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26 Cards in this Set
- Front
- Back
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The outer most layer of dentin is called? Deep to that is the? Deep to that is the? The most inner part is the? Which is the reparative dentin? |
Mantle dentin Primary dentin Secondary dentin Predentin Tertiary dentin |
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- Dentin is like bone and is cellular - Has odontoblast process in tubules on the inner surface of dentin |
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There are odontoblastic processes in tubules that become __ through the basal lamina and beyond the DEJ As the odontoblast migrate towards the pulp the processes get longer 2 types of dentin around the odontoblast processes? |
Enamel spindles Peritubular dentin Intertubular dentin |
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What is dental pulp? What does it have? |
Connective tissue pulp chamber and root canal (terminates as apical foramen) |
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Predentin is __ and has __ Its like osteoid because bone is laid down first What secretes predentin? |
Unmineralized and has mostly collagen Odontoblasts secrete predentin |
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Dentin is 70% __ What forms the scaffold for mineral to be deposited on? Dentin has elasticity, tight scalloped dentinoenamel junction and a less distinct cementum/dentin junction |
70% inorganic material (hydroxyapatite) -20% organic material (type 3 and 4 collagen and non-collagenous protein) -10% water Type I collagen |
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Dentinogenesis: Begins during what stage? The internal enamel epithelium become presecretory ameloblast which induce? This then starts to produce dentin -The process of dentinogenesis starts at the __ and then later in the? |
Bell stage odontoblast differentiation -come from dental papilla which came from ectomesenchyme -The cuspal region (coronal dentin) -Then later in the root (root dentin) |
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Inner enamel epithelium that are preamloblasts reverse polarity and elongate. The nuclei move toward? Ectomesenchymal cells adjoining the acellular zone rapidly enlarge and must undergo __ and change orientation The preameloblasts signal for some of these cells to __ |
Stratum intermedium Mitosis (to proliferate) differentiate and increase in size to occupy the acelleular zone between dental papilla and presecretory ameloblasts -some remain undifferentiated |
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When presecretory ameloblast change polarity what appears? What gets populated by the above? They then start secreting dentin |
odontoblasts Acellular zone |
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First sign of dentinogenesis after dentin is made is deposition of __ which is made of __ |
von Korff's fibers -made of Collagen III fibers and fibronectin |
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Root dentin starts later at the cervical loop where Hertwig's root sheath induces its formation What does HERS induce? |
odontoblast formation down by the root before tooth eruption |
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Pre odontoblasts cells are __ -they have more cytoplasmic organelles Nucleus becomes polarized located? |
Larger Located at the base of the cell away from the internal dental (enamel) epithelium |
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Secretory odontoblasts are tall columnar cells that synthesize what 3 things? |
Type I collagen and ground substances - Secretes unmineralized dentin = predentin |
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Mineralization occurs what regions? These regions coalesce to form? If the above does not fuse there are uncalcified dentin called? |
calcospherites solid mass of mineralized (globular) dentin inter-globular dentin |
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Odontoblastic processes are within dentinal tubules |
canaliculi are present like in bone |
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What occurs when dentinal tubules become occluded? -Increases with age Tubules in carious lesions may fill with bacteria. Odontoblast processes in these tubules may disintegrate leaving an empty tubule called? |
Sclerotic dentin -can sometimes be repaired with reparative dentin Dead dentinal tract |
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There is a dentinoenamel junction as well as a dentin cementum junction, what is found at the dentin cementum junction? |
Tome's granular layer (arrangement of protein and collagen) |
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Odontoblast deposit dentin in daily increments and every __ days there is a change in orientation of collagen fibers called? |
5 days Incremental lines of von Ebner |
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What are exaggerated incremental lines that reflect change of nutritional status or disease in the individual during the period of dentinogenesis (ie Neonatal line)? |
Contour lines of Owen |
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Pulp is connective tissue with what 4 zones? |
1. odontoblasts 2. cell free zone of weil 3. cell rich zone 4. pulp core |
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*note that cell free zone and beyond has nerve and rich vascular supply |
-Nerve fibers move up into the processes |
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Other cells in the pulp include macrophages, lymphcytes, dendritic cells, and what 2 other things? Collagen (I and III) seen in pulp with matrix components such as glycosaminoglycans, glycoproteins, and water - all things expected in CT |
Fibroblast that make pulp matrix Undifferentiated ectomesechymal cells (dental pulp stem cells) that can transform into fibroblasts or odontoblasts if cell population is reduced after injury |
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In the cell free and cell rich zones are nerve bundles that form the? Some of these nerve fibers end up in the dental tubules with odontoblast processes -detect pain |
Nerve plexus of raschkow |
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