Tooth Development: Putting it all together Flashcards
What teeth would you expect to see in an 8 yr old?
Permanent first molars and incisors; primary canines and molars
What type of radiographs would be needed for an 8 yr old new patient that is disastisfied with teeth?
Posterior bitewing w panoramic
Do the crowns or roots develop first?
Crown
What are the 5 stages of crown formation?
Initiation Stage Bud Stage Cap Bell Enamel, dentin, and pulp formation
corresponds to the dental arches and gives rise to dental lamina and vestibular lamina
Primary epithelial band
_____ is expressed in the epithelium where the tooth bud would form
Shh
_____is expressed in the mesenchyme where the tooth bud would form
Pax9
_____ formation is an epithelial thickening important in the initiation of tooth development
Placode
In initiation of tooth development, does the mesenchyme grow into the epithelia or does the epithelia grow into mesenchyme?
Epithelia outgrowth into mesenchyme
Initial odontogenic potential lies in the epithelia or mesenchyme?
Epithelia
The ________ induces the oral ectoderm to become to the dental lamina
Neural crest mesenchyme
____ stage of tooth development:
- epithelial cells show no major changes
- Shh, Lef-1, and Eda-Edar involved in placode formation
- Mesenchyme beneath starts to condense by the factors secreted by the epithelium
- Cross-talk between the epithelium and the mesenchyme
- Odontogenic potential in the epithelium
Bud stage
____ stage of tooth development:
- epithelium proliferates; mesenchyme continue to condense
- tooth germs present
Cap Stage
Bud to cap stage transition is regulated by what 2 things?
Signaling molecules and transcription factors
_____ is a tooth germ in the cap stage forming the enamel of the tooth
Enamel organ
_____ is a tooth germ in the cap stage forming the denitn and pulp
Dental papilla
Supporting structures (cementum/ periodontium/ alveolar bone proper) all come from _______
Dental follicle/sac
____ is a key signaling centers that consists of non-dividing cells determines cusp formation;
Enamel knot
Cells in enamel organ synthesize ______ in to the ECM; hydrophilic and pull water in to enamel organ
Glycosaminoglycans
Enamel organ epithelial are separated into what 2 categories?
Inner and Outer enamel eptihelium
____ stage of tooth development:
- under surface of the epithelium deepens and resemble a bell
- stratum intermedium formation
- crown attains full size and shape
Bell stage
The junction of the inner enamel epithelium and outer enamel epithelium is called the _____: plays important roll in determining roots of teeth
Cervical loop
____ stage of tooth development: (late)
- dental lamina breaks and separates the tooth from oral epithelium
- IEE completes folding forming the future crown pattern
- Folding is due to differential rates of mitotic division in IEE
- Under influence of IEE mesenchymal cells differentiate into odontoblasts that makes dentin
- IEE differentiate into ameloblasts and make enamel
- Site at which IEE differentiates determines future cusp formation
Late bell stage
Does dentin or enamel form first?
Dentin
Dentin forms from the ______
mesenchmye
Permanent dentition forms _____ to the deciduous dentition
Lingual
IEE and OEE from the cervical loop proliferate downward to form double layered structure called ______
Hertwig’s epithelial root sheath
_____ are formed by:
- Fragmentation of Hertwig’s epithelial root sheath
- Differentiation of cementoblasts from Hertwig’s epithelial root sheath or dental follicle cells
- can be cellular or acellular
Cementum
Remnants of Hertwig’s epithelial root sheath are called _____
Epithelial rests of Malassez
Enamel formation is called ____
Amelogenesis
What are the 7 stages of amelogenesis?
- Morphogenic Stage
- Histodifferentitation Stage
- Initial secretory stage (no Tome’s process)
- Secretory stage (Tome’s process)
- Ruffle ended ameloblast of the maturative stage
- Smooth ended ameloblast of the maturative stage
- Protective stage
___ stage of ameloblasts:
- intense synthetic and secretory activity
- forms enamel rod and inter-rod
- secrete granules on the newly formed mantle dentin
- proteins
- proteases
Secretory stage
What are the 3 secretory proteins secreted in secretory stage of ameloblasts?
Amelogenin
Ameloblastin
Enamelin
What are the 2 secretory proteases secreted in secretory stage of ameloblasts?
Enamelysin (MMP20)
Kallkrien
____ dentin: first layer of dentin formed by the newly differentiated odontoblasts, hypomineralized, and only in the crown of the tooth
Mantle dentin
____ dentin: formed during tooth development (4um/day)
Primary dentin
____ dentin: formed after tooth eruption
Secondary dentin
____ dentin: produced in response to injury to protect the pulp
Tertiary dentin
