Dental Pulp Chapter 4

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  1. Collagen is the most abundant _______ protein
  2. _______ are the principle cell in connective tissue.
  3. ________ substance is primarily responsible for the ________ and filtration function of connective tissue.
    • Ground substance
    • viscoelasticity
  4. Ground substance is mainly composed of?
    Proteogylcans (Protein core and GAG)
  5. Adhesive glycoprotein?
  6. List layers of pulp from peripheral.
    • Odontoblastic layer
    • cell free zone or zone of Weil
    • cell-rich zone
    • pulp proper
  7. List the main components of the odontoblastic layer
    • Terminal capillary network
    • Nerve fibers (terminal axons from plexus of Rashkow) between odontoblasts
    • Class II MHC dendritic cells
    • Korff fibers
  8. List main components of the cell free zone.
    • unmyelinated nerve fibers
    • blood capillaries
    • process of fibroblasts
  9. List main components of cell rich zone.
    • Fibroblasts (more here than pulp proper)
    • undiff mesenchymal cells
    • defense cells (macrophages/lymphocytes)
    • blood capillaries
    • nerves
  10. How can Korff fibers be identified histologically?
    Silver impregnation
  11. List components of pulp proper.
    • Fibroblasts (most abundant cell type)
    • Larger blood vessels
    • Nerves
    • Undiff mesenchymal cells
    • defense cells like macrophages (in perivascular area)
  12. Collagen fiber bundles are more numerous where?
    Root pulp, therefore clinical implication of barbed broach
  13. What is meant by low-compliance environment of the pulp?
    It is encased in rigid mineralized tissue
  14. What is the self-strangulation theory?
    Increased tissue pressure caused blood vessel compression and resultant ischemia and pulpal necrosis
  15. What physiologic mechanisms does the pulp have to combat the strangulation theory?
    Feedback mechanisms to oppose inc. in tissue pressure (inc. lymph flow and absorption of interstitial fluid into capillaries in non-inflamed areas)
  16. Which neuropeptides modulate vasodilation in the pulp?
    substance P, CGRP, neurokinin A
  17. What are the efferent properties of the pulpal sensory neurons when using substance P and CGRP?
    • modulate extracellular matrix production
    • secondary dentinogenesis
  18. Collagen domain?
    Triple helical
  19. Collagen chains?
    α chains
  20. Collagen assembly?
    • 3 polypeptide chains
    • hydrogen bonds
    • hydrophobic interactions
  21. Collagen distinct two amino acids?
    • Hyroxyproline
    • hydroxylysine
  22. Cells responsible for collagen synthesis?
    • Fibro
    • Chondro
    • Osteo
    • Cemento
    • Odonto
  23. Most common form of collagen?
    Type 1
  24. Type 1 found in?
    Skin, bone, tendon, dentin, pulp
  25. Collagen fibers are made up of _____
    fibrils in characteristic striations every 67nm, hallmark for ID
  26. What differentiates the types of collagen?
    Combinations of linkages of the polypeptide chains
  27. Two main classes of collagen?
    • Fibrillar (Type I, III, V, XI)
    • Non-fibrillar
  28. Collagen II (NF) found in_______
    mostly cartilage, not in pulp
  29. Type III collagen co-distributes with _____
    Type I
  30. Type III collagen found where?
    Reticular fibers (fine fibers) mainly used in embryogenesis, inflammation, and wound healing
  31. Type IV and VII present
    in basement membranes
  32. Type V collagen present in
    unmineralized tissues
  33. Type VI collagen is found
    distributed in body as interfibrillar filaments
  34. Amount of collagen in dried pulp in PM? 3rd molar?
    25.7% vs 31.9%
  35. Type III collagen in pulp, percent and where?
    42.6%, forms thinner fibrils, cell-free and cell-rich zones
  36. Is type I collagen exclusive to pulp?
    NO, but it is definitely to dentin.
  37. What types of collagen can be found in predentin?
    I, III, V
  38. Korff fibers were originally described as
    argyrophilic fibers
  39. Korff fibers pass ______ between the odontoblasts entering the ______.
    • spirally
    • predentin
  40. Korff fibers particularly evident during
    early dentinogenesis, involved with mantle dentin and odontoblast differentiation
  41. Korff fibers mainly composed of which collagens
    I, III
  42. What other collagens have been observed in the pulp?
    • V, VI
    • form dense meshwork of thin microfibrils
    • VI found between odontoblasts toward predentin suggesting comp of Korff
  43. Type IV collagen forms the
    basement membranes of pulpal blood vessels
  44. Describe how CaOH works to induce collagen formation.
    • First produces necrotic zone bc of high pH
    • fibroblast-like cells, inflammatory cells migrate to site
    • formation of new collagen close to necrotic zone with cellular inclusions
  45. GAGs are ____, ______ polymers of repeating __________ units.
    • long
    • unbranched
    • disaccharide
  46. Four main types of GAGs?
    • Chondroitin sulfate/dermatan sulfate
    • heparan sulfate/heparin
    • keratan sulfate
    • hyaluronic acid
