Tooth development Flashcards
Bell stage
Fourth stage of odontogenesis. Occurs between 11th-12th week of prenatal development.
Dental papilla
produces dentin & pulp for inner part of tooth
HERS
Hertwig epithelial root sheath.Induces dentin formation in root area
Enamel dysplasia (Maturation stage disturbance)
faulty development of enamel. Can be local or systemic
Bell stage
When does it occur?
signifigacne of bell stage
what else occurs?
Morphodifferentiation visable, start of reconisable tooth stage
around 14th week, occurs when a 4th layer of epithelium, stratum intermedium appears, cuboidal shaped
serves as a protective barrier for the rest of the enmeel organ during enamel production
Enamel organ develops an extention to the lngual side of each primary tooth germ
the origin of the ectomensenchymn are…
these cells are primary dervied from
they also give rise to…
derived from the nerual crest
ectoderm
mesenchymal tissues
odontogenseis
when it starts?
start of tooth develoment
starts 6th week after fertilisation
Dilaceration (Root formation disturbance)
distorted root(s) or severe associated crown angulation in formed tooth. Caused by distortion of HERS
Enamel organ
produces enamel on outer surface of crown
Avulsed tooth
tooth that is completely removed from socket due to trauma
Ameloblasts
being amelogenesis, appositional growth of enamel matrix
Microdontia (Bud stage disturbance)
Abnormally small teeth
Nonsuccedaneous
Pernament Molars
Supernumerary teeth (Initiation stage disturbance)
development of one or more extra teeth. most commonly between maxillary central incisors or distomolar
Bell stage of the enmel organ
The inner enamel epithelium lines:
Differenentated to:
Layer IEE and stellte reticulum
The outer enamel epithelium:
Capillaries:
the concavty of the bell stage
ameloblast
Stratum intermedium
line the periphery of the enamel organ
are near the outer enamel epitheiulm and bring nutrition for the cells of the enamel organ
the bud stage
When does this happen?
the first stage in development of the enamel organ that form the enamel of teeth
8 weeks
Dentin Dysplasia
Faulty development of dentin. interference with metabolic processes of odontoblasts
Fusion (Cap stage disturbance)
Union of two adjacent tooth germs. Two pulp cavities but one large crown
Oral epithelium (Initiation stage)
comes from outer part of ectoderm. consists of two horseshoe-shaped bands of tissue
Rests of Malassez
remnants of HERS. has potential to form cysts
Basement membrane (Initiation stage)
acellular structure that separates the oral epithelium and ectomesenchyme in the stomodeum
Gemination (Cap stage disturbance)
Single tooth germ tries unsuccessfully to divide into two tooth germs. Single rooted w/ one large pulp cavity and “twining” crown
Succedaneous
Permanent teeth that replace primary teeth. Anterior teeth & premolars
Enamel pearl (Root formation disturbance)
Small spherical enamel projections on tooth surface
ERM
Epithelial rests of Malassez. Cells become this after disintegration of root sheath
REE
reduced enamel epithelium
Enamel hypoplasia
type of enamel dysplasia. results from a reduction in quantity of enamel matrix
Accessory roots
extra root on tooth
Dental lamina (initiation stage)
7th week. produced by oral epithelium growing deeper into ectomesenchyme
Cap stage
Third stage of odontogenesis. Occurs between 9th-10th week of prenatal development (fetal period). Morphogenesis
Initiation stage
first stage of tooth development. involves induction (interaction between embryologic tissues)
Bud Stage
second stage of odontogenesis, occurs at 8th week. Proliferation of dental lamina into buds
Masmyth membrane
green-gray residue
Cervical loop
Responsible for root development
Amelogenesis Imperfecta
certain type of enamel dysplasia
Rests of Serres
Remnants of dental lamina
Enamel hypocalcification (Turner tooth)
“sparkle spot” white area, or white tooth
Passive eruption
occurs with aging when gingival tissue recedes but no actual tooth movement takes place
Dentinogenesis
appositional growth of dentin matrix. forms dentin
How many dental lamina?
the cells are sent in bunches, 10 maxillary and 10 mandibular
Stellate reticullum
where is it?
physical properties
located in the centre of the enamel organ of a devloping tooth. star-shaped. they synthesis glycominoglycans (sugars). water is draw between cells and strech them apart. as they move further away fom each other they stay connected through desmosomes, resulting in their star appearnce
Macrodontia (Bud stage disturbance)
Abnormally large teeth
Tubercles (Cap stage disturbance)
small, round enamel extensions forming extra cusps
Dental Lamina
the thickened oral epthelium that grows downward into the mesoderm.
Dentigerous cyst
Odontogenic cyst that forms from reduced enamel epithelium
Root dentin formation occurs
when outer cells of dental papilla in root area undergo induction and then differentiation and become odontoblasts
Cap stage
whats the layers
When does this happen?
cross section enanmel looks like a cap
consists of 3 layers : OEE, IEE, stellate reticulum
10 weeks
OEE
What is its function?
Looks like?
outer enamel epithelium
this is the protective layer for the enamel organ. later it plays a rolein attaching the gingiva to the tooth
they are cuboid shape
Odontoclasts
cause mainly primary tooth root respiration with the removal of dentin and cementum
tooth devlopment is interactions between…
the oral epithelium
and the ectomesenchyme cells
Ectomesenchyme (Initiation stage)
type of mesenchyme that is derived from neural crest cells.
The primative oral epithelium is dervived from
ectoderm
Ectodermal Dysplasia (Initiation stage disturbance)
abnormal development of skin, hair, nails, teeth, or sweat glands
Active eruption
vertical movement of tooth
Enamel Hypoplasia: Syphilis
Mullbury molars and Hutchinson incisors
Tomes process
responsible for laying down the enamel matrix into place
Dental Sac
capsule-like dental sac that produces the periodontium, cementum, PDL and alveolar process
Basement membrane during cap stage
between enamel organ and dental papilla. creates dentinoenamel junction
Apposition stage
enamel, dentin & cementum are secreted in successive layers
Odontogenesis
process of tooth development
IEE
Physical properties
Inner enamel epithelium
tall columnar shaped. these cells outline the concavity in the deepest part of the enamel organ. they are continious with the OEE and come from the basal layer of the oral epithelium
Maturation stage
Final stage of odontogenesis
Anodontia (Initiation stage disturbance)
Lack of initiation within lamina dura. Absence of tooth/teeth
Dentinogenesis Imperfecta
blue/gray or brown teeth
matrix
Extracellular substance that is partially mineralized. Serves as a framework for later full mineralization to the tissue type’s expected level
Cementogenesis
Occurs when the HERS disintegrates
Dens in Dente (Cap stage disturbance)
Enamel organ abnormally invaginate by growth into the dental papilla. Most common in lateral incisors
Tooth germ
At end of cap stage, enamel organ, dental papilla and dental sac come together and form this.
