01 pulp biology, last minute studying Flashcards
what are the most prominent immune cells of the dental pulp?
dendritic cells
what is the composition of dentin? (inorganic, organic, water)
Inorganic=70 % (calcium hydroxyapatite)
organic=20% (mainly type I collagen)
water=10%
what do fibroblasts synthesize?
Synthesize: TypeI,III Collagen, Proteoglycans/GAGs (Ground Substance)
-Most common cell type in pulp, abundant in Cell-Rich zone
fibers of the pulp, which is the most and what types?
Collagen types I and III in pulp, produced by
fibroblasts in 55:45 ratio, thus type I is the most abundant
c shaped canal
-Has complex internal anatomy
-Is most commonly found in the Asian population
-Usually occurs in mandibular 2nd
-Should be referred to an endodontist for tx
molars
what is the most important function of the pulp?
formation-odontoblasts form dentin
what is the increased permeability of dentin closer to the pulp due to?
Increased permeability of dentin closer to pulp due to wider, more concentrated dentinal tubules
what cells are present in the cell rich zone of the pulp?
Zone containing high proportion of fibroblasts, immune cells (i.e.: macrophages, dendritic cells), and undifferentiated mesenchymal stem cells
what is the pulp proper and what is the most common cell type present?
Central mass of pulp, consisting of loose connective tissue, larger blood vessels and nerves
-Most common cell type in this layer is the fibroblast
what do fibroblasts synthesize?
Synthesize: Type I,III Collagen, Proteoglycans/GAGs (Ground Substance)
what cells are ‘Present in injured pulps only?’
Mast cells, secrete histamine and heparin to mediate inflammation
where are collagen fibers more prominent?
Collagen fiber bundles more common in radicular pulp than coronal pulp
Extensive branching of blood vessels occurs in subodontoblastic layer (cell free)
forming plexus called…
Sub-Odontoblastic Terminal Capillary Network
what veins do the venules of the pulp drain into?
Venules are slightly larger than arterioles and drain into maxillary vein (posteriorly) or facial vein (anteriorly)
Regulation of Pulpal Blood Flow
Sympathetic Autonomic regulation (healthy pulp):
- Release of NE causes vasoconstriction of pulpal blood vessels
- Normal pulpal vasomotor tone is regulated by sympathetic autonomic system (slight vasoconstrictive tone on precapillary sphincters)
in an inflammed pulp, regulation of blood flow…
neuronal regulation…vasodilation and increased vascular permeability
- Neuropeptides – pro-inflammatory mediators
- AKA NEUROGENIC INFLAMMATION (Acute inflammatory response)
vascular changes during inflammation:
Vasodilation of Vessels
increase in Vascular Permeability
increase in Interstitial Tissue Fluid/Proteins
Pulp has 2 types of sensory nerve fibers:
- Myelinated Axons: A-fibers (20%)
-A-delta fibers (90%)
-A-beta fibers (10%) - Unmyelinated Axons: C-fibers (80%)
where is the Plexus of Rashkow
subodontoblastic cell free zone
where do A fibers and C fibers terminate?
A fibers terminate as unmyelinated free nerve endings in and around the odontoblasts
-C fibers terminate in the pulp
Fastest conducting myelinated pulpal fibers
Pressure and touch sensation (proprioceptive)
A-beta fibers
Slower conducting myelinated fibers
Pain, temperature, and touch sensation
A-delta fibers
Slowest conducting unmyelinated fibers Pain sensation
C fibers
All Sensory Nerve Fibers in pulp/dentin function only as
Nociceptors (Pain)
ALL Afferent impulses generate the sensation of Pain
have higher conduction velocities, relatively Low thresholds for excitation, and pain characteristics of Sharp, Pricking pain
A-delta fibers
have lower conduction velocities, High thresholds of excitation, and pain characteristics of Dull, Aching, Throbbing pain
C fibers
- associated with tissue injury
- less bearable
parasympathetic, sympathetic, or both in pulp?
sympathetic,
Cold Testing Activates which fibers
A-delta fibers
types and location of Cementum
- Acellular afibrillar cementum:
Covers the teeth at and along the cemento-enamel junction (CEJ) - Acellular extrinsic fiber cementum:
Confined to the coronal half of the root - Cellular intrinsic fiber cementum: is - Confined to the apical half of the root
Covers the teeth at and along the cemento-enamel junction (CEJ)
- Acellular afibrillar cementum:
cementum Confined to the coronal half of the root
Acellular extrinsic fiber cementum:
cementum - Confined to the apical half of the root
Cellular intrinsic fiber cementum:
cells of the PDL
-all the same cells as the pulp, but Unique to PDL: Cementoblasts, Odontoclasts, Osteoblasts, Osteoclasts, Epithelial cell rests of Malassez
nerve supple of PDL
Much greater proportion of Propriorecptive A-beta fibers – Allows patient identification of tooth with apical periodontitis
what is Alveolar Bone Proper?
Aka: Bundle bone, Cribriform plate
Compact lamellar bone that lines the socket
Principal periodontal fibers are anchored
Denser than underlying Cancellous bone
Radiopaque appearance on radiographs: Lamina Dura
Radiographic loss of lamina dura = periapical inflammation
