Bio and Histo of Pulp Flashcards
What is the pulpal organ?
Central mass of a tooth consisting of soft tissue that is densely innervated by afferent (sensory) fibers, sympathetic fibers, vascular structures, lymphatics and specialized cells such as odontoblasts (characteristic cells of pulp) and fibroblasts (most common/prevalent cell type in pulp)
dental lamina
bud stage
bell stage
cap stage
- arrow points to dental papilla
What does the cell-free zone (of Weil) do?
reduces the metabolic activity of the pulp
What is the function of odontoblast?
- Responsible for DENTINOGENESIS
- Important in amelogenesis
Primary Dentin secreted ________ root formation
before
Secondary Dentin formed ______ root formation
after
What do odontoblasts produce?
- Produces collagen fiber and proteoglycan matrix which becomes mineralized . Pre-Dentin
Where do odontoblast processes extend into?
tubules
odontoblasts
odontoblasts
What do fibroblasts arise from?
arises from undifferentiated ectomesenchymal cell
What do fibroblasts do?
WOUND HEALING- FORMS TERTIARY DENTIN
- Elaborates Type I & III Collagen fibers and ground susbtance (important for pulp regeneration)
- tertiary dentin is layered pulpally by fibroblasts
What is the most prevalent cell in the pulp organ?
fibroblasts
fibroblasts
What are the primary functions of the pulp?
*INDUCTION
*FORMATIVE
What are the secondary functions of the pulp?
*PROTECTION
*DEFENSE AND REPAIR
*NUTRITION
What are the principle sensory innervations of the pulp in max and mand?
Trigeminal nerve (V2 and V3)
Additional premolar innervation comes from what nerve (especially in premolar area)?
mylohyoid nerve
Sympathetic (motor) innervation for the pulp is from…
T1 and T2 via superior ganglion
Why might you have to anesthetize the pulp?
IA block alone may provide insufficient anesthesia
The dental pulp is supplied by both…
myelinated and non-myelinated n. axons
What are the characteristics of A fibers?
sharp, pricking
What are the characteristics of C fibers?
dull, aching and more diffuse less bearable pain
Which fibers have relatively high stimulation threshold, slow in
onset (late)?
C fibers
Which fibers have relatively low stimulation threshold, quicker response, pain?
A fibers
Which fibers are associated with early sharp pain (acute)?
A fibers
Which fibers are associated with dull, diffuse pulpal pain (chronic)?
C fibers
What type of fibers are associated with reversible pulpitis?
A fibers
What type of fibers are associated with irreversible pulpitis?
C fibers
About 90% of the fibers are…
A delta fibers
What is Branstromm’s “Hydrodynamic Theory”?
Anything that causes movement of the fluid w/in the dentinal tubules causes pain inthe pulp
Many of the etiologies of
pulpal damage are…
IATROGENIC
The pulp amazingly resilient if covered by at least _____ mm of healthy dentin
.5mm
*reasonable trauma can be survived if bacteria are minimized or eliminated
What are the common etiologies of pulp irritation?
- Microbiological
- Mechanical
- Chemical
- Trauma
What are the portals of acess of microbiological irritants to the pulp?
- Cracked or fractured tooth
- Cemental defect @ CEJ
- Open dental tubules
- Perio invasion into apex
- Pulpal invasion in P/A
- Lateral or Accessory Canal
What is the most common cause of access of microbiological irritants to the pulp?
caries/leaking restoration
How big are bacteria compared to the tubules?
Bacteria are 0.2 to 5 um
Tubules are 50 um
What is the central goal of RCT?
to SEAL ALL PORTALS of ACCESS
The #1 threat to health of the dental Pulp is…
DENTAL CARIES
Without microbes & their products, LEOs (Lesions of Endodontic Origin)…
do NOT occur
What is this?
pulp polyp
(hyperplastic pulpitis)
*doesn’t hurt- can’t heal
Most operative procedures are accompanied by significant opportunity for…
iatrogenic and irreversible damage to the pulp
What does cutting with insufficient coolant cause?
Aspiration of odontoblasts into tubules
What is the hottest temp that the pulp can get before it is beyond repair?
42 C
What happens if the pulp gets damaged beyond repair by a mechanical irritant?
Pulp Necrosis
What are different types of mechanical irritants to the pulp?
- Excessive air drying of exposed dentin: aspiration
- Application of desiccants: alcohol, chloroform, Cavit, etc.
- Polishing
- Use of laser
What is the response of the dental pulp to injury in the immediate area of the injury?
fibroblasts lay down tertiary (reparative) dentin
- general form of the pulp is altered
What is a chemical irritant?
Application of any irritating or toxic element to the pulp or dentinal tubules may cause pulpal injury
What are the different chemical irritants for the pulp?
- Direct Pulp Cap or Indirect Pulp Cap (CaOH has pH of 12)
- Disinfecting agents
- Acidic preparations
- Composites
What are types of external trauma to the pulp?
Falls & Sports Accidents
What are types of internal trauma to the pulp?
Para-Normal Habits (Bruxism)
What is calcific metamorphosis?
- Pulp sclerosis or Dystrophic calcification
- Probably a combination of 2ndary and Tertiary dentin formation in response to extensive and chronic injuries before the pulp became necrotic. (no deposition unless pulp is vital)
*also comes with age
When is calcified material is deposited?
only when the pulp is vital
What is the typical response of the Dental Pulp to Aging & Injury?
Calcific Metamorphosis
The uniform deposition of ___________ __________ reducing the general size of the pulp but retaining the general form as the tooth matures
SECONDARY DENTIN
What is the function of odontoblasts?
create tooth structure
