Difference between revisions of "Tooth Development"

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==Introduction==
 
==Introduction==
[[Image:Gaboon Viper Skull.jpg|thumb|right|150px|Gaboon Viper - Copyright RVC]]
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[[Image:Gaboon Viper Skull.jpg|thumb|right|250px|Gaboon Viper - Copyright RVC]]
Teeth develop differently in different regions of the mouth in most species, a process called heterodonty. In some animals teeth develop identically in different regions of the mouth, a process called homodonty. Different species will have varying numbers of teeth and different shapes depending largely on diet.
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Teeth develop differently in different regions of the mouth in most species, a process called '''heterodonty'''. In some animals, teeth develop identically in different regions of the mouth, a process called '''homodonty'''. Different species will have varying numbers of teeth and different shapes depending largely on their diet. Not all species possess teeth and there is huge variation in dental formulae between the species that have teeth. Teeth are mainly used for [[Mastication|mastication]] - chewing and grinding food particles, but are also used for seizing prey and tearing. The '''occlusion surface''' is where opposing teeth touch. The contact surface is where adjacent teeth touch.
 
 
Not all species possess teeth and there is huge variation in dental formulae between the species that have teeth.
 
 
 
Teeth are mainly used for [[Mastication|mastication]] - chewing and grinding food particles, but are also used for seizing prey and tearing.
 
 
 
The occlusion surface is where opposing teeth touch. The contact surface is where adjacent teeth touch.
 
  
 
==Tooth Development==
 
==Tooth Development==
  
[[Image:Tooth Development Histology.jpg|thumb|right|150px|Tooth Development Histology - Copyright RVC 2008]]
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[[Image:Tooth Development Histology.jpg|thumb|right|250px|Tooth Development Histology - Copyright RVC 2008]]
1. Focal thickening of oral epithelium on medial aspect of the [[Gingiva Introduction#Labiogingival groove|labiogingival groove]] forms the dental lamina
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Tooth development occurs in the following stages;
 
 
2. Mesenchyme under each laminae condenses
 
 
 
3. Dental lamina invaginates to form the dental bud
 
 
 
4. Dental bud expands and branches to become the enamel organ
 
 
 
5. Enamel organ surrounds the neural crest cell derived dental papilla
 
 
 
6. Combination of enamel organ and dental papillae forms the deciduous tooth
 
 
 
7. Small mass of cells bud off the dental lamina forming the primordium of the permanent tooth which continues development
 
 
 
8. Inner cell layer of enamel organ (from oral epithelium) differentiates into [[Ameloblasts|ameloblasts]]
 
 
 
9. Neighbouring cells in dental papillae (from neural crest cells) differentiate into [[Odontoblasts - Anatomy & Physiology|odontoblasts]]
 
 
 
10. Dentine surrounds [[Pulp - Anatomy & Physiology|pulp]] to produce [[Root - Anatomy & Physiology|root]] of tooth
 
 
 
11. Epithelial cells near the distal tooth form [[Cementoblasts - Anatomy & Physiology|cementoblasts]], secreting [[Cementum - Anatomy & Physiology|cementum]] around the tooth [[Root - Anatomy & Physiology|root]]
 
 
 
*Reciprocal inductive interaction between the oral epithelium and mesenchyme precursors
 
 
 
*Mesenchyme forms the tooth. It has labile differentiative properties but stabile morphogenic properties.
 
 
 
*Tooth formation starts at the [[Crown|crown]] and progresses towards the [[Root - Anatomy & Physiology|root]]
 
 
 
*Tooth does not aquire full length until the [[Crown|crown]] has emerged
 
 
 
*Tooth growth is appositional
 
 
 
==Eruption==
 
 
 
===Deciduous Tooth===
 
  
*Occurs after the [[Crown|crown]] has fully formed (prior to complete [[Root - Anatomy & Physiology|root]] formation)
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1. Focal thickening of oral epithelium on the medial aspect of the [[Gingiva#Labiogingival groove|labiogingival groove]] forms the dental lamina.
  
*Provides the space required for [[Root - Anatomy & Physiology|root]] completion
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2. The mesenchyme under each laminae condenses.
  
*Epithelial covering is continuous with gums after eruption
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3. The dental lamina invaginates to form the dental bud.
  
*Erosion (wear) removes epithelium
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4. The dental bud expands and branches to become the enamel organ.
  
*'Toothless' gene stops eruption
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5. The enamel organ surrounds the neural crest cell derived, dental papilla.
  
