Term
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Definition
-lined by a thin epithilium -overlies ectomesenchyme |
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Term
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Definition
Type of embryonic connective tissue that is derived from the neural crest |
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Term
| Early Development - Primary Epithelial Band |
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Definition
-forms after 5th week of embryo -continuous linear epith thickeneing on the presumptive mandibe and maxilla -corresponds to future dental arches Gives Rise To: 1. Vestibular Lamina 2. Dental lamina |
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Term
Early Development - Primary Epithelial Band Vestibular Lamina |
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Definition
-arises through proliferation of epithelial cells in ectomesenchyme with subsequent degeneration -forms the space b/w the cheeks/lips, and alveolar process aka the vestibule
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Term
Early Development - Primary Epithelial Band Dental Lamina |
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Definition
-series of localized cellular proliferations (dental placodes) -occurs along primary epthelial band -correspondes to sites of future teeth -arises just prior to vestibular lamina -forms all subsequent epithelium |
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Term
Early Development The placement of developing teeth |
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Definition
-determined through Pax-9 expression -tooth formation initially driven byy dental epithelium (action of Bmp-2, Bmp-4, and Fgf-8) -taken over by ectomesenchyme -Day 11 of embryogenesis = earliest sign of tooth development ->thickening of the future tooth bearing area on the first branchial arch -no ectomesenchyme = no tooth |
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Term
Early Develoment Patternening of Dentition (2 Theories) |
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Definition
-placement of various tooth forms in right place -mech is disputed (2 Theories) (evidence of both) 1. Field Model -ectomesenchyme contains overlapping populations of cells thjat secrete factors that act in combination to determine patter 2. Clone Model -specific ectomesenchymal cells that influence the epithelium to produce a certain patter |
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Term
Stages of Tooth Development (4) |
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Definition
1. Bud Stage 2. Cap Stage 3. Bell Stage 4. Crown Stage |
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Term
Stages of Tooth Development Bud Stage |
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Definition
-initial proliferation of dental lamina into underlying ectomesenchyme -teardrop shape -peripheral columnar cells surrounding densly packed central polygonal cells |
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Term
Stages of Tooth Development Cap Stage |
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Definition
-increasing cellular proliferation -epithelial bud of dental lamina increases in size -assums bluntly crescent shape -adjacent, localized numerical increase (condensation) of ectomesencymal cells -called TOOTH GERM
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Term
Stages of Tooth Development Cap Stage Tooth Germ |
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Definition
Consists: 1. Enamel (dental) organ -epith component forms enamel 2. Dental papilla -below enamel organ; ectomesenchymal component forms dentin and pulp 3. Dental follicle - ectomesenchyme that surrounds dental papilla -gives rise to: cementum, periodontal ligament, and alveolar bone = periodontium
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Term
Stages of Tooth Development Bell Stage |
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Definition
-histodifferentiation and morphodifferentiation -started by increasing convexity of undersurface of enamel organ = determines shape of crown -well-defined tissues and cell types seen such as: 1. enamel organ 2. transient structures of the enamel organ 3. dental papilla -dissolution of dental lamina -folding of the IDE due to diff rates of mitotic activity =deliniates shape of the future crown of tooth |
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Term
Stages of Tooth Development Bell Stage Enamel Organ - Structure |
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Definition
External Dental Epithelium (EDE) Stellate Reticulum Inner Dental Epithelium (IDE) Stratum Intermedium Cervical Loop |
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Term
Stages of Tooth Development Bell Stage Enamel Organ - Stellate Reticulum |
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Definition
-cells in center secrete glycosaminoglycans -cause osmotic influx of water -retain attachment to neighbors -become markedly distended |
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Term
Stages of Tooth Development Bell Stage Enamel Organ - External Dental Epi |
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Definition
-cells at periphery of dental organ -closest to oral cavity -become cuboidal in shape |
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Term
Stages of Tooth Development Bell Stage Enamel Organ - Inner Dental Epi & Stratum Intermedium
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Definition
-cells adjacent to dental papilla differentiate along 2 routes: 1. IDE -columnar in shape -increased glycogen content 2. Startum Intermedium -between IDE and stellate reticulum -multilayered -high degree of alkaline phospatse activity |
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Term
Stages of Tooth Development Bell Stage Enamel Organ - Cervical Loop |
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Definition
| Region where EDE and IDE meet |
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Term
Stages of Tooth Development Bell Stage Transcient Structures of the enamel organ (3) |
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Definition
1. Enamel knot: -aggregate of epithelial cells -sits b/w startum intermedium + stellate reticulum -molecular evidence: may contribute to cusp development 2. Enamel cord: -continuation of enamel knot -intersects with EDE 3. Enamel niche -artifact |
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Term
Stages of Tooth Development Bell Stage Dental papilla |
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Definition
-thick basment membrane -develops b/w IDE and dental papilla -forming acellular zone -cells of the dental papilla and dental follicle are still UNDIFFERENTIATED
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Term
Stages of Tooth Development Crown Stage |
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Definition
-begins with onset of dentin formation -late bell -> IDE stop dividing and begin to differentiate into PREAMELOBLASTS -occurs initially at future cusp tips and then proceeds down the cusp inclines -ectomesenchyme cells stop formation of preameloblasts and differentiate into odontoblasts that begin secreting predentin -induces preameloblastas to secrete enamel matrix -thus preameloblasts become ameloblasts -dentin and enamel formation continues -odontoblasts migrate towars pulp for duration of secretory
-ameloblasts migrate away from pulp for duration of secretory
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Term
| Development of Permanent Dentition |
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Definition
-as primary teeth develop: local proliferation of dental lamina near junction w/enamel organ -makes a cluster of cells that lies lingual to side of tooth germ -eventually gives rise to permenant tooth Molars hav no primary counterparts: -form by continuing posterior growth of dental lamina underneath oral epithilium -gives rise to 3 extra germ layers -sprout molar tooth germs at regular intervals 1st Molar = enamel organ forms 4 months in utero 2nd Molar = enamel organ forms 10 months postnatal 3rd Molar = enamel organ forms 5 years old |
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Term
Randomness I wrote down so Ill make a card for it Glands of Serres |
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Definition
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