Dentin & Pulp Flashcards
What structures make the dentinal structure?
Dentinal tubules
Odontoblast processes
What are canaliculi and where are they located?
They connect adjacent tubules
Dentinal tubules
Dentinal Structural Features
What are the Incremental Lines of von Eber?
- Daily incremental growth lines.
- Distance is dentin deposited over a period of 24 hrs
- Similar to cross striations in enamel
Dentinal Structural Features
What are the Contour lines of Owen?
- Wider thickened incremental lines.
- Represent metabolic disturbance occurring during apposition.
- Similar to stria of Retzius in enamel
Dentinal Structural Features
What is the neonatal line?
- Accentuated contour line of Owen.
- Represent sudden physiologic change occurring during parturition
What are the 2 classifications of tubular dentin?
Peritubular or intratubular dentin
Intertubular dentin
Classification of Dentin:
What is Peritubular or intratubular dentin?
Lines the wall of the dentinal tubule
Highly mineralized dentin
Classification of Dentin:
What is Intertubular dentin?
- All dentin located between dentinal tubules.
- Majority of dentin.
- Less mineralized than intratubular dentin.
What are the 3 classifications of surface dentin?
Mantle dentin
Circumpulpal dentin
Predentin
Classification of Dentin:
What is Mantle dentin?
First-formed layer of crown and root dentin.
Nearest to DEJ/DCJ.
Collagen fibers larger and oriented perpendicular to DEJ.
Classification of Dentin:
What is Circumpulpal dentin?
The bulk of dentin underlying the mantle dentin.
Collagen fibers smaller in diameter and more randomly oriented.
Classification of Dentin:
What is predentin?
A layer of newly secreted organic matrix.
Unmineralized
What are the 3 classifications of developing dentin?
Primary, Secondary and Tertiary dentin
Classification of Dentin:
What is primary dentin?
Dentin formed prior to and during tooth eruption.
Regular S-shaped pattern of tubules.
Classification of Dentin:
What is secondary dentin?
- Dentin formed after the tooth is in occlusion.
- Junction between 1° & 2° dentin is characterized by a sharp change in direction of dentinal tubule.
- Forms more slowly than primary dentin.
Classification of Dentin:
What is tertiary dentin?
Localized, rapid formation of dentin.
Deposited on pulpal surface under secondary dentin only at sites corresponding to areas of stimulation.
Response to some trauma which exposes dentinal tubules to oral environment.
Seals off tubules from pulp.
Sparse and irregular dentinal tubules.
What are the 2 classifications of Tertiary dentin?
Reactive dentin
Reparative dentin
What is reactive dentin?
Tertiary dentin class
Formed by preexisting or original odontoblasts.
Newly formed tubules continuous with those of secondary dentin
What is reparative dentin?
Tertiary dentin class
Formed by newly differentiated odontoblasts.
Preexisting dentinal tubules discontinuous
What is dead tract dentin?
- Tract of dentin containing empty tubules.
- Forms when odontoblasts either killed or injured and processes retracted, leaves empty dentinal tubules.
- Acute response to some trauma.
- Dentinal tubules are filled with air during histological processing
Appears black under microscope
What is sclerotic dentin?
Area of dentin containing dentinal tubules completely occluded with minerals.
Slower response to chronic trauma.
Appears transparent under microscope
Explain a bit about general dentin sensitivity
- Mechanical, thermal, and tactile stimuli are perceived as pain
- Bradykinin and histamines do NOT produce pain in dentin
What are the 3 theories of Dentin sensitivty?
- Nerves in dentin
- Odontoblast as receptor
- Hydrodynamic
What is pulp?
Only soft tissue of the tooth
Specialized loose connective tissue
Derived from neural crest cells
Functions: SeñoR. Do Not Fck
- Sensation, Reparative, Defense, Nutrition and Formation
