Biology and Histology of Pulp and PA Tissues Flashcards
what is a pulpal organ
central mass of a tooth consisting of soft tissue that is densely innervated by afferent fibers, sympathetic fibers, vascular structures, lymphatics and specialized cells such as odontoblasts and fibroblasts
what cells are found in pulp and what is the most common cell type in pulp
fibroblasts- most common
odontoblasts
what are the primary functions of the pulpal organ and describe each
- formative: odontoblasts- dentin and ameloblasts -enamel
what are the secondary functions of the pulpal organ
supportive
- protection
- sensation
- defense
- repair
what do fibroblasts arise from
undifferentiated ectomesenchymal cell
what do fibroblasts do
elaborates type I and II collagen fibers and ground substance
- wound healing
- pulpal regeneration
what do odontoblasts do
- unique to the pulp
- responsible for dentinogenesis
- amelogenesis
- produced collagen fiber and proteoglycan matrix which becomes mineralized
where do odontoblasts processes extend into
tubules
what nerves innervate the pulp
-trigeminal nerve V2 and V3 in maxillary and mandibular
- PM from mylohyoid
- cervical spinal C2 and C3
IA block alone may provide _____
insufficient anesthesia
are the nerves that supply dental pulp myelinated or not
both
which fibers are the largest diameter in order of largest to smallest
A alpha > A beta> A gamma> A delta > C fibers
what fibers are fastest to slowest
A alpha> A beta> A gamma> A Delta > C fibers
which fiber is unmyelinated
C fibers
describe A fibers
- low stimulation threshold, quicker response, pain characteristics are sharp and pricking
describe C fibers
- high stimulation threshold
- slow in onset
- dull and aching and more diffuse less bearable pain
what should you think with A fibers
acute pain maybe RP
what should you think with C fibers
chronic damage, IP, pulpal pain
what is Branstromms hydrodynamic theory
anything that causes movement of the fluid within the dentinal tubules causes pain in the pulp
what are the common etiologies of pulp irritation
- microbiological
- mechanical
- chemical
-trauma
the pulp is amazingly resilient if covered by at least ______
0.5mm of healthy dentin
reasonable trauma to the pulp can be survived if____
bacteria are minimized or eliminated
many of the etiologies of pulpal damage are ____
iatrogenic
describe pulp polyp (hyperplastic pulpitis)
doesnt hurt but cant heal
describe the response of dental pulp to aging
uniform deposition of tertiary dentin reducing the size of the pulp but retaining the general form as the tooth ages
what is another name forcalcific metamorphosis
pulp sclerosis or dystrophic calcification
what is calcific metamorphosis
- a combo of secondary or tertiary dentin formation in response to extensive and chronic injuries befoer the pulp became necrotic
- no deposition unless pulp is vital
what is the #1 threat to health of the dental pulp
caries
how big are bacteria
0.2 - 5 um
how big are tubules
50 um
what are the most common causes of portals of assess of microbiological irritants
caries and leaking restoration
what is the central goa of RCT obturation
to seal all portals of access
what does cutting with insufficient coolant cause
- aspiration of odontoblasts into tubules
- cooking of the pulp in its own juices
- if beyond limits of repair = pulp necrosis
what temperature does pulp necrosis occur at
10 degrees celsius
what do mechanical irritants cause
- excessive air drying of exposed dentin: aspiration
- application of desiccants: alcohol ,chloroform , cavi
- pulp exposure
what can mechanical irritants be
polishing
- use of laser
what does tertiary dentin do
- deposited over time in the immediate area of the injury by fibroblasts in an attempt to repair, protect, or insulate the pulp from further injury
- general form of pulp it altered
what layers tertiary dentin
fibroblasts
what are external accidents cause by
falls and sports accidents
what is internal trauma caused by
para- normal habits like bruxism
what irritating or toxic elements can cause pulpal injury
- direct pulp cap or indirect pulp cap
- disinfecting agents
- acidic preparations
- composites
what is the diameter and velocity of conduction of A alpha fibers
- 12-20 um
70-120 m/sec
what is the diameter and velocity of conduction of A beta fibers
- 5-12 um
- 30-70 m/sec
what is the diameter and velocity of conduction of A gamma fibers
- 3-6 um
15-30 m/sec
what is the diameter and velocity of conduction of A delta fibers
- 1-5 um
- 6-30 m/sec
what is the diameter and velocity of conduction of C fibers fibers
- 0.4-1
- 0.5-2 m/sec
what is the diameter and conduction velocity of A alpha fibers
12-20 um
70-120 m/sec
