Changes

==Abnormalities of the Crown==

==Abnormalities of the Crown==

Abnormalities of the [[Enamel Organ#Crown|crown]] may occur during development resulting in '''microdontia''' (smaller crown), '''macrodontia''' (larger crown), '''peg teeth (conically shaped teeth) as well as '''geminated crowns''' (double crown) or '''fused teeth''' (two separate tooth buds fused at the crown by [[Enamel Organ#Enamel|enamel]] and sometimes [[Enamel Organ#Dentin|dentine]]).<br>

Abnormalities of the [[Tooth - Anatomy & Physiology#Crown|crown]] may occur during development resulting in '''microdontia''' (smaller crown), '''macrodontia''' (larger crown), '''peg teeth (conically shaped teeth) as well as '''geminated crowns''' (double crown) or '''fused teeth''' (two separate tooth buds fused at the crown by [[Tooth - Anatomy & Physiology#Enamel|enamel]] and sometimes [[Tooth - Anatomy & Physiology#Dentin|dentine]]).<br>

This is clinically important from a periodontal health aspect to avoid plaque stagnation areas between overcrowded teeth. It is also important when planning extraction of an abnormal tooth to take [[Intra-Oral Radiography - Small Animal|radiographs]] as abnormal [[Enamel Organ#Root|root]] formation is not uncommon with these teeth.  

This is clinically important from a periodontal health aspect to avoid plaque stagnation areas between overcrowded teeth. It is also important when planning extraction of an abnormal tooth to take [[Intra-Oral Radiography - Small Animal|radiographs]] as abnormal [[Tooth - Anatomy & Physiology#Root|root]] formation is not uncommon with these teeth.  

===Enamel Dysplasia===

===Enamel Dysplasia===

Local factors causing enamel dysplasia mostly involve trauma. A blow to the face, a jaw fracture, a fractured deciduous tooth with pulp necrosis or a localised infection may all affect the developing permanent crown. Systemic factors usually result in many teeth being affected.

Local factors causing enamel dysplasia mostly involve trauma. A blow to the face, a jaw fracture, a fractured deciduous tooth with pulp necrosis or a localised infection may all affect the developing permanent crown. Systemic factors usually result in many teeth being affected.

'''Hypoplasia''' vs '''hypocalcification''' - During enamel formation, [[Enamel Organ#Ameloblasts|ameloblasts]]  are susceptible to various external factors that may damage or cause malfunction of the cells. <br>

'''Hypoplasia''' vs '''hypocalcification''' - During enamel formation, [[Tooth - Anatomy & Physiology#Ameloblasts|ameloblasts]]  are susceptible to various external factors that may damage or cause malfunction of the cells. <br>

Defective enamel, which is when there is not enough of it but what there is, is of normal hardness, is known as enamel hypoplasia. Damage to the actual ameloblasts has occurred resulting in areas where there is no enamel formation. Defective enamel, in which normal amounts of enamel are produced but the enamel is hypomineralised is known as enamel hypocalcification. In this defect, the enamel is softer than normal. It is often not possible to distinguish the two types on clinical appearance alone.

Defective enamel, which is when there is not enough of it but what there is, is of normal hardness, is known as enamel hypoplasia. Damage to the actual ameloblasts has occurred resulting in areas where there is no enamel formation. Defective enamel, in which normal amounts of enamel are produced but the enamel is hypomineralised is known as enamel hypocalcification. In this defect, the enamel is softer than normal. It is often not possible to distinguish the two types on clinical appearance alone.

Dens in dente - tooth within a tooth

Dens in dente - tooth within a tooth

This occurs when the tooth bud folds in on itself resulting in [[Enamel Organ#Enamel|enamel]], [[Enamel Organ#Dentin|dentine]] and pulp being produced with the tooth itself. Usually the invagination results in pulp exposure, and ultimately pulp necrosis. Often the crown has an abnormal shape but the diagnosis is made radiographically.   

This occurs when the tooth bud folds in on itself resulting in [[Tooth - Anatomy & Physiology#Enamel|enamel]], [[Tooth - Anatomy & Physiology#Dentin|dentine]] and pulp being produced with the tooth itself. Usually the invagination results in pulp exposure, and ultimately pulp necrosis. Often the crown has an abnormal shape but the diagnosis is made radiographically.   

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