Dentine Microstructure Flashcards
Dentinal tubules morphology:
Where do dentinal tubules run from and to
From the pulpal surface to the ADJ interface
Dentinal tubules morphology:
What is dentine location between tubules called
Intertubular dentine
Dentinal tubules morphology:
Where is peritubular dentine deposited with maturation
On the walls of the dentine tubules, narrowing their lumens
Dentinal tubules morphology:
Describe primary curvatures
- Describe the S shaped path dentine tubules follow
- As tubules progress down the root, the curvature is much less pronounced
Dentinal tubules morphology:
Describe secondary curvatures
Small, regular wave-like deviations in the path of dentine tubules
Where is the branching of dentinal tubules most noticable
Near the ADJ, immediately under the enamel in the tooth crown
Dentinal tubules morphology:
In the root, the terminal part of tubules branch and the branches loop, what may this looping be responsible for?
The apperance of the granular layer of Tomes beneath the CEJ in the root
Dentinal tubules regional variation:
Where may dentinal tubules be wider
Wider at the pulpal end
Dentinal tubules regional variation:
What is the relation between peritubular dentine and following a tubual from its pulpal end to its periphal end
More peritubual dentine in found on its walls, gradually decreasing the diameter of the tubual’s lumen
Dentinal tubules regional variation:
Where are dentinal tubules more widely seperated and tightly packed
Why is this the case
- More widely seperated at their peripheries near the ADJ and more tightly packed near the pulp
- This is because the outer surface area of dentine at the ADJ is larger than the inner pulpal surface area whilst the number of tubules at the 2 positions remains the same
Dentinal tubules regional variation:
Where do odontoblasts migrate and where do they occupy
- Migrate inwards
- Occupy a small surface area (become more crowded) as dentinogenesis progresses towards the pulp
Peritubular dentine:
What is the difference between peritubular dentine and intertubular dentine?
Peritubular dentine lacks a collagen fibrillar matrix
Peritubular dentine:
What does peritubular dentine consist of?
Consists of small crystals in a non-fibrillar matrix consisting of:
- Proteoglycans
- Glycoproteins
- Osteonectin
- Osteocalcin
- Bone sialoproteins
- Lipids
Peritubular dentine:
What is the mineral component of peritubular dentine mainly
Mainly carbonated apatite
Peritubular dentine:
In older teeth, where is peritubular dentine formation?
Usually found near the root apices
Peritubular dentine:
Describe the relation between peritubular dentine formation and intertubular dentine formation
- Formation occurs around the same time
- By the time primary dentine formation is complete, all peripheral tubules have a lining of peritubular dentine that extends from the ADJ to the mineralisation front
Peritubular dentine:
Where is dentine first formed
Near the ADJ
Peritubular dentine:
What percentage of peritubular dentine occupies the cross-sectional area in the dentine near the ADJ
66% (two thirds)
Peritubular dentine:
What percentage of peritubular dentine occupies the cross-sectional area near the predentine
3%
Dentinal tubules content:
What do dentinal tubules contain
- Long processes of odontoblasts
- There are responsible for the formation + maintenance of dentine
Dentinal tubules content:
Where are cell bodies of the odontoblasts found?
At the pulpal end of the tubules, lining the walls of the pulp
Dentinal tubules content:
What may also be found at the inner part of dentinal tubules
- Antigen-presenting cell processes from peripheral pulp
- Afferent sensory nerve axons
Dentinal tubules content:
What is the space around + beyond an odontoblast process thought to be filled with
What occurs if dentine is cut?
- Dentinal fluid
- Fluid is dicharged from tubules + the dentine surface remains wet
Dentinal tubules content:
Where do the odontoblast processes occupy when dentine is in the early stages of development?
Occupy the full width of the dentinal tubule
Dentinal tubules content:
What happes to the number of tubules occupied by odontoblasts seen as we move to outer dentine
The number of tubules occupied by odontoblasts decreases
Dentinal tubules content:
What happens when the odontoblast process reaches a predetermined length
The odontoblast process moves towards the pulp, along with the odontoblast cell body, leaving behind an empty tubule in which peritubular dentine has formed