  47. The 3D structure of proteoglycans can be likened to
    an interdental brush, the metal is the protein and the bristles are the GAGs
  48. Why are proteoglycans so hydrophilic?
    carboxyl, hydroxyl, sulfated hexosamines
  49. The long GAG chains allow for storage of?
    Water, lots of it, form a shock absorbing gel that protects connective tissue
  50. Since they are cationic, proteoglycans attract
    matrix proteins and GFs like TGF-β, act as a bioactive molecule pool
  51. What is syndecan?
    Proteoglycan on cell membrane, binds collagen, fibronectin, tenascin. Cell-surface receptors that connects matrix molecules to the cytoskeleton
  52. Name the proteoglycans found in consistently in pulp?
    • Chondroitin sulfate
    • dermatan sulfate
    • hyaluronic acid
  53. Dentins main proteoglycan is
    chondroitiin sulfate
  54. Chondroitin sulfate plays what role in dentinigenesis?
    strong capacity to bind calcium and may maintain levels of calcium-phosphate during mineralization
  55. How to proteoglycans mechanically stop bacteria?
  56. How do bacteria counter PGs viscosity?
    Streptococci produce hyaluronidase (hydrolyzes GAGs)
  57. Fibronectin a glycoprotein exists as the three in pulp:
    • 1. plasma protein
    • 2. protein attaches to cells
    • 3. insoluble fibrils form ECM
  58. Fibronectin acts a mediator for ______ and ______ adhesion and thus has major effect on the ____________, ____________, and _____________ of cells
    • cell-cell
    • cell-matrix
    • proliferation
    • differentiation
    • organization
  59. Fibronectin is immunolocalized in the odontoblastic layer where it forms _______ fibers that pass from _____ into _______ parallel to longaxis of OD.
    • corkscrew
    • pulp
    • predentin
    • (which suggests constituent of Korff fibers)
  60. Odontoblasts and fibronectin?
    morphology controlled by
  61. Relations of OD cell bodies predentin and fibronectin?
    FN contributes to tight seal here
  62. FN implicated in reparative dentinogenesis, how?
    Immunolocalized during CaOH capping, allows for diff of OD and migration
  63. Osteonectin is a __________ protein that has affinity for ______ and _________ and promotes the deposition of _______ _______ mineral onto ________.
    • non-collagenous
    • calcium
    • hydroxyapatite
    • calcium phosphate
    • collagen
  64. What non-collagenous proteins are found in the pulp?
    • Fibronectin
    • Osteonectin
    • Bone sialoprotein
    • Osteopontin
  65. Odontoblast nucleus contains up to how many nucleoli?
  66. Diameter of odontoblast process?
  67. Odontoblast processes do/do not extend to the outer dentin
    do not, except during early tooth development
  68. What kind of junctions keep odontoblasts together?
    desmosome-like jxn
  69. What there junctions are common to odontoblasts?
    desmosome-like and gap jxns and tight
  70. Which junction is involved in cell adhesion for the odontoblast?
  71. which junction is involved in pathways for intercellular ion transfer, between odontoblasts?
    gap jxns
  72. What jxn exists where the cell body and process interface is close to another odontoblast?
    Tight jxn, prevent passage of materials between cells
  73. Why is it unclear if the tight junctions encircle the whole odontoblast?
    small nerve fibers and collagen fibers pass through interodontoblastic space, known as macular or "leaky"
  74. What molecule do odontoblasts present making them defense cells?
    TLRs (Toll Like Receptors)
  75. What bioactive substances do odontoblasts secrete?
    • chemokines
    • TGF-β (OD are main source in pulden complex)
    • MMPs
  76. What non-col proteins do OD synthesize?
    • bone sialoprotein
    • dentin sialoprotein
    • dentin phosphoprotein
    • dentin matrix protein 1
    • osteoclacin
    • osteonectin
    • osteopontin
  77. What specific MMPs do OD synthesize?
    • MMP-8 (collagenase 2)
    • MMP-2,9 (gelatinases)
    • MMP-20 (enamelysin)
    • MMP-14
  78. What are thr findings that show OD are involved in innate immunity?
    • 1. express TLRs
    • 2. produce chemokines and express chemokine receptors
    • 3. produce antimicrobial peptides such as β-defensins
  79. TLR-2 recognizes products of
    gram-positive bacteria (lipoteichoic acid)
  80. TLR-4 recognizes
    lipopolysaccharides prod by gram - bacteria
  81. Activation of TLR by microbial ligands causes
    prod of cytokines, chemokines, defensins
  82. Which dentin specific protein marks the odontoblast phenotype?
    dentin sialoprotein
  83. What do fibroblasts produce?
    • Type 1, 3 collagen
    • Fibronectin
    • Proteoglycans
    • Osteonectin
    • Osteopontin
    • Bone Sialoprotein
    • TGF-β1
    • BMP-2,4
  84. Fibroblasts secrete MMPs, which one of these has limited expression in other normal adult tissue?
    MMP-13 (collagenase-3)
  85. What are the antibody secreting cells?
    B-lymphocytes, humoral immunity
  86. What is the main job of T cells?
    cause lysis of other cells that carry foreign antigens
  87. Two types of T cells?
    CD4 helper cells, humoral and cell-mediated immunity

