6 - Tooth germ - morphological stages in the development of the dental papilla and the dental sac. Functions of the elements of the tooth germ. Flashcards
1
Q
Dental Papilla
A
Dental papilla is the 2nd element of dental germ below inner epithelium of enamel organ
It has mesodermal + ectomesenchymal origin
It is separated from enamel organ by a basement membrane
2
Q
Development of Dental papilla
A
- Cells appear as undifferentiated ectomesenchymal cells
- Blood vessels appear early in papilla, initially in central region w/nerve fibres ⇢ nutrition
- Smaller capillaries form in periphery of papilla ⇢ nutrition for odontoblasts + ameloblasts
3
Q
Functions of Dental papilla
A
- Ectomesenchyme forms preodontoblasts in early bell stage
- Also forms odontoblasts in late bell stage
- Papilla cells ⇢ further enamel bud formation into cap + bell stage
- Dental papilla dives rise to dentin + dental pulp
3
Q
Functions of Dental papilla
A
- Ectomesenchyme forms preodontoblasts in early bell stage
- Also forms odontoblasts in late bell stage
- Papilla cells ⇢ further enamel bud formation into cap + bell stage
- Dental papilla dives rise to dentin + dental pulp
4
Q
Dental sac/follicle
A
- Ectomesenchymal + mesodermal/mesenchymal origin
- Has many more collagen fibrils that occupy extracellular spaces between follicular fibriblasts compared to papilla
- gives rise to 3 important elements:
- Cementoblasts ⇢ Cementum
- Osteoblasts ⇢ Alveolar bone
- Fibroblasts ⇢ Periodontal ligaments ⇢ connect teeth to alveolar bone
5
Q
Role of dental sac in development of tooth structure
A
- Brings nutrition to enamel organ + dental papilla
- It limits their growth impulses
- Forms cement, periodontium + alveolar bone
6
Q
Functions of tooth germ elements in formation of teeth
A
Enamel organ ⇢ Forms enamel + furthered dental papilla + dental follicle
Dental papilla ⇢ Forms dentin + dental pulp
Dental Sac ⇢ Forms cement, periodontium + alveolar bone
