OB D10 : Pulp Flashcards
Describe dental pulp.
- connective tissue
- Essentially a matured dental papilla
what is dentine in relation to the pulp?
Dentine is the calcified tissue of the pulp
What are the pulp functions?
- Dentine formation
- Defence and repair
- Sensory
What is the pulp always producing?
secondary dentine
what else can the pulp produce?
reparative and reactionary tertiary dentine
What makes up the gross anatomy of the pulp?
- Pulp horns
- coronal pulp chamber
- radicular pulp
- apical foramen
what do pulp horns mimic?
cusps
what is important to remember when drilling young teeth?
Dont drill far before. you hit pulp chamber as pulp is big and equally its very easy for caries to get there
what is the aim of a root canal?
to get rid of this space and leave no infected tissue
what is not desirable?
apical delta
what can be a source of root canal failure?
Lateral canals are hard to see sometimes not visible til X-rays are taken after a root canal – cannot get instrument in there
what are the similarities between pulp and connective tissue?
- Cells ‐ mainly fibroblasts. -collagen matrix
- ground substance
- blood vessel and nerves
- 75% water 25% organic
what are the differences between pulp and connective tissue?
- Specialised cells (odontoblasts )
- Contained in a rigid chamber
- No fat cells
- No oxytalin fibres (?)
- No mast cells
- Blood vessels ‐ wide lumen, narrow wall
- Densely innervated
what does inflammation cause pain in the pulp?
pulp volume cannot increase therefore inflammation cause pressure
Describe layers of the pulp in cross section from outside to inside.
- Odontoblast layer
- Cell-free zone of weil
- Cell rich zone
- Pulp core
Describe the odontoblast layer.
- Odontoblasts: columnar cells (50μm long in crown) process in dentine -Appears pseudostratified (appears layered but has one layer - organelles reflect activity - junctional complexes ‐ barrier
Name all the pulpal cells.
- odontoblasts
- fibroblasts
- undifferentiated ectomesenchymal cells
- defence cells
What cell is most numerous in the cell rich zone?
fibroblasts
Describe undifferentiated ectomesenchymal cells.
- retain embryonic potential
- Decrease with age
- can form fibroblast or odontoblast
Name the 2 defence cells in pulp.
- Macrophages
- Lymphocytes
What makes up the fibres of the pulp?
-Collagen (34% of pulp proteins)
-Of this collagen:
type 1- 56%
type III - 41%
also type V and VI
-no oxytalin fibres (elastic)
Describe the the blood supply in pulp.
- Rich blood supply Contains - Terminate in rich sub‐ odontoblastic capillary plexus - Venules have no valves - Thin walled vessels - High perfusion rate
where must the blood that comes into the pulp go?
come back out as cannot pool in the pulp
What does dentinal fluid contain?
- proteins
- glycoprotein
- polysaccarides
where does fluid flow out?
outwards in opened tubules
what is the intrapulpal pressure?
10mmHg
what is the dentinal fluid flow velocity?
1-2 micrometers per second
what fluid flow changes pulpal pressure?
- Inflammation
- Vasoconstrictors
what does vasoconstrictor in LA do and why could this be a problem?
vasoconstrictors in LA reduce the blood flow in the pulp and the rate of fluid flow out of the tubules – could be bad as outward fluid flow is protective
Describe the pulpal innervation.
- rich innervation
- mainly sensory ‐ i.e. afferent
- also efferent post‐ganglionic sympathetic
- likely no parasympathetics
what percentage if nerves are non-myelinated in the pulp?
70-80%
what makes up the rest of myelinated fibres?
– 90% Ad (1‐6 m diameter)
– 10% are AB (6‐12 m diameter)
what do nerves get towards the end?
more narrow
what is the plexus of raschkow?
classically in the cell free zone
where is the marginal plexus?
around odontoblasts
