Module 1: Pulp Biology Lecture Flashcards
What week of life does the first invagination of the oral epithelium occur?
6th
What are the three stages of tooth development
Bud
Cap
Bell
What are the three structures of the Developing tooth bud
Enamel Organ
Dental Papilla
Dental Follicle/Dental Sac
Which of the three developmental structures is made of ectodermal cells
Enamel Organ
What cells are formed from the enamel organ
ameloblasts
What cells are formed from the dental papilla
odontoblasts
What cells are formed from the Dental Follicle
Osteoblasts
Cementoblasts
Fibroblasts
During the bell stage, what is deposited first, enamel or dentin?
Dentin, which in turn stimulates ameloblasts to deposit enamel
What is the approximate percentage of hydroxyapatite in dentin?
70%
What is the primary organic component of Dentin
Type I Collagen (20%)
Which is deposited faster, Secondary or Primary Dentin?
Primary
Where is predentin located?
Between Odontoblasts and circumpulpal dentin
Is the dentin tubule wider at the pulp or at the DEJ?
Pulp
Is there a greater density of tubules at the pulp or at the DEJ?
Pulp
Are dentin tubules more permeable at the DEJ or near the pulp?
Pulp
What makes up the bulk of all dentin, Intertubular or Intratubular?
Intertubular
Which sub-type of dentin is harder? Inter or Intratubular?
Intratubular
Which sub-type of dentin is more quickly dissolved by acids?
Intratubular due to higher percentage of mineralization
What can cause post-operative dentinal sensitivity?
Opening of the tubules due to acid etching
What is the earliest response of dentin to carious infection?
Occluding of dentin tubules via mineral deposition (limiting permeability)
What is dentinal fluid exactly?
An ultrafiltrate of blood from the pulpal capillaries found inside the dentin tubules
What is the outermost layer of the pulp?
The odontoblastic layer
What is housed in the odontoblastic layer?
Odontoblast cell bodies
What is housed in the Cell Free Zone of Weil?
The Subodontoblastic nerve plexus of Raschkow and the blood vesell plexus
What are the prominent cell of the cell rich zone?
Fibroblasts
Stem Cells
Dendritic Cells
Macrophages
What is the pulp proper?
The bulk of the pulp, inner core
What is the most common cell in the pulp proper?
Fibroblast
What type of collagen do odontoblasts produce?
Type I
And a tiny bit of Type 5
What do fibroblasts secrete?
Type I and III Collagen
Proteoglycans/GAGs (Ground Substance)
Dendritic cells present Antigens to T Helper cells during what type of immune response
Adaptive
When is the only time you would expect to see a mast cell in the pulp tissue?
When the pulp has already been injured
What type of T lymphocytes are associated with Type IV delayed hypersensitivity?
T Memory Cells
Are there arteries and/or veins in the pulp?
No. Trick Question.
Arterioles and Venules are the largest blood vessels in the pulp
What artery supplies the blood for the mandibular teeth?
Inferior alveolar artery
What artery supplies the blood for the posterior maxillary teeth
Posterior Superior Alveolar
What artery supplies the blood for the anterior maxillary teeth?
Infraorbital Artery
Blood from the teeth drain in to one of these two veins?
Facial (anteriorly) Maxillary Vein (Posteriorly)
What effect due the pulpal lymphatics typically have on the interstitial fluid pressure
they lower it
What neurotransmitter causes the vasoconstriction of pulpal blood vessels
Norepi
When a pulp is inflammed, sensory neurons will release these two transmitters in order to DILATE the pulpal blood vessels and increase vascular permeability. This is called neurogenic inflammation
SP
CGRP
What was the Self Strangulation Theory
Increase in pulpal tissue pressure would strangulate vessels leading the ischemia. THIS IS NOT TRUE!
What saves the pulp from succumbing to the debunked self strangulation theory?
Capillaries have the ability to shunt blood to a localized area of injury so that the entire pulp is not subjected to increased pressure levels
What percent of the nerve fibers in the pulp are myelinated?
20%
Are the myelinated axons A-fibers or C-fibers?
myelinAted
What percent of the myelinAted axons are slow speed alpha delta fibers
90%
What are the high speed myelinated fibers called?
Alpha Beta
Where do the A-fibers terminate?
Around odontoblasts (under, adjacent, in tubules)
Where do the C-fibers terminate
In the pulp proper
Which of the pulpal nerve fibers can transmit pain?
All of them
Which fibers have a low threshold and are responsible for a sharp pricking type pain
A-Delta
What fibers are responsible for the dull, aching, throbbing pain?
C Fibers
According to the hydrodynamic theory how do the A fibers in the dentin tubules tell cold stimuli from hot?
Cold stimuli produces a net outward flow of dentinal fluid
Besides cold, what else causes a net outward flow?
Air
Hyper-Osmotic (Sugar solution)
Which is more painful, cold (outward) or heat (inward)
COLD (outward)
So then what fibers are activated using cold testing?
A-Delta due to outward dentin fluid flow
What percent of teeth have pulp stones of some type?
50%
Out of cellularity, vascularity, innervation, and number/thickness of collagen; which is the only one that increases with age?
Number and thickness of collagen
What type of cementum is at the CEJ?
Acellular
What type of acellular cementum is only found on the coronal half of the root?
Acellular Extrinsic
Where is the cellular Cementum?
In the CELLar (Apical)
What cells are unique to the PDL
Cementoblasts Odontoclasts Osteoblasts Osteoblasts Epithelial Rest Cells of Melassez
Why can patients more easily identify teeth with apical periodontitis?
Because the PDL has a higher percentage of A-Beta sensory fibers
What type of bone is the alveolar bone proper
Compact Lamellar
What is the difference between bundle bone and the lamina dura?
None. The lamina dura is what it is called on a radiograph
What does a radiographic loss of lamina dura indicate?
Periapical inflammation
