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endo lecture 1

Terms in this set (70)

What are some effects of irritants and restorative procedures on the pulp?
1: affects pulp through dentinal tubules
2: can produce damage directly (pulp exposure)
3: can generate heat that affects pulp
What is Endodontics?
Branch of dentistry concerned with the morphology, physiology and pathology of the human dental pulp and periradicular tissues

endo: inside
donto: teeth
Where is the dental pulp located?
in the center of the crown and root

pulp in crown: pulp chamber
pulp in root: root canal
what type of connective tissue is in the pulp?
loose connective tissue
what encloses dental pulp?
pulp is enclosed in hard walls made of dentin
T or F: dental pulp has poor collateral circulation
true
is the dental pulp a terminal end circulation organ?
yes, leaving it very susceptible to injury
what would the shape of the pulp be if was removed from the tooth?
when removed intact, the pulp is a firm tissue that maintains its shape
dental pulp is connective tissue that is held together by what substance?
ground substance
the structure of pulp is reinforced by what?
collagen fibers
what is dental pulp derived from?
neural crest cells (ectomesenchyme) proliferate and condense to form the dental papilla from which the mature pulp derives
what does the enamel organ form?
enamel
what does the dental papilla form?
pulp and dentin
what does the dental sac form?
cementum and PDL (the peridontium)
what are the tooth developmental steps
step 1: papilla stimulates the inner enamel epithelium to differentiate into ameloblasts

step 2: ameloblasts in turn stimulate the papilla to differentiate into odontoblasts which begin to secrete predentin

step 3: the presence of predentin stimulates ameloblasts to begin secreting enamel
what is the epithelial diagram also known as?
cervical loop
what is the junction of IEE and OEE considered?
epithelial diaphragm
what is the future epithelial diaphragm?
CEJ
what structure proliferates to stimulate root formation?
Hertwig's epithelial root sheath (HERS) proliferates to form the root
when HERS ruptures and exposes dentin to connective tissue, how does this exposed dentin respond?
exposed dentin stimulates cementum deposition
what are cell rests of malasseze's?
epithelial remnants from HERS
what is the purpose of cell rests of malasseze's?
normally remain dormant, but can be activated by inflammation within the tissue
-when activated can proliferate providing lining of radicular cysts
what is a lateral canal?
an accessory communication between the pulp and the peiodontum
what are the 2 ways a lateral canal can form?
1: formed if HERS breaks down before dentin has had a chance to be laid down
2: can also form if blood vessels are not displaced during root formation
what is the apical foramen?
it is a narrow opening at the root end that acts as the main communication between the pulp and periodontum
what passes through the apical foramen?
nerves and blood vessels
where is the narrowest part of the apical foramen?
apical CDJ narrowest part of canal
can the apical foramen change with age?
yes, changes with age due to dentin and cementum deposition
what are the zones of the pulp?
odontoblastic zone, cell free zone, cell rich zone, pulp core
how is the odontoblastic zone arranged?
palisade arrangement
what is found in the odontoblastic zone?
odontoblasts and free nerve endings (pain receptors) penetrate this layer
how do odontoblasts communicate?
odontoblasts communicate with each other via tight, adhering, gap junctions
-if one is affected, many others are too
what is the cell free zone also known as?
zone of weil
what is present in the cell free zone?
many nerve fibers and contains capillaries
what can happen to this zone during rapid dentin formation?
this zone can diminish in size or temporarily disappear during rapid dentin formation, but overtime, can re-establish itself
what is contained in the cell rich zone?
contains many undifferentiated mesenchymal cells and fibroblasts
the cell rich zone serves as a reservoir for what?
destroyed odontoblasts
the cell rich zone is most frequently observed in where?
the coronal pulp
what is contained in the central zone/core of pulp?
core of loose connective tissue and contains larger nerves and blood vessels
what are the dental pulp components?
cells
intercellular components
nerves
blood vessels
lymphatics
what are the cells of the pulp?
odontoblasts
fibroblasts
undifferentiated mesenchymal cells
inflammatory cells
where is the cell body of the odontoblast located?
in odontoblastic layer
where are the odontoblastic processes of the odontoblast located?
they extend into dentinal tubules
what is the functions of odontoblasts?
1: synthesizing (cell body) predentin
2: secretory (odontoblastic processes) predentin
3: mineralizing predentin into dentin
what are the three structures seen in odontoblasts that are common in cells that produce a matrix?
1: Rough ER
2: golgi
3: mitochondria
what is the most abundant cell in pulp?
fibroblasts
what zone of the pulp are the fibroblasts abundant?
cell rich zone
what do fibroblasts produce?
collagen matrix and ground substance matrix
what zone of the pulp are the undifferentiated mesenchymal cells abundant?
cell rich zone
what are the functions of the undifferentiated mesenchymal cells?
1: can differentiate into different cells
2: reservoir for lost cells
are inflammatory cells normally present in pulp?
yes, in low numbers
when do the number of inflammatory cells in the pulp increase?
during inflammation/injury
what are acute inflammatory cells seen in the pulp?
neutrophils
what are chronic inflammatory cells seen in the pulp?
lymphocytes, plasma cells, macrophages
cells of the immune system compromise what % of the cells in the normal dental pulp?
8%
what are the intercellular components of the pulp?
1: intercellular fluid
2: ground substance
3: collagen fibers
4: blood vessels
5: nerves
intercellular fluid is derived from what?
plural capillaries
what are functions of the intracellular fluid?
vehicle for nutrients and waste removal
what makes up the ground substance of the pulp?
1: sol-gel
2: glycosaminoglycans, glycoproteins, and water
3: support cells
what are the functions of the ground substance?
gives the pulp its body and is a transport medium form nutrients
how is composition of ground substance altered by age and disease?
as you get older, the ground substance becomes more fibrous, nutrients decrease and defensive mechanism decreases
what is the role of the ground substance?
1: helps regulate overall intrapulpal pressure
2: acts as a barrier against spread of microbes
how can ground substance act as a defensive mechanism?
can minimize or localize inflammation
what type of collagen fibers are found in dentin?
type I
what type of collagen fibers are found in pulp
type I and III
what type of collagen fibers do odontoblasts produce?
type I only
what type of collagen fibers do fibroblasts produce?
type I and III
collagen fibers are made of what types of chains?
polypeptide chains
what are immature collagen fibers called?
reticular fibers
how are collagen fibers form?
fibrils aggregate to form bundles which in turn form collagen fibers
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