Tooth Development ( Odontogenesis )
The Development Of The Tooth
Involves Many Complex Biologic Processes, Including
1- Ectoderm - Oral Epithelial (Stratified Squamous)
2- Ecto-mesenchymal (mesoderm C.T +Neural Crest) .
From This Interaction
1- 20 Deciduous - Labial to the dental lamina
2- 32 Permanent Teeth Develop. lingual to the dental lamina
The Fundamental Developmental Process Is Similar For All Teeth.
DEVELOPMENTAL STAGES
1- Initiation stage (dental lamina ):
It is formed by proliferation of the basal cell layer of the oral epithelium in the underlying
mesenchyme forming a band called tooth band or dental lamina .– Germal Layer - On The U Future
Jaws
2- ( Bud stage ) – initiation stage :
This stages starts at the beginning of eight week of prenatal development.
It involves extensive proliferation of the dental lamina into buds.
In each future jaw, ten oval buds start to penetrate into the surrounding ectomesenchyme .
that will later form the primary teeth.
3- Cap Stage ( Proliferation stage )
This stage starts between the ninth and tenth week of prenatal development.
During this stage, proliferation of cells continues, but in unequal manner in different parts of the
tooth bud, resulting in the formation of a three-dimensional cap shape overlying the
ectomesenchyme.
4- early-bell Stage (histo&morpho-differentiation)
The enamel organ assumes a bell shape due to invagination of enamel organ which becomes deeper
and called as early bell stage.
Once the first layer of dentin , it becomes late bell stage.
In this stage, the crown of the tooth gets its final shape (morpho-differentiation) .
the cells that form the hard tissues of the crown the ameloblasts that form the enamel )
( the odontoblasts that form dentin and pulp) acquire histo-differentiation.
