Dentin! Flashcards
Process of making dentin?
- Collagenous matrix from odontoblasts
2. Maturation through matrix
What is the origin of dentin?
Outer cells of dental papilla (ectomesechyme)
Dentin anatomy?
70% inorganic-by hydroxyapatite
20% organic-collagen
10% water
How is dentin formed?
- Continues as long as tooth is vital
- Can be stimulated environmentally
Ex: cutting dentin away at the dej, or heavy handed scaling
Function of dentin?
Shock absorber for the tooth
Color of dentin?
Basically yellow
Foramina and lateral canals in dentin?
Found in the root.
-apical foramen transmits nervous and circulatory elements
Dej in dentin?
Scalloped union with enamel
Increases surface area which increases strength of the union
3 different types of dentin
- Peritubular
- Intertubular
- Circumpupal
Components of mature dentin?
- Dentin tubules
- travel from pulp to dej
- contain h2o, odontoblastic process and afferent neuron - Dentinal permeability-tubules/mm2
- Odontoblastic processes is a cellular extension
- Dentinal fluid
Peritubular dentin
Creates the walls of dentin tubules
Intertubular dentin
Dentin between tubules
Also the least mineralized
Circumpulpal dentin
Surrounds the pulp chamber
Most deep
Most mineralized
3 dentin types based on formation
- Primary
- Secondary
- Tertiary
Primary dentin formation
Formed before closing of the apical foramen
Secondary formation of dentin
Deposited at the pulpit periphery after root is completed.
This is the process of odontoblasts laying dentin down which makes pulp look smaller
Tertiary formation of dentin
Formed in response to noxious stimuli
Ex. When someone cuts into dentin or stimulates odontoblasts. Can also include dental caries
3 types of dentin based on mineralization
- Globular mineralization
- Secondary mineralization
- Inter globular dentin
Globular mineralization
Fusion of primary and secondary formation to completion
Secondary mineralization
Occurs after primary formation is done. Some areas fuse with primary formation but not all complete
Interglobular dentin
Less calcified and less mineralize. More present closer to the DEJ
Some microscopic features of dentin
- Imbrication lines of vonEbner-daily difference in apposition/maturation
- Contour lines of Owen-from trauma
- Neonatal line-most obvious; trauma of birth
- Granular layer of tomes-just deep to cej or CDJ-less calcified