[[Image:Tooth Radiograph.jpg|thumb|right|150px|Tooth Radiograph - Copyright Nottingham 2008]]
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6. The combination of the enamel organ and dental papillae forms the deciduous tooth.
===Permanent Tooth===
 
  
*Migrates into socket of deciduous tooth on lingual side
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7. Small mass of cells bud off the dental lamina forming the primordium of the permanent tooth which continues development.
  
*Increases pressure on deciduous tooth by increased growth
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8. The inner cell layer of enamel organ (from oral epithelium) differentiates into [[Tooth - Anatomy & Physiology#Ameloblasts|ameloblasts]].
  
*Resorption of deciduous tooth root leads to loosening of deciduous tooth
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9. Neighbouring cells in the dental papillae (from neural crest cells) differentiate into [[Tooth - Anatomy & Physiology#Odontoblasts|odontoblasts]].
  
*Shedding of deciduous tooth
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10. Dentine surrounds [[Tooth - Anatomy & Physiology#Pulp|pulp]] to produce the [[Tooth - Anatomy & Physiology#Root|root]] of the tooth.
  
*Permanent tooth replaces deciduous tooth
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11. Epithelial cells near the distal tooth form [[Tooth - Anatomy & Physiology#Cementoblasts|cementoblasts]], secreting [[Tooth - Anatomy & Physiology#Cementum|cementum]] around the tooth [[Tooth - Anatomy & Physiology#Root|root]].
  
*Premature loss of deciduous tooth leads to disorganised (non-occluding) permanent teeth
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There is a reciprocal inductive interaction between the oral epithelium and mesenchyme precursors. The mesenchyme forms the tooth, it has labile differentiative properties but stable morphogenic properties. Tooth formation starts at the [[Tooth - Anatomy & Physiology#Crown|crown]] and progresses towards the [[Tooth - Anatomy & Physiology#Root|root]]. The tooth does not acquire full length until the crown has emerged. Tooth growth is appositional.
  
==Test yourself with the Teeth and Gingiva Flashcards==
 
  
[[Oral Cavity - Anatomy & Physiology - Flashcards#Teeth & Gingiva Flashcards|Teeth & Gingiva Flashcards]]
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{{Learning
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|flashcards= [[Teeth and Gingiva Flashcards]]
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|powerpoints= [[Oral Cavity Histology resource|Histology of the oral cavity, see part 2 for developing teeth]]
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}}
  
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{{OpenPages}}
 
[[Category:Teeth - Anatomy & Physiology]]
 
[[Category:Teeth - Anatomy & Physiology]]

Latest revision as of 13:19, 2 November 2014


Introduction

Gaboon Viper - Copyright RVC

Teeth develop differently in different regions of the mouth in most species, a process called heterodonty. In some animals, teeth develop identically in different regions of the mouth, a process called homodonty. Different species will have varying numbers of teeth and different shapes depending largely on their diet. Not all species possess teeth and there is huge variation in dental formulae between the species that have teeth. Teeth are mainly used for mastication - chewing and grinding food particles, but are also used for seizing prey and tearing. The occlusion surface is where opposing teeth touch. The contact surface is where adjacent teeth touch.

Tooth Development

Tooth Development Histology - Copyright RVC 2008

Tooth development occurs in the following stages;

1. Focal thickening of oral epithelium on the medial aspect of the labiogingival groove forms the dental lamina.

2. The mesenchyme under each laminae condenses.

3. The dental lamina invaginates to form the dental bud.

4. The dental bud expands and branches to become the enamel organ.

5. The enamel organ surrounds the neural crest cell derived, dental papilla.

6. The combination of the enamel organ and dental papillae forms the deciduous tooth.

7. Small mass of cells bud off the dental lamina forming the primordium of the permanent tooth which continues development.

8. The inner cell layer of enamel organ (from oral epithelium) differentiates into ameloblasts.

9. Neighbouring cells in the dental papillae (from neural crest cells) differentiate into odontoblasts.

10. Dentine surrounds pulp to produce the root of the tooth.

11. Epithelial cells near the distal tooth form cementoblasts, secreting cementum around the tooth root.

There is a reciprocal inductive interaction between the oral epithelium and mesenchyme precursors. The mesenchyme forms the tooth, it has labile differentiative properties but stable morphogenic properties. Tooth formation starts at the crown and progresses towards the root. The tooth does not acquire full length until the crown has emerged. Tooth growth is appositional.



Tooth Development Learning Resources
FlashcardsFlashcards logo.png
Flashcards
Test your knowledge using flashcard type questions
Teeth and Gingiva Flashcards
Category:Histology PowerPointsPowerPoint.png
PowerPoint
Selection of relevant PowerPoint tutorials
Histology of the oral cavity, see part 2 for developing teeth



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