Pulp and Periodontum (complete) Flashcards
What kind of cell creates enamel
Ameloblasts
What kind of cell creates dentin
Odontoblasts
What percentage of enamel becomes mineralized
98%
What is the structure of dentin similar to
it is similar to a bundle of straws. it has tubes that pass all the way through it. from the dentinoenamel junction to the pulp
What can be found in the tubes of the dentin
Nerve Endings
What is the periodontal ligament
lots of ligaments that hold the tooth to the alveolar bone
What is the layer of the tooth that the periodontal ligament attaches to
the cementum
What is the surface of the dentinoenamel junction like
Very rigid with projections all over it ^^^^^^^^^.
Why is the dentinoenamel junction rigidy like this ^^^^^^
it increases surface area, and that allows it to hold the dentin and enamel tightly together
What is the DEJ
the dentino enamel junction
What is the CEJ
The cementoenamel junction
What is the CDJ
the cementodental junction
What can be found in the pulp chamber
- Blood vessels
- Lymph vessels
- Nerves
What is an abscess tooth
a tooth that has had infection in it, but because the tooth is rigid, the swelling from the infection has no option but to push out of the apex of the tooth and form a pool of infection in the surrounding bone at the apical end of the root
What is the dental pulp
the loose connective tissue found inside the tooth
What is the function of the dental pulp
to form and support the dentin
What initiates the formation of enamel
the odontoblasts
how do odontoblasts initiate the formation of enamel
at the basal membrane they interact with dental epithelium and signal it to start creating enamel
What are the only kind of nerve fibers in the tooth
Autonomic (sympathetic) nerve fibers
What kind of neural receptors or sensory neurons are found in the pulp
Nociceptors (pain sensing neurons)
What do nociceptors do?
They only send pain signals when stimulated
Are nociceptors in the dentin as well as in the pulp
yes, nociceptors are in both
Does the pulp chamber respond to external stimuli
yes, the nerves in the pulp chamber and in the dentin will respond to external stimuli
Can dentin be reformed?
Yes it can
How is dentin reformed
new odontoblasts are differentiated, and those form the new dentin
How many of the components of the immune system can be found in the tooth
All components of the immune system
What is endodontics
a dental specialty that involves the diagnosis and treatment of diseases of the pulp and periapical tissues
What is the goal of endodontics
the prevention of treatment of apical periodontitis
What are the 5 signs of inflammation
- swelling
- heat
- redness
- loss of function
- pain
What happens to the pulp chamber with age
It shrinks
What causes the pulp chamber to become smaller as we get older
the continued growth of dentin down into the pulp chamber
At what point in embryonic development do the teeth begin to form
the 6th week
Does the lack of formation of a primary tooth have any indication of potential lack of the succedaneous permanent tooth
yes, if you are missing the primary tooth there is a good chance you will also be missing the permanent tooth
What are the three stages of tooth development
- BUD
- CAP
- BELL
What is the IEE/IDE
the inner enamel epithelium
of the internal dental epithelium
What is the Inner enamel epithelium
(in the bell stage of tooth development)
It forms the internal/inferior border of the bell shape between the invagining Dental papilla and the Stellate reticulum. It marks where the dentinoenamel junction will eventually be
What is the Outer enamel epithelium
(in the bell stage of tooth development)
it forms the outer/superior border of the bell shape, and holds the stellate reticulum in place. It will eventually form the outermost layer of enamel on the crown of the tooth
What is the stellate reticulum
The liquid goo that the body of the enamel comes from
What is the dental papilla
The invagination into the bell shape of the forming tooth. This will become the PULP TISSUE
What builds cemetum
cementoblasts
True or false the dentin is lined with cementum
True
What is the enamel organ (dental organ)
The bell shaped downward growth
from what germ layer does the enamel organ come
the Ectoderm
What is responsible for amelogenesis
the enamel organ (dental Organ)
What is amelogenesis
the creation of enamel
From what type of cells does the dental papilla (dental pulp) come
It comes from neural crest cells and mesenchyme cells
it is ectomesenchymal in nature
Where are the ameloblasts and odontoblasts that begin to lay down tooth material at the basal lamina from
the Ameloblasts are from the IEE/IDE
The odontoblasts are from the outermost layer of the dental papillae
What is going on with theIDE and ameloblasts at the late cap stage
the IDE has differentiated into Ameloblasts but no enamel has been laid down
What is going on with the dental papilla and the odontoblasts at the late cap stage
The outer layer of the dental papilla hasn’t differentiated into odontoblasts yet
What happens in the bell stage with the dental papilla and the odontoblasts
after the outermost cells of the dental papilla have differentiated into odontoblasts. they begin to lay down dentin in the bell stage (before enamel gets laid down)
What are the steps that lead to the beginning of the laying down of the dentin and the enamel
- cells of the IDE/IEE signal to the preodontoblasts
- That causes the odontoblasts to begin dentin formation
- cells from the IDE/IEE respond to signas from the odontoblasts and begin to deposit enamel
What comes first, the dentin or the enamel
the dentin
What happens to the ameloblasts as they mature
- they become long and columnar
2. they eventually lose their nucleus
What happens to the odontoblasts as they mature
- They have the majority of the cell (with the nucleus) towards the apical end of the developing tooth, with a small rod like extension toward the basal lamina
- They keep their nucleus
What is the direction in which all teeth form
all teeth form from crown to root
What is the cervical loop
- The place where the IDE/IEE and ODE/OEE meet.
