Changes

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|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|radiographs]] as abnormal [[Enamel Organ#Root|root]] formation is not uncommon with these teeth.  

'''Enamel dysplasia''' results from abnormal enamel formation on the crown of the tooth. This occurs when an injury or other disruption occurs during the [[Tooth Development|formation of enamel]]. All enamel formation occurs prior to [[Tooth Development#Eruption|eruption of the tooth]]. The crown formation of the permanent/secondary teeth occurs from the second week postpartum to the age of three months. The crown of the first permanent mandibular

'''Enamel dysplasia''' results from abnormal enamel formation on the crown of the tooth. This occurs when an injury or other disruption occurs during the [[Tooth Development|formation of enamel]]. All enamel formation occurs prior to [[Tooth Development#Eruption|eruption of the tooth]]. The crown formation of the permanent/secondary teeth occurs from the second week postpartum to the age of three months. The crown of the first permanent mandibular

molar, however, begins to undergo development and mineralisation prior to birth. Only those areas of the crown undergoing active formation at the time of the injury will be affected, giving the banded appearance sometimes seen. <font color="red">(pic11generalisedED)</font color> If only a small area of dysplasia is seen this is usually asscociated with localized trauma to the developing crown.  <font color="red">(pic12localisedED)</font color> <br>

molar, however, begins to undergo development and mineralisation prior to birth. Only those areas of the crown undergoing active formation at the time of the injury will be affected, giving the banded appearance sometimes seen. <font color="red">(pic11generalisedED)</font color> If only a small area of dysplasia is seen this is usually asscociated with localized trauma to the developing crown.  <font color="red">(pic12localisedED)</font color> <br>

Defective enamel, when there is not enough of it but it is of normal hardness, is known as [[Enamel Hypoplasia|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, when there is not enough of it but it is of normal hardness, is known as [[Enamel Hypoplasia|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 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 results from a febrile reaction, and, in rare cases hypocalcaemia, excessive fluoride ingestion and

'''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 results 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]].

nutritional deficiencies. There have been case reports of dysplasia associated with congenital renal disease.

confirmed histologically that Amelogenesis imperfecta is a common cause of discoloured teeth in the standard poodles (Mannerfelt, 2009). This report is the first report to describe the condition in dogs.

Clinical significance - Enamel forms the outer covering of the tooth and forms an impermeable barrier protecting the underlying tooth components. If enamel is poorly formed or missing completely the underlying dentine is exposed, resulting in sensitivity and severe pain in some cases. The sensitivity is caused by changes in the hydrostatic pressure in the dentinal tubules which contain odontoblast processes which trigger a pain pathway. In mild cases, the pulp will often respond to the stimulation by laying down more dentine, reparative (tertiary) dentine, which obliterates the dentinal tubule space. In severe cases of dysplasia, the pulp can become chronically inflamed and undergo irreversible pulpitis as a result of bacterial ingression through the exposed dentinal tubules; periapical disease then develops. Pic13-eneamel dysplasiaRad

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 the standard poodles <font color="red">(Mannerfelt, 2009)</font color> . This report is the first report to describe the condition in dogs.

Dens in dente – tooth within a tooth

This occurs when the tooth bud folds in on itself resulting in enamel, 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. (Pic14-rad)

Enamel forms the outer covering of the tooth and forms an impermeable barrier protecting the underlying tooth components. If enamel is poorly formed or missing completely the underlying dentine is exposed, resulting in sensitivity and severe pain in some cases. The sensitivity is caused by changes in the hydrostatic pressure in the dentinal tubules which contain odontoblast processes which trigger a pain pathway. In mild cases, the pulp will often respond to the stimulation by laying down more dentine, reparative (tertiary) dentine, which obliterates the dentinal tubule space. In severe cases of dysplasia, the pulp can become chronically inflamed and undergo irreversible pulpitis as a result of bacterial ingression through the exposed dentinal tubules; periapical disease then develops. <font color="red">Pic13-eneamel dysplasiaRad</font color>

Abnormalities with the roots  

Extra roots

 

Dilacerated roots (misshapen roots).

 

 

==Abnormalities with the roots ==

* Extra roots

* Dilacerated roots (misshapen roots)