Dentin and Pulp Flashcards
Describe dentin
less hard than enamel, smaller crystals
Makes up bulk of tooth***
Yellow color reflected through enamel
More radiolucent than enamel, more radiopaque than pulp
Attrition
*more rapid when dentin is exposed
How does apposition of dentin matrix occur?
predentin produces initial dentin matrix, laid down by odontoblasts (outer cells of dental papilla)
apposition of dentin occurs during life of tooth
Mineralization/maturation of predentin occurs in how many stages?
2; primary and secondary
Primary maturation
hydroxyapatite form globules in collagen fibers of the dentin, allows for expansion and fusion of crystals
Secondary maturation
new areas of mineralization as globes form in partially mineralized predentin, new crystals regularly layered allow them to expand, but fuse incompletely
Globular dentin
complete crystalline fusion in both phases, light rounded areas
Interglobular dentin
incomplete fusion, only mineralized in primary phase, slightly less mineralized, dark arc like areas
Where is interglobular dentin found?
coronal dentin near DEJ
when in root, known as Tome’s Granular Layer*
What do dentinal tubules contain?
odontoblastic process, fluid, afferent nerve axon
provides nutrition since dentin is avascular
Primary curvature of dentinal tubules
overall tubule course over time, resembles S shaped curve
Secondary curvature of dentinal tubules
smaller, delicate curves noting daily changes of odontoblast direction during apposition
Peritubular dentin
halo effect, creates walls of tubules, highly mineralized
Intertubular dentin
between tubules, less mineralized than peritubular*
Mantle dentin
first predentin that forms and matures within tooth
Circumpulpal dentin
deep to mantel, around wall of pulp, makes up bulk of dentin*
Primary dentin
forms before completion of apical foramen
Secondary dentin
forms after completion of apical foramen, forms during life of tooth
*produces smear layer
Reparative/Tertiary/Reactive dentin
forms quickly in response to trauma or injury to exposed dentin
Sclerotic dentin
transparent form of tertiary/reactive dentin, associated with chronic caries, shiny areas
Hydrodynamic dentinal hypersensitivity theory
open dentinal tubules which have fluid moving around and irritating afferent nerve axon result in dentinal hypersensitivity
Imbrication lines of Von Ebner
growth like band rings due to appositional growth of dentin
Contour Line of Owen: Neonatal
number of adjoining parallel imbrication lines
Neonatal: occurring during trauma at birth, larger the trauma=longer the line
Tome’s Granular Layer
peripheral part of dentin under root cementum, increased levels of interglobular dentin, appears granular and less mineralized