2. the most apical point of the bell shaped thing
In which direction is the dentin being deposited
in an apical direction
how quickly does dentin get deposited
4.5 um per day
What is the first layer of dentin deposited called
primary dentin (it makes up the mantel dentin)
What is predentin
the most internal layer of dentin that remains unmineralized
What are the percentages of the components of mature dentin by weight
70% inorganic material (calcium hydroxyapetite)
20% organic material (type I collagen)
10% water
What is the significance of the cervical loop
- it is the end of the anatomical crown
2. it is the place where root formation begins
What is HERS
Hertwig’s Epithelial root sheath
What makes up HERS
the combination of the IDE/IEE and ODE/OEE becoming fused and proliferating apically
What does HERS do
- signals for the differentiation of odontoblasts
2. Acts as a template for the root
Is cell proliferation genetically determined
yes
What causes the formation of multiple roots
opposing segments of HERS proliferating both horizontally and vertically
What is the epithelial diaphragm
toward the apex of the root HERS segments move horizontally (where they move horizontally is the epithelial diaphragm)
What is the Hyaline Layer of HERS
The innermost cells of the HERS
what does the Hyaline layer of HERS do
it secretes hyaline over the new dentin, and help bind cementum to the dentin
Where do the cementoblast cells around the root come from
they form when the HERS cells fragment, and allow CELLS of the dental follicle to contact the dentin.
Those CELLS differentiate into cementoblasts
What is the purpose of the cementum
it achors the PDL to hold the tooth in the socket
What are the epithelial cell rests of Malassez
They are the cell remnants of HERS that remain in close proximity to the root
What is the significance of the epithelial cell rests of Malassez
Inflammation can cause these cells to form cysts
When is root formation usually complete
approximately 3 years post eruption
How does the root lengthen
The tooth itself moves toward the surface, while the root grows downward
What causes the formation of multiple roots
it is guided by HERS
lateral extensions of HERS meet in the middle of the forming root, then they join together in the middle and cause a bifurcation which guides the root to form multiple roots
What are the parts of the root canal system or pulp (from incisal/occlusal to apical)
- Pulp Horns
- Pulp Chamber
- Root canal Orifice
- Root Canal
- Apical foramen
What are Pulp horns
vertical extension out of the pulp chamber
What is the pulp chamber
the largest opening in the pulp, defined by anywhere above the root canal orifices
What is the root canal orifice
the openings of the root canal into the pulp chamber
What is the root canal
The long tubes in the pulp that run from the pulp chamber to the apical foramen
What are lateral/accessory canals
Channels of communication between the pulp and the PDL. excluding the apical foramen
How do lateral/accessory canals form
they form when a localized area of HERS is fragmented
How does the apical foramen become formed
- HERS continues to extend to a predetermined length
- HERS moves laterally and encloses more pulp
- Once all different portions of hers have converged until they have nearly met. the space left between them in the apical foramen
What enters through the apical foramen
- blood vessels
- Nerves
- Lymph vessels
Where is the apical foramen located during the process of root formation? and where is it located when root formation is complete
- During the root formation process it is located at the end of the anatomical root
- When root formation is complete (3 yrs post eruption) the apical foramen is slightly more coronal than before (due to cementum formation)
What happens to the apical foramen from when it is first formed to when the root is finished
- it becomes smaller
2. it has moved slightly coronal
What causes the apical formation to move coronal and become smaller as the root formation process is finished
The addition of cementum to the root of the tooth and into the apical foramen
Is there a difference between the anatomic/radiographic apex and the apical foramen
Yep, the anatomic/radiographic apex is more apical than the apical foramen
Why is it important to know that the anatomic/ radiographic apex is different from the apical foramen
When performing a root canal, the tooth must be filled to the apical foramen, and not further to the anatomic/radiographic apex. if it is filled all the way to the anatomic/radiographic apex it will fail.
