L58. Dental Development Flashcards
Name the 3 layers from which an embryo develops.
Ectoderm
Mesoderm
Endoderm
What does the ectoderm do?
Forms the exoskeleton
What does the mesoderm do?
Develops into organs
What does the endoderm do?
Forms the inner lining of organs.
Where does tooth enamel derive from?
Ectoderm
Where do all tooth structures excluding enamel derive from?
Ectomesenchyme.
What is the ectomesenchyme?
Part of the primitive nervous system’s neural crest.
What do teeth develop from?
Tooth germs
What forms between the ectoderm and the neural tube?
Neural crest tissue/ectomesenchyme
What is the embryonic mouth called at 6 weeks?
Stomodaeum
When does the dental lamina form?
7-8 weeks
When is the bud stage??
8-10 weeks
When is the cap stage?
11 weeks
What happens in the cap stage?
enamel forms a cap over the papilla
When does the bell stage happen?
14 weeks
What happens in the bell stage?
There is a defined tooth shape
When does the permanent tooth germ develop?
16 weeks
When is the late bell stage?
18 weeks
What happens in the late bell stage?
dentine and enamel formation
What is unmineralised dentine called?
Predentine
What is mineralised dentine called?
Hydroxyapatite
Describe the 2 stages of enamel formation.
- Partially mineralised protein matrix is deposited
2. Organic part is removed and mineralisation is completed (maturation).
Name the 3 stages of amelogenesis.
- Differentiation
- Secretion
- Maturation.
What happens in the differentiation stage of amelogenesis?
ameloblasts elongate, becoming columnar.
The nucleus migrates to the basal end of the cell.
What happens in the secretion stage of amelogenesis?
Cells become secretory cells. They synthesis and secrete enamel matrix proteins.
What is another name for enamel matrix proteins?
amelogenins
What happens in the maturation stage of amelogenesis?
Most matrix proteins are removed.
Mineral content is increased to 95%.
Describe the process of root formation.
The enamel organ maps out the shape of the crown.
External and internal enamel epithelium meet at the cervical loop.
Apical growth of the cervical loop defines the root shape called Hertwig’s epithelial root sheath, made of 2 layers.
What surrounds the dental papilla?
Enamel organ
What surrounds the enamel organ?
Dental follicle.
What does supernumerary mean?
Extra teeth
What does fusion mean?
2 teeth fused together
What does hypodontia mean?
missing/underdeveloped teeth
What does gemination mean?
2 teeth develop from 1
What does dentinogenesis imperfecta mean?
dentine dysplasia
