Tooth Development Flashcards
(27 cards)
What does enamel arise from?
oral ectoderm/dental lamina
What eventually forms the dentin and pulp?
the dental papilla
The dental follicle arises from ___________ and forms what part of an erupted tooth?
Comes from ectomesenchyme, forms the cementum, PDL, and alveolar bone
Which is the first tooth to begin formation?
Mandibular central incisor (around the end of week 5 in utero)
What three major components in the Cap stage make up the tooth germ?
1: enamel organ
2: dental papilla
3: dental follicle
The enamel knot marks what?
The beginning stages of each cusp
Inner enamel epithelium derives what?
Preameloblasts, then those become ameloblasts which deposit enamel.
Where are stellate reticulum cells found during tooth development, and what do they do?
These cells are found filling the majority of the enamel organ. They help expand the enamel organ and keep the germ nourished.
Where would you find stratum intermedium cells and what do they do?
These cells are inside the enamel organ, butted up against the inner enamel epithelium. They support enamel mineralization.
When do enamel knots form?
End of cap stage/beginning of early bell stage
What does the basement membrane form?
It forms the odontoblasts
What activates the basement membrane to differentiate into odontoblasts?
The IEE differentiating into preameloblasts at the enamel knot signal to basement membrane to change.
What tells polarized preameloblasts to become active ameloblasts?
The formation of predentin/dentin being deposited.
During the bud stage, what signaling molecules are used by epithelial cells to differentiate the ectomesenchyme?
SHH, BMP-4, Fgf-8, Lef-1
What makes the tooth bud?
Epithelial cells proliferating at a high rate. (they also secrete SHH to differentiate ectomesenchyme)
Which side of the tooth germ does the successional dental lamina form?
Lingual side
What is reciprocal induction?
The transfer of control from the IEE to dental papilla, and then back to IEE again.
List the major stages of tooth development, and the general timeline.
- Lamina stage
- Bud stage
- Cap stage
- Early bell stage
- Late bell stage
- Apposition stage
- Maturation stage
- Eruption stage
In what stage does enamel deposition begin?
Apposition stage
What forms enamel prisms?
formed by Tomes processes of late secretory ameloblasts
What forms prismless enamel?
Formed by early secretory ameloblasts
What is Hertwig’s epithelial root sheath?
An extension of the inner and outer enamel epithelium, and is the root of the epithelial diaphragm (also where CEJ forms)
What is passive eruption cementum?
Extra cementum formed on the root apex due to attrition of the crown.
When does Reduced Enamel Epithelium form?
After the enamel is fully matured
