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22 Cards in this Set
- Front
- Back
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Two stages of amelogenesis
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-full thickness of enamel matrix is laid down by secretory ameloblasts, and 30% mineralized
-Once the matrix formation is complete, secretory ameloblasts differentiate into maturation-phase ameloblasts which complete mineralization (to 96%) |
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Tome's Process (2)
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-at secretory end of ameloblast
-responsible for orientation of enamel crystals (in rod, interrod substance) |
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List the specialized proteins found in the enamel matrix (6)
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-amelogenins (90%)
-ameloblastins (sheathelin, amelin) -tuftelin -enamelins -serum proteins -serine and metalloproteinases |
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What is the main protein in enamel matrix
what % MW properties (1) AA's function |
-amelogenins
-90% -20-30 kDa -hydrophobic -rich in proline, hist, glutamine -reg crystal growth, location |
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enamel hypoplasia
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-defects in amount of matrix formed
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enamel hypomaturation
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-defects in amount of mineral
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bioapatite
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-highly substituted calcium hydroxyapatite
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Hydroxyapatite:
formula |
- Ca10(PO4)6(OH)2
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Substitution of _____ for ____ increases acid resistance.
Sub of ____ for ____ increases acid solubility of enamel crystal |
- F- for OH-
- CO3^-2 for OH- or PO4^-3 |
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odontoblasts secrete
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-collagen-rich organic matrix
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what reg's tooth(?) mineralization
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-matured organic matrix of odontoblasts
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Contents of Predentin (dentin matrix)(5)
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-Collagen type I
-dentin phosphoprotein -proteoglycans -osteocalcin, osteonectin, osteopontin -matrix gla-protein |
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genetic defects in dentin matrix lead to _____
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-dentinogenesis imperfecta
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primary dentin (3, incl types (2))
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-first, mantle dentin
-then, circumpulpal dentin -4 (?) formed/day |
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2ndary dentin (3)
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-begins after root completion
-much slower than primary -continues throughout life |
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tertiary dentin (3)
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-response to injury
-irregular appearance -2 types: ---reactive dentin ---reparative dentin |
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Types of tertiary dentin
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-reactive dentin:
--formed by odontoblasts -reparative dentin: --formed by mesenchymal cells which differentiate into odontoblasts |
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epithelial root sheath (3)
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-inner/outer enamel epithelia
-NO stratum intermedium, stellate reticulum -regs root # and form |
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interaction btw _____ and _____ induces formation of root dentin
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-inner enamel epithelial cell
-dental papilla |
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disruption of ________ allows dental follicle cells to interact w/ dentin
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-root sheath
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dental follicle cells diff into ________
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-cementoblasts
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Intermediate cementum (4)
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-hyaline layer
-neither true cementum nor true dentin -interface btw dentin and cementum -characterized by interdigitation of collagen fibers (from cementum/dentin matrices) |
