Odnotogenesis Flashcards
Two types of tissue
Oral epithelium (ectoderm) Ectomesenchyme (mesoderm)
The first development in development of the face is
Disintegration of the buccopharyngeal membrane
Oral epithelium develops into
Dental Lamina
Of odontogenesis begins
The 6th week of gestation
Primary teeth form …… and permanent teeth form ……
4th month in utero
At birth
What type of molecular interactions govern tooth development?
Intricate molecular interactions based on epithelial mesenchymal interactions
What signifies the start of odontogenesis?
The appearance of basal lamina
How is the primary epithelial band formed?
When horseshoe shaped epithelial cells (dental lamina) become surrounded by ectomesenchyme (NCC) and separated by basal lamina in the mand and max
Adonia is associated with
Ectodermal dysplasia
Most common problem in hyperdontia
Extra tooth in middle of max central incisors (mesioden)
Stages of tooth development from beginning
Stomodeum, oral epithelium, dental lamina, BUD, CAP, BELL
When does the bud stage begin?
After dental lamina incursion into the ectomesenchyme
Primary teeth are considered
Placode said into the ectomesenchyme in the future sites of deciduous teeth
Abnormalities during bud stage
Microdontia (max lat incisors and 3rd molars) and macrodontia (hemifacial hypertrophy)
At what stage is the tooth a 3 layered enamel organ?
Cap (OEE, SR, IEE)
What constitutes a tooth germ?
Enamel organ, dental papilla (ectomesenchyme more condensed), dental follicle (ectomesenchyme)
What is dental papilla?
Condensation of ectomesenchyme located next to enamel organ but separated by basement membrane
Peripheral cells in dental papilla differentiate into what?
Odontoblasts secrete dentin
How is the dental follicle different than the dental papilla?
Less cellular, more fibrous (collagen)
What do dental follicle cells do?
Inner - near enamel, become cementocytes
Outer - form PDL (periodontal ligament) and attribute to bone formation
5 layers in the cap stage?
Dental lamina, enamel organ, dental papilla, dental follicle, succedaneous dental lamina
When do accessional teeth form?
5th month of gestation
Abnormalities in cap
Dens in dente, fusion (less teeth), germination (correct teeth)
What happens in bell stage?
Morphodifferentiation (shape)
Histodifferentiation (amelo/odontoblasts)
Stellate reticulum
Center of enamel organ
Draws water to transport nutrients and calcium
Stellate intermediate
Assists in producing enamel by transferring phosphates from blood vessel
IEE
Inner enamel epithelia - forms ameloblasts
In the bell stage, the basal lamina becomes
the DEJ between the IEE and the dental papilla
OEE
Outer enamel epithelium - work with IEE to form the cervical loop
What is the cervical loop?
Where IEE and OEE meet. Also Hertwigs epithelial root sheath = development of the root
Two important events in bell stage?
Dental lamina disintegrates - separates developing tooth from oral epithlium
The crown pattern and cusps develop due to folding of the IEE
What a epithelial pearls?
Clusters of epithelial cells/fragmentation of the dental lamina that can be phagocytosed or form into cysts
Layer of skin for the face
Ectoderm
