Dentine Flashcards
Composition of Dentine
inorganic 70%
organic 20%
water 10%
What type of filling is composite
hydrophobic
What cells form dentinogenesis
odontoblasts
Where do odontoblasts differentiate from?
ectomesenchyme (dental papilla)
Where are spherical zones of hydroyapaite-calcospherites formed?
dentine matrix
What is the 1st layer of mineralised dentine and the remaining?
1st - mantle dentine
remaining - circumpulpal
What is unmineralised dentine called
predentin
What are circular areas of mineralisation called
calcospherites
What is interlobular dentine
unmineralised dentine
failure of calcospherites to fuse
What is dentine
mineralised tissue forming BULK of tooth
underlies enamel in crown
covered by cementum in root area
pale yellow colour
What is the main inorganic component of dentine
hydroxyapatite
What is the main organic component of dentine
collagen fibres embedded in amorphous ground substance
What process occurs within the dental tubules
odontoblast process
What is secondary dentine
dentine continuously forming
laid down at plural end of primary dentine
What makes the pulp chamber reduce in size with age?
secondary dentine
Where is peritubular dentine found?
In each dentinal tubule surrounding the odontoblast process
When are incremental lines visible?
contour lines of Owen
when dentinogenesis is disrupted
Peritubular dentine tends to increase with age what does this reduce?
diameter of the dentinal tubules
What are the two outcomes of tertiary dentine?
Reactionary - mild irritant
- odontoblasts survive
Reparative - strong irritant
- odontoblasts die
where does the dentine tubules run from
plural surface - enamel-dentine and cementum dentine junctions
What are the curved, sigmoid course called what the dentine tubules follow
primary curvatures
Where is interlobular dentine found
dentine between the tubules
What is it called when tubules change direction
secondary curvatures
What is more mineralised peritubular or intertubular dentine
Peritubular dentine
Mineralisation is controlled by odontoblasts by controlling which
controlling influx of Ca2+ ions
controlling secretion + metabolism of matrix proteins
Mineralisation is under principal control of the
DPP
dentin phosphoprotein
