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==Introduction==
[[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 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.
==Tooth Development==
[[Image:Tooth Development Histology.jpg|thumb|right|250px|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 [[Gingiva#Labiogingival groove|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 [[Enamel Organ#Ameloblasts|ameloblasts]].
9. Neighbouring cells in the dental papillae (from neural crest cells) differentiate into [[Enamel Organ#Odontoblasts|odontoblasts]].
10. Dentine surrounds [[Enamel Organ#Pulp|pulp]] to produce the [[Enamel Organ#Root|root]] of the tooth.
11. Epithelial cells near the distal tooth form [[Enamel Organ#Cementoblasts|cementoblasts]], secreting [[Enamel Organ#Cementum|cementum]] around the tooth [[Enamel Organ#Root|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 [[Enamel Organ#Crown|crown]] and progresses towards the [[Enamel Organ#Root|root]]. The tooth does not acquire full length until the crown has emerged. Tooth growth is appositional.
==Eruption==
===Deciduous Tooth===
Eruption occurs after the [[Enamel Organ#Crown|crown]] has fully formed (prior to complete [[Enamel Organ#Root|root]] formation). It provides the space required for [[Enamel Organ#Root|root]] completion. The epithelial covering is continuous with gums after eruption. Erosion (wear) removes the epithelium. The 'toothless' gene stops eruption.
[[Image:Tooth Radiograph.jpg|thumb|right|250px|Tooth Radiograph - Copyright Nottingham 2008]]
===Permanent Tooth===
The tooth migrates into the socket of the deciduous tooth on the lingual side. It increases the pressure on the deciduous tooth by increased growth. Resorption of the deciduous tooth root leads to its loosening. The deciduous tooth then sheds and the permanent tooth replaces it. Premature loss of the deciduous tooth leads to disorganised (non-occluding) permanent teeth.
==Enlaces==
Click here for the [[Cavidad Oral - Anatomía & Fisiología - Flashcards#Teeth & Gingiva Flashcards|teeth & gingiva flashcards]].
[[Categoría:Dientes - Anatomía & Fisiología]]
[[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 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.
==Tooth Development==
[[Image:Tooth Development Histology.jpg|thumb|right|250px|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 [[Gingiva#Labiogingival groove|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 [[Enamel Organ#Ameloblasts|ameloblasts]].
9. Neighbouring cells in the dental papillae (from neural crest cells) differentiate into [[Enamel Organ#Odontoblasts|odontoblasts]].
10. Dentine surrounds [[Enamel Organ#Pulp|pulp]] to produce the [[Enamel Organ#Root|root]] of the tooth.
11. Epithelial cells near the distal tooth form [[Enamel Organ#Cementoblasts|cementoblasts]], secreting [[Enamel Organ#Cementum|cementum]] around the tooth [[Enamel Organ#Root|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 [[Enamel Organ#Crown|crown]] and progresses towards the [[Enamel Organ#Root|root]]. The tooth does not acquire full length until the crown has emerged. Tooth growth is appositional.
==Eruption==
===Deciduous Tooth===
Eruption occurs after the [[Enamel Organ#Crown|crown]] has fully formed (prior to complete [[Enamel Organ#Root|root]] formation). It provides the space required for [[Enamel Organ#Root|root]] completion. The epithelial covering is continuous with gums after eruption. Erosion (wear) removes the epithelium. The 'toothless' gene stops eruption.
[[Image:Tooth Radiograph.jpg|thumb|right|250px|Tooth Radiograph - Copyright Nottingham 2008]]
===Permanent Tooth===
The tooth migrates into the socket of the deciduous tooth on the lingual side. It increases the pressure on the deciduous tooth by increased growth. Resorption of the deciduous tooth root leads to its loosening. The deciduous tooth then sheds and the permanent tooth replaces it. Premature loss of the deciduous tooth leads to disorganised (non-occluding) permanent teeth.
==Enlaces==
Click here for the [[Cavidad Oral - Anatomía & Fisiología - Flashcards#Teeth & Gingiva Flashcards|teeth & gingiva flashcards]].
[[Categoría:Dientes - Anatomía & Fisiología]]