Odontogenesis Flashcards
What are the parts of the teeth?
-enamel
-dentin
-cementum
-pulp
What are the parts of the periodontium?
-gingiva
-PDL
-cementum
-alveolar bone proper
What are the stages of tooth developement?
-initiation
-bud stage
-cap stage
-bell stage
-apposition
-maturation
What occurs during initiation?
cellular induction
What occurs during the bud stage?
cellular proliferation
What occurs during the cap stage?
proliferation, differentiation, and morphogenesis
What occurs during the bell stage?
proliferation, differentiation, and morphogenesis
-see all different layers
What occurs during apposition?
induction and proliferation
What occurs during maturation?
maturation
-calcification
What type of tissue determines the fate of the neural crest cells?
epithelium
What does the mesenchyme determines about the teeth?
the type of tooth that it will become
What type of cell will form the enamel organ?
ectoderm
When does the induction stage of tooth development occur?
during the 6th and 7th weeks of development
How is the dental lamina formed?
the ectoderm invaginates into the mesenchyme
What separates the lamina from the surrounding mesenchyme?
basement membrane
What happens to the ectoderm during the bud stage?
the proliferating ectoderm transitions into dental lamina
When does the early cap stage occur?
9th-10th weeks
How does the buccal vestibule form?
because of apoptosis of cells
What is the stellate reticulum?
loose layer of cells that help to provide support to the epithelium
What will the dental sac help form?
the PDL, cementum, and alveolar bone
What is the cell type and the function of the OEE?
cuboidal cells
protective barrier
What is the cell type and the function of the IEE?
cuboidal cells
differentiate into ameloblasts
What is the cell type and the function of the stellate reticulum?
-star shaped cells forming network inside enamel organ
-supportive function in enamel production
What is the cell type and the function of the stratum intermedium?
compressed layer of flat cuboidal cells
-supportive function in enamel production
What is the cell type and the function of the dental sac?
collagen fibers around enamel organs
-differentiate into cementum, PDL, and bone
What is the cell type and the function of the dental papillae?
cells nearest IEE have basement membrane separation
-outer cells differentiate into odontoblasts, whereas inner cells differentiate into pulp tissue
What tissues are in the enamel organ?
-OEE
-stellate reticulum
-stratum intermedium
-IEE
What is the cervical loop?
junction of the outer and inner enamel epithelia
-site of CEJ in adults
What is hertwig’s root sheath?
fusion of apical extension of the outer and inner enamel epithelium
What determines the outline of the root dentin and the number of roots a tooth will have?
hertwigs root sheath
when is hertwig’s root sheath removed?
before the cementum is laid down
Where does enamel stop forming?
at the end of the enamel organ
What causes the tooth to move occulusally?
the continued formation of dentin after enamel stops
What divides the pupal tissue and creates multiple roots
the epithelial modification of Hertwigs root sheath
When is the root formation completed?
1-4 years after the tooth erupts
What is the appositional stage of tooth development?
the time where the enamel and dentin are growing against each other and cause the proper formation
What does the stratum intermedium create?
alkaline phosphatse
What does the inner enamel epithelium become?
ameloblasts -> enamel
What do the peripheral cells of the dental papillae become?
odontoblasts -> dentin
What is mantle dentin?
the first formed dentin.
-30-50 um thick
-has type I and III collagen
How is the collagen in the matrix of the mantle dentin aligned?
perpendicular to the DEJ
What is the shape of ameloblasts actively secreting enamel?
tall columnar
What is the shape of ameloblasts that are inactive?
short columnar or cuboidal cells
What layers are combined to form the primary cuticle (Nasmyth’s membrane) ?
-reduce ameloblasts
-outer enamel epithelium
-stellate reticulum
-stratum intermedium
What is adontia?
refers to the total lack of tooth development
What is hypodontia?
denotes the lack of development of one or more teeth
What is oligdontia?
indicates the lack of formation of six or more teeth
What is hyperdontia?
development of an increased number of teeth (supernumerary)
When does the defect occur when there are supernumerary teeth?
during the initiation stage
What is a mesoden?
the most common manifestation of supernumerary tooth formation
-an extra tooth formed right at the midline between the central incisors
What is an odontoma?
small fragments of tooth structure consisting of dentin, enamel, cementum, or any combination
When does an odontoma begin formation?
during the initiation stage
What is a complex odontoma?
conglomerate mass of enamel and dentin that bears no anatomical resemblance to a tooth
What is a compound odontoma?
comprised of multiple, small tooth like structures
What is the treatment for complex odontoma?
complete removal
-is locally invasive and will continue growing
-can result in a thinning mandible that is more likely to fracture
What is taurodontism?
an enlargement of the body and pulp chamber of multirooted teeth with apical displacement of the bifurcation
What is an example of taurodontism?
exceptionally long root truck with very short roots
What is dilaceration?
abnormal angulation or bend in the root
What is gemination?
defect that originates in the cap stage of development that results in large single rooted tooth with one pulp cavity
-twinning in crown area
What is fusion?
when two teeth start growing together
-two roots with only one apparent crown
What is the difference between gemination and fusion?
gemination: tooth count is normal when the double tooth is counted as one
fusion: tooth count reveals a missing tooth when the double tooth is counted as one
What is concrescence?
defect that occurs during apposition and maturation that result in the union of root structures of two or more teeth by cementum
What is tubercle formation?
defect that occurs during the cap stage of development
-results in an extra cusp due to effects on enamel organ
What is a dentigerous/ follicular cyst?
cyst that is attached to the CEJ
-20% of all jaw cysts
-originates by separation of dental follicle from the crown of an unerupted tooth
What type of cell do keratocystic odontogenic tumors arise from?
cell rests of the dental lamina
Where are 65% of keratocystic odontogenic tumors?
in the mandible
What type of cysts are keratocystic odontogenic tumors?
bone expanding cysts
What is the treatment of keratocystic odontogenic tumors ?
surgical removal
-recurrance rate of 30%
What do the walls of the keratocystic odontogenic tumors look like?
stratified squamous epithelium with parakeratinosis at the luminal surface
-lumen typically contains keratin
What is an ameloblastoma?
most common type of neoplastic lesion arising from odontoblastic epithelium
What are ameloblastomas considered?
locally invasive tumors
How do ameloblastomas appear on radiographs?
multilocular “soap bubble”
-radioresistant
