusion; cap stage
What is the 4th stage of tooth development?
Bell stage
What physiological stages are occuring during the bell stage?
proliferation
differentiation
morphogenesis
what physiological process is occuring to its furthest extent during the bell stage? And what forms as a result of it?
differentiation
many new layers
What are the new layers that form during the bell stage as a result of extensive differentiation?
outer enamel epithelium
stellate reticulum
stratum intermedium
inner enamel epithelium
basement membrane
outer cells of dental papilla
inner cells of dental papilla
protective barrier during enamel formation
outer enamel epithelium
star shaped cells that support enamel production
stellate reticulum
compressed layer of flat cells that support enamel production
stratum intermedium
will become enamel secreting cells (ameloblasts)
inner enamel epithelium
the velcro between inner enamel epithelium and outer cells of dental papilla, will become the dentinoenamel junction
basement membrane
will become the dentin secreting cells (odontoblasts)
outer cells of dental papilla
will become the dental pulp
inner cells of dental papilla
What stages of teeth development follow the bell stage?
apposition and maturation stages
growth by layers, layers of dentin, cementum, and enamel to be exact
apposition
enamel secreting cells that retreat to the north (away from the basement membrane)
ameloblasts
dentin secreting cells that retreat to the south (away from the basement membrane)
odontoblasts
describe the formation of the matrix.
The layers on either side of the basement membrane, the ameloblasts and odontoblasts, retreat and leave a slimy trail, the matrix
structure of ameloblasts that secretes the actual enamel matrix
tome's process
during which stage is the matrix, the structural foundation, mineralized?
maturation stage
what happens to ameloblasts with tooth eruption?
they are discarded
attached cellular extensions left by odontoblasts
odontoblastic processes.
Odontoblastic processes that are contained and protected in mineralized cylinders of dentin
dentinal tubules
what happens to the cell bodies of odontoblasts with tooth eruption?
they remain in the dental pulp
faulty development of enamel. pitting and grooves in the enamel
enamel dysplasia; apposition and maturation stages
decreased quantity of enamel matrix
enamel hypoplasia; apposition and maturation stages
(could result from flourosis
plenty of enamel matrix, but the quality was bad because it didn't fully mineralize
enamel hypocalcification; apposition and maturation stages
What are the 2 main metabolic or hereditary causes of enamel hypoplasia and enamel hypocalcification?
syphilis
flourosis
too much fluoride during mineralization
fluorosis
very thin or no enamel. hereditary, results in extreme attrition
amelogenesis imperfecta; apposition and maturation stages
faulty development of dentin. hypoplasia or hypocalcification
dentin dysplasia
blue-grey or brown teeth because the dentin didn't form correctly. the enamel (though healthy) chips off because it doesn't have support. results in attrition
dentinogenesis imperfecta
When does root development start?
when crown is complete and erupting
The IEE and OEE squished together - without the stellate reticulum or stratum intermedium.
Cervical loop
As the cervical loop extends deeper into the ectomesenchyme it becomes the____________.
Hertwig's epithelial Root Sheath (HERS)
HERS_____________the dental papilla to____________________ into odontoblasts.
induces
differentiate
How come enamel doesn't form during root formation of the tooth?
because there is no stratum intermedium or stellate reticulum, so ameloblasts cannot form
what do the odontoblasts do once they are formed?
they undergo dentinogenesis and begin to secrete predentin, the dentin matrix
What happens to the HERS when root dentin formation is completed?
it disintegrates, because of lack of ameloblasts
lost epithelial cells that fail to disintegrate with the rest of the HERS that can become cystic and cause problems
epithelial rests of Malassez
What is it that induces the cells of the dental sac to become cementoblasts?
After the disintegration of HERS, when the undifferentiated cells of the dental sac come in contact with the newly formed surface of root dentin.
cementum producers
cementoblasts
cementum production
cementogenesis
enamal production
amelogenesis
dentin production
odontogenesis
slimy trail left by cementoblasts, or cementum matrix
cementoid
cell bodies left in the matrix by cementoblasts
cementocytes
Why are the cell bodies of cementoblasts left in the matrix, or cementoid?
because the matrix was laid so quickly that the cell bodies got trapped or caught in the matrix
why do the cementoblasts line up with the periodontal ligament upon finishing the matrix?
so they are ready to lay more cementum if it ever gets broken down
the dental papilla is formed into the pulp of the tooth through____________.
induction
ectomesenchyme from the dental sac_____________into the _______________ adjacent to the cementum
differentiates
periodontal ligament (PDL)
Where does the periodontal ligament anchor itself?
into the cementum and alveolar bone
How are multirooted teeth formed?
cervical loop splits into multiple roots
ameloblasts get lost and start forming enamel in abnormal places, they may be confused with calculus on the root surface
enamel pearls; root formation
two teeth get stuck together by the cementum. Can be caused by trauma or crowding of teeth. Really hard to extract
concrescence; root development
because of injury or pressure, HERS gets distorted and makes the roots bend. Hard to extract
dilaceration; root development
extra roots because of injury, pressure, or metabolic disease of HERS
accessory roots; root development
actual vertical movement of tooth
active eruption
gingiva recedes around tooth
passive eruption
enamel organ squished together, fuses to the oral epithelium of the oral cavity, and disintegrates some of the oral epithelium to make a tunnel of eruption
Reduced Enamel Epithelium (REE)
inflammatory response caused by the disintegration of oral epithelium because of the REE.
teething
symptoms of teething
bleeding
inflammed gums
slight fever
portion where the epithelial tissues peel back, but remain intact around the cervical portion of the tooth during tooth eruption that creates a seal between the tissue and the tooth surface
initial junctional epithelium
dissolve the bone around the tooth
osteoclasts
dissolve the roots of the tooth (break down dentin)
odontoclasts
Why do kids teeth feel really loose and then suddenly tighten up again sometimes?
because sometimes the tooth is not ready to come out, so the osteoblasts, odontoblasts, and cementoblasts will replace the resorbed bone and root
left over REE and oral epithelium that sticks to the newly erupted teeth and catches stain
Nasmyth's membrane
All succedaneous teeth form and erupt__________________to the primary teeth, except the maxillary incisors that erupt______________to the primary teeth.
lingually
facially
the REE forms a cyst around the completely formed crown. It can displace teeth and cause pain. Must be removed surgically
dentigerous cyst; eruption
a dentigerous cyst formed around the developing crown. When the tooth erupts it will go away.
