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Created page with "==Introduction== thumb|right|150px|Gaboon Viper - Copyright RVC Teeth develop differently in different regions of the mouth in most species, a pr..."
==Introduction==
[[Image:Gaboon Viper Skull.jpg|thumb|right|150px|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.
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|150px|Tooth Development Histology - Copyright RVC 2008]]
1. Focal thickening of oral epithelium on medial aspect of the [[Oral Cavity - Teeth & Gingiva - Anatomy & Physiology#Labiogingival groove|labiogingival groove]] forms the dental lamina
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)
*Provides the space required for [[Root - Anatomy & Physiology|root]] completion
*Epithelial covering is continuous with gums after eruption
*Erosion (wear) removes epithelium
*'Toothless' gene stops eruption
[[Image:Tooth Radiograph.jpg|thumb|right|150px|Tooth Radiograph - Copyright Nottingham 2008]]
===Permanent Tooth===
*Migrates into socket of deciduous tooth on lingual side
*Increases pressure on deciduous tooth by increased growth
*Resorption of deciduous tooth root leads to loosening of deciduous tooth
*Shedding of deciduous tooth
*Permanent tooth replaces deciduous tooth
*Premature loss of deciduous tooth leads to disorganised (non-occluding) permanent teeth
[[Image:Soft Histology of Enamel Organ.jpg|thumb|right|150px|Histology of Enamel Organ - Copyright RVC 2008]]
==Test yourself with the Teeth and Gingiva Flashcards==
[[Oral Cavity - Anatomy & Physiology - Flashcards#Teeth & Gingiva Flashcards|Teeth & Gingiva Flashcards]]
[[Category:Teeth - Anatomy & Physiology]]
[[Image:Gaboon Viper Skull.jpg|thumb|right|150px|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.
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|150px|Tooth Development Histology - Copyright RVC 2008]]
1. Focal thickening of oral epithelium on medial aspect of the [[Oral Cavity - Teeth & Gingiva - Anatomy & Physiology#Labiogingival groove|labiogingival groove]] forms the dental lamina
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)
*Provides the space required for [[Root - Anatomy & Physiology|root]] completion
*Epithelial covering is continuous with gums after eruption
*Erosion (wear) removes epithelium
*'Toothless' gene stops eruption
[[Image:Tooth Radiograph.jpg|thumb|right|150px|Tooth Radiograph - Copyright Nottingham 2008]]
===Permanent Tooth===
*Migrates into socket of deciduous tooth on lingual side
*Increases pressure on deciduous tooth by increased growth
*Resorption of deciduous tooth root leads to loosening of deciduous tooth
*Shedding of deciduous tooth
*Permanent tooth replaces deciduous tooth
*Premature loss of deciduous tooth leads to disorganised (non-occluding) permanent teeth
[[Image:Soft Histology of Enamel Organ.jpg|thumb|right|150px|Histology of Enamel Organ - Copyright RVC 2008]]
==Test yourself with the Teeth and Gingiva Flashcards==
[[Oral Cavity - Anatomy & Physiology - Flashcards#Teeth & Gingiva Flashcards|Teeth & Gingiva Flashcards]]
[[Category:Teeth - Anatomy & Physiology]]