Changes

==Introduction==

==Introduction==

Problems with [[Tooth Development|normal tooth development]] fall into three main categories:

Problems with [[Tooth Development|normal tooth development]] fall into three main categories:

==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.

'''Generalised enamel dysplasia''' - Historically, the most common cause of enamel dysplasia was [[Distemper|distemper virus]] - the virus caused a febrile reaction which affected the developing tooth, but it is also an epitheliotropic virus, affecting developing epithelium, from which ameloblasts originate. Virus particles have been demonstrated in the actual ameloblasts. Other causes of generalised enamel dysplasia usually result from a febrile reaction, and, in rare cases [[Hypocalcaemia|hypocalcaemia]], excessive fluoride ingestion and nutritional deficiencies. There have been case reports of dysplasia associated with [[:Category: Kidney - Developmental Pathology|congenital renal disease]].

'''Generalised enamel dysplasia''' - Historically, the most common cause of enamel dysplasia was [[Distemper|distemper virus]] - the virus caused a febrile reaction which affected the developing tooth, but it is also an epitheliotropic virus, affecting developing epithelium, from which ameloblasts originate. Virus particles have been demonstrated in the actual ameloblasts. Other causes of generalised enamel dysplasia usually result from a febrile reaction, and, in rare cases [[Hypocalcaemia|hypocalcaemia]], excessive fluoride ingestion and nutritional deficiencies. There have been case reports of dysplasia associated with [[:Category: Kidney - Developmental Pathology|congenital renal disease]].

'''''Amelogenesis imperfecta''''' - A term often incorrectly used in veterinary dentistry to mean any condition resulting in enamel dysplasia. ''Amelogenesis imperfecta'' is a hereditary condition of humans in which the genes that encode for enamel proteins (amelogenin, enamelin and others) are mutated. Most cases are inherited as an autosomal-dominant trait. The condition affects both the primary and secondary dentition. One study of enamel defects in standard poodles in Sweden confirmed histologically that ''Amelogenesis imperfecta'' is a common cause of discoloured teeth in standard poodles <font color="red">(Mannerfelt, 2009)</font color>. This report is the first report to describe the condition in dogs.

'''''Amelogenesis imperfecta''''' - A term often incorrectly used in veterinary dentistry to mean any condition resulting in enamel dysplasia. ''Amelogenesis imperfecta'' is a hereditary condition of humans in which the genes that encode for enamel proteins (amelogenin, enamelin and others) are mutated. Most cases are inherited as an autosomal-dominant trait. The condition affects both the primary and secondary dentition. One study of enamel defects in standard poodles in Sweden confirmed histologically that ''Amelogenesis imperfecta'' is a common cause of discoloured teeth in standard poodles <ref>Mannerfelt, T. (2009) '''Enamel defects in standard poodle dogs in Sweden. '''''Journal of Veterinary Dentistry ''26(4).</ref>. This report is the first report to describe the condition in dogs.

====Clinical Significance====

====Clinical Significance====

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.   

<center><gallery widths=250px heights=180px mode="traditional">

<center><gallery widths=250px heights=180px mode="traditional">

File:Extra tooth root 2.jpg|Extra root

File:Extra tooth root 2.jpg|Extra root

</gallery></center>

</gallery></center>

{{Learning

{{Learning

|flashcards = [[Veterinary Dentistry Q&A 13]]

|flashcards = [[Veterinary Dentistry Q&A 13]]

}}

}}

[[Category:Developmental Dental Conditions]]

[[Category:Developmental Dental Conditions]]

[[Category:To Do - Dentistry questions]]

[[Category:Waltham reviewed]]

[[Category:To Do - Mars Check]]