Odontogenesis Flashcards
The development of the tooth involves interplay between what 2 principle tissues types?
- Ondontogenic epithelium
- Ectomesenchyme (derived from neural crest cells)
What are the 3 primitive tooth germs?
- Enamel organ/odontogenic epithelium
- Dental Follicle
- Dental Papilla
Of the three primitive tooth germ parts (enamel organ, dental follicle, and dental papilla) which two are derived from ectomesenchyme?
- Dental follicle
- Dental papilla
The enamel organ is derived from what tissue?
It is odontogenic epithelium derived from the dental lamina
What does the dental papilla form?
tooth pulp and dentin
What does the dental follicle form?
PDL and associated structures
What are the 4 stages of of tooth development?
- Bud
- Cap
- Bell
- Crown
Refers to the shape of the epithelial tooth germ
The bud stage initiates the extension of the oral epithelium into the sub epithelial tissues form what structure?
Dental Lamina
The odontogenic epithelium of the dental lamina induces the subjacent ectomesenchyme to form what two structures in the cap stage?
Dental papilla
Dental follicle
What two cell layers exhibit specific histological features that are commonly recognized as characteristic of odontogenic epithelium?
- Ameloblasts
- stellate reticulum
The enamel organ is composed of what 4 histologically distinct layers of cells?
- ameloblasts
- stratum intermedium
- stellate reticulum
- outer enamel epithelium
Ameloblasts + Stratum intermedium = inner enamel epithelium
What is reciprocal induction in regards to tooth formation?
Ameloblasts signal odontoblasts to produce dentin followed by dentinal matrix signaling ameloblasts to produce enamel
Dentin formation precedes enamel formation. Deposition of the two matrices gradually forces the palisading ondontoblsts and ameloblasts apart. During this time the dental lamina fragments into islands of epithelium referred to as the rests of serres
Why is the enamel matrix absent from mature teeth in histological sections?
It is composed of 95% mineral which is removed during the sectional processing (decalcification)
The purpose of the bi-layered tube of epithelium called ________________ that surrounds the tooth root is the formation of dentin in the root of a tooth by causing the differentiation of odontoblasts from the dental papilla.
Hertwigs epithelial root sheath
What are the rests of Malassez?
As tooth development progresses the epithelium of HERS partially disintegrates resulting in isolated islands of odontogenic epithelium that persist within the PDL.