    CD8, cytotoxic, cell mediated
  88. Match MHC to T cell?
    MHC Class I binds to CD8

    MHC Class II binds to CD4
  89. MHC Class I or II is also termed
    HLA, human leukocyte antigen
  90. Expression of MHC Class I and Class II, which cells?
    Class I is expressed on almost all cells

    Class II is expressed on dendritic cells and B lymphocytes (macrophages can be induce)
  91. Where are T lymphocytes scattered in the pulp proper?
    Along the blood vessels
  92. Numbers of CD8 to CD4?
    CD8 outnumbers CD4
  93. Which lymphocytes are rarely found in the pulp?
    B lymphocytes and plasma cells
  94. Macrophage function?
    phagocytosis of foreign particles, self-tissues, injured or dead cells (bone marrow derived cell)
  95. Where are macrophages found in pulp?
    Everywhere but rich in perivascular area of inner pulp
  96. Where are dendritic cells derived?
    hematopoietically derived
  97. Characteristics of dendritic cells (5)
    • 1. dendritic morphology
    • 2. Class II MHC
    • 3. high motility
    • 4. limited phagocyctic
    • 5. potent capacity for antigen presentation
  98. Where do dendritic cells mature and what tissues do they populate?
    • Bone marrow
    • nonlymphoid tissues
  99. Dendritic cells express what factor also seen in cells of the dermis?
    coagulation factor XIIIa
  100. Dendritic cells of pulp reside
    in periphery of the pulp, sometimes compete for space with odontoblasts evening expressing their processes into the tubules
  101. Following ingestion of antigen what two ways may dendritic cells act?
    • 1. migrate to regional lymph nodes to present antigen to naive T lymphocytes to start primary immune response
    • 2. locally present antigens to patrolling T lymphocytes (secondary immune response)
  102. The two types of cells termed pulpal dendritic cells
    Dendritic cells and macrophages
  103. The intensity of inflammatory and immunologice responses correspond to the ______ and ______ of _______ and _________ processes of dentin that influence dentin permeability
    • status
    • quality
    • reactive
    • reparative
  104. ______ et al have demonstrated that the accumulation of _______ cells remains evident even _ months after caries removal with the aid of a caries detector dye and resin restoration with resin.
    • Yoshiba
    • dendritic
    • 6
  105. What is the major function of connective tissue?
    • provide a matrix that binds cells and organs
    • gives support to the body
  106. What is ground substance composed of?
    • Proteoglycan (GAGs and protein)
    • Fibronectin (cell adhesive)
  107. Cell free zone is also known as the zone of _____
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Dental Pulp Chapter 4
2013-08-02 20:22:46

Pulp as a Connective Tissue
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