Term
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Definition
-Teeth must undergo movement from their place of development to thei place of function The movements are: 1. Pre-Eruptive - occurs in jaw before eruption (space out a bit) 2. Eruptive - movement from bone to place of function 3. Post-Eruptive -compensatory movement to maintain function dispite tooth attrition
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Term
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Definition
-Tooth occupies a place within bone, therefore movement requires bone remodeling -Most movement occurs from early crowding of tooth germs in fetal head -Jaw lengthens, crowding alleviated and tooth germs shift to "normal" position -Rotational movement occurs in molars Maxilla: Occlusal surfaces face distally Mandible: Occlusal surfaces face mesially
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Term
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Definition
-Begins after root formation has take place (which also leads to development of PDL) -Contrast to primary, secondary teeth are almost completely encased in bony crypt -Follicle surround tooth communicates with lamina propria through Gubernacular Canal -The Gubernacular Cord (remnant of Dental Lamina) passes through canal, recruits osteoclasts to open space and tooth passes through
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Term
| Proposed Mechanisms for Eruptive Movement |
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Definition
1. Root Formation 2. Bone Remodeling 3. Dental Follicle 4. PDL
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Term
| Eruptive - Root Formation |
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Definition
"The crown of the tooth is propelled upward by force of the developing root" -NO! A force is produced but needs a static object to puch against (which there is none)
-Also rootless teeth can erupt as well as eruption after root is completed
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Term
| Eruptive - Bone Remodeling |
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Definition
"Tooth is forced upward through bone resorption around the Gubernacular Canal and apposition at the crypt base" |
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Term
| Eruptive - Dental Follicle (NOT THE SAME ONE) |
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Definition
This dental follicle is the name for the CT that is adjacent to the crown
"Cells of the REE secrete proteases to degrade collagen and CSF-1 that stimulates the differentiation of osteoclasts"
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Term
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Definition
"Tooth is pulled into position due to contraction of PDL fibroblasts" -But, rootless teeth can erupt and teeth with a fully formed PDL necome impacted
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Term
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Definition
-Eruption mainly driven by Developing PDL -But, root formation, dental follicle activity and bone remodeling do help -Root formation has a larger role in producing a force after tooth clears the gingiva
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Term
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Definition
-Occurs after teeth reach level of occlusion Reasons include: 1. Accomodate continued growth of jaws (via bone apposition) 2. Compensate occlusal wear (attrition) 3. Compensate interproximal wear (mesial drift)
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Term
Mesial Drift Mechanisms (Teeth tend to move towards midline) |
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Definition
1. Anterior Component of Occlusal Force - occlusla table has slight tilt, small forward force 2. Soft Tissue Pressure (cheekls, lips, tongue) - Almost nothing 3. Contraction of Transseptal Ligament - main mechanism, pulling cementum to cementum
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Term
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Definition
-Cementum and dentin of primary teeth are resobed via Odontoclasts (identical to osteoclasts) -Pulp and PDL cells undergo apoptosis -Pressure on primary tooth by erupting secondary decreases its PDL support -After root resorption occurs, the epithelium of DGJ migrates across underside of tooth -Chewing eventually causes tooth to exfoliate
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Term
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Definition
1. Loss of Root Substance - from odontoclast resorption 2. Loss of Bone - through remodeling 3. Increased Force On Primary Tooth - support decreases and tissues must support comparatively increased masticatory forces
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