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27 Cards in this Set
- Front
- Back
largest structures in enamel
how big where |
-enamel rods
-4-5 ___ thick, and up to 3mm -extend from DEJ to outer surface |
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Characteristic arrangement of apatite crystals: structures (3)
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-rod core
-interrod substance -rod sheath |
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in cross section enamel rods have a _______ or ______ pattern due to __________
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-"key hole"/"fish scale"
-due to the orientation of apatite crystals |
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Rod core:
apatite crystals are oriented ___________ |
-parallel to long axis of rod
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Interrod substance: orientation of apatite crystals
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-oblique
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rod sheath (2)
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-boundary btw rod core and interrod substance
-due to increase in space and :. protein content |
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aptite crystal:
composed of |
-thousands of modified calcium hydroxyapatite subunits
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calcium hydroxyapatite
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-Ca10(PO4)6(OH)2
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enamel synthesis rate
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-4 ____/day??
-but has diurnal variations (daily imbrication lines) |
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Lines of Retzius (2)
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-product of cyclical variations (7-9 days) in enamel matric production
-also of shape of Tomes' process |
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neonatal line
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-exaggerated line of Retzius
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perikymata (2)
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-shallow grooves
-formed at the surface by the lines of Retzius |
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gnarled enamel (2)
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-found at cusp tips and incisal edges
-consequence of the individual paths taken by ameloblasts/groups of ameloblasts (and :. the enamel rods) |
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Hunter-Schreger bands (3)
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-found in lateral enamel
-made by enamel rods w/ diff orientations -reflect light |
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Enamel spindles (3)
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-area of hypomineralization
-terminal ends of dentinal tubes -tubes were trapped btw ameloblasts during enamel matriz synth |
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Enamel tufts (2)
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-hypomineralized enamel
-extend a bit from the DEJ |
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Enamel lamellae (3)
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-hypomineralized areas
-leaf-like -may extend to surface |
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DEJ is characterized by ______
what is this area |
-"scalloped border"
-specialized zone of transition (btw enamel and dentin) |
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Dentin (2)
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-highly permeable
-numerous dentinal tubules |
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dentinal tubules (2)
how many (2) |
-make dentin permeable
-have S-shaped curves in crown (from inward apposition) -20,000-30,000/mm^2 at DEJ -even more nearer to pulp |
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intertubular dentin
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-normal mineralized dentin
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intratubular dentin (2)
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-highly mineralized sheath
-added to inside of tubule |
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sclerotic dentin (2)
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-formed when tubules are completely occluded by intratubular dentin
-or clinically by use of a sclerosing solution |
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dead tracts
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-groups of empty tubules (only fluid-filled)
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Lines of von Ebner (2)
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-represent changes in collagen matrix orientation
-occur approx every 5 days |
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globular dentin
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-mix of normal and hypomineralized dentin
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regions of hypomineralized dentin
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-interglobular dentin
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