Dentine Flashcards
Dentine
-forms the bulk of the tooth
-sensitive tissue
- formed throughout the life
- large no. parallel tubules in a mineralized collagen matrix
- the tubules contain the processes of odontoblasts
Physical properties of dentine
fresh dentine is pale yellow
- stronger than cementum and bone but softer than enamel
-high compressive tensile & flexural strength
- permeable , depending on the patency & size of the tubules
Inorganic compositions
calcium hydroxyapatite poor in calcium and carbonate rich , much smaller than the enamel hydroxyapatite
where can u find the hydroxyapatite ?
on and between the collagen fibrils
Organic compositions
collagen type I
gla-proteins
dentine phospho-proteins
acidic proteins
lipid & growth factors
chemical composition -organic matrix
90% of the organic matrix is made of collagen type 1
Phosphoryn
most acidic protein known
- due to high calcium concentration -> mineralization
- main phosphoprotein in dentine
Proteoglycans
organic matrix
main proteoglycans are biglycan and decorin
- important role in collagen assembly / may have role in mineralization
which organic component has an important role in collagen assembly ?
proteoglycans
Gla proteins
organic compositions
alpha carboxyglutamate
low amount in dentine
bind strongly but reversibly to hydroxyapatite crystals
Growth factors are absorbed from ?
circulating tissue fluid
phospholipids may be involved in the formation and growth of ….
apatite crystals
dentine tubules they extend from which junctions ?
from the pulp surface to the amelo- dentinal and the cemento dentinal junctions
tubules follow a … course ?
curved sigmoid
Dentine tubules are circular in which section?
cross sections
intertubular dentine
dentine between tubules
the tubules are 2.5 micrometer at the …. and 1 microm at the ..
pulpal end .. enamel end
when does the denitne tubules become closer to each other?
odntoblast retreats inward .. occupying smaller area
contour lines of owen?
secondary curvatures .. if they coincide (occur at the same time ) in adjacent tubules
intratubular dentine ?
lacks collagen matrix
The inorganic material in the peritubular dentine is ?
carbonated apatite , different crystalline than the intratubular dentine
what are the contents of the dentinal tubules ?
odontoblastic processes
afferent nerve terminals
antigen presenting cells processes
extracellular dentinal fluid