What causes the anatomic/radiographic apex to be different from the apical foramen
the addition of cementum into the apical end of the tooth. as it is added it pinches off the root, and makes the opening smaller.
How far into the apical end of the root is cementum added
just up to the apical foramen
Are Periodontal ligaments attached to the apical end of the root.
yes, they are attached up until the apical foramen, or anywhere that there is cementum
How is the CDJ important near the apex of the tooth
where the CDJ comes to the interior surface of the tooth is where apical constriction is at its greatest, or the location of the apical foramen
What ends and what begins at the apical foramen
The pulp ends and the PDL begins
how do the hyaline layer interact with the cementum
the cementum is laid over the hyaline layer, and that hyaline layer binds the cementum to the dentin
What are sharpeys fibers
they are the part of the PDL that is imbedded into the Cementum
What are the two things that the PDL is directly bound to
- Cementum on the tooth side
2. Lamina Dura on the bone side
What is the lamina Dura
Very dense bone at the edge of the alveolar socket to which the PDL attaches
What are the types of CEJs and what are the percentages of their frequency
- 60% - the cementum overlaps the enamel
- 30% - the cementum and enamel are edge to edge
- 10% - the enamel and cementum don’t quite meet up
Does the thickness of cementum around the tooth vary from coronal to apical end of the root
yes, the cementum layer is thicker toward the apical end of the tooth than it is toward the coronal end of the root
What are the types of Dentin
- primary
- secondary
- tertiarty
What is the primary dentin
It is the first layer of dentin laid down, usually there when you are born. This includes the mantle dentin
What is the mantle dentin
the most coronal portion of the dentin that is very dense.
What is the secondary dentin
as you age, more dentin is added to the inside of the tooth. This dentin is secondary dentin
does the secondary dentin maintain tubular continuity with the primary dentin?
yep
What does it mean that secondary dentin maintains tubular continuity with the primary dentin
that the tubes through the primary dentin are continued through the secondary dentin into the pulp
What is teritiary dentin
its less organized irregular dentin
Does the tertiary dentin maintain tubular continuity with the secondary dentin
some times it does, sometimes it doesn’t. it depends on the type of tertiary dentin
What are the types of tertiary dentin
- reactionary
2. reparative
What is the difference between reactionary and reparative tertiary dentin
- reactionary tertiary dentin is added by the original odontoblasts, and is there for tubular
- Reparative tertiary dentin is added by new odontoblasts, and is therefor atubular
What are the different types of cells in the dental pulp
- odontoblasts
- dental pulp stem cells
- fibroblasts
- dendritic and antigen presenting cells
where are the odontoblasts in the dental pulp
they are on the outer surface of the dental pulp
How do the odontoblasts in the dental pulp differ from the coronal to apical end of the tooth
they are more numerous and larger in the coronal pulp than they are in the cervical and mid root of the pulp
What happens to the odontoblasts of the dental pulp
- some apoptose
- some die and are replaced by stem cells
- some live and continue to build dentin
What do dental pulp stem cells do
they differentiate into new odontoblasts
What do the fibroblasts of the dental pulp do
They produce collagen and ground substance
What is the most common cell type in the dental pulp
fibroblasts
can fibroblasts in the dental pulp be replaced
yes, by less differentiated cells
what do the dendritic and antigen presenting cells do in the dental pulp
They are cells of the immune system
What is the inner most layer of dentin like
it is predentin, which means that it is not yet mineralized
What is the difference between intertubular dentin and peritubular dentin
- intertubular dentin is all of the dentin between the tubules, and peritubular dentin is the dentin directly around the tubules
- Intertubular dentin has more collagen fibrils than peritubular dentin
- Peritubular dentin is harder than intertubular dentin
How does the exterior (near enamel or cementum) end of the dentin tubules compare to the interior (near pulp) end of the dentin tubules
the ends of the tubules near the enamel are much smaller in diameter than the end of the tubules near the pulp.
What are pulp stones
calcification or creation of stones in the pulp
When are pulp stones most common
in aged, chronically inflamed, or traumatized pulp
what is the largest blood vessel that enters the apical foramen
the arteriole
Where does the innervation of the tooth come from
the 2nd and 3rd divisions of the trigeminal nerve
Are the nerves in the tooth myelinated or unmyelinated
both
