Monday, October 17, 2011

Amelogenesis Imperfecta and Enamel Hypoplasia

> The Amelogenesis imperfecta comprises a group of complicated conditions that show abnormal development in the structure of enamel in the absence of a systemic change.

Three resistant structures in the tooth: the enamel, dentin and cementum have different characteristics as to their chemical composition, its physical and chemical factors, their origin, function and pathology. The enamel, or outer covering of the tooth, is the substance harder on the body, is found only in the crown, coating completely and protecting the dentin of external exposure. The tooth enamel is composed of about 96% of organic material, and the remaining 4% are composed of organic matrix and water. These dental disorders can be manifested as abnormalities of shape, number, eruption and exfoliation, or structure.

There are two basic types of enamel hypoplasia:
1) A type-hereditary amelogenesis imperfect.
2) A type caused by environmental factors.

The amelogenesis imperfecta is a group of hereditary enamel defects not associated with any other defects generalized. A disorder exclusively ectoderm, as the mesoderm components of the teeth are basically normal.

Among the imperfect amelogenesis find:
1) Amelogenesis imperfecta, hypoplastic enamel thickness is smaller than normal, with horizontal cracks and depressions.
2) hypoplastic Amelogenesis impereita depressions with autosomal-dominant.
3) Amelogenesis imperfecta local hypoplastic autosomal domiante.
4) Dominant Amelogenesis outossomica tooth surface smooth.
5) Amelogenesis imperfecta hipoplatica with rough-autosomal dominant.
6) Amelogenesis imperfecta hipoplatica X-linked
8) Amelogenesis imperfecta hipomaturativa
9) Amelogenesis imperfecta, hypoplastic hipomaturativa taurodontia with autosomal dominant
10) Amelogenesis imperfecta hipomaturativa X-linked
11) Amelogenesis imperfecta, pigmented autosomal recessive.

Several different factors, causing damage to the ameloblasts:
1 - Nutritional deficiencies such as vitamins A, C and D.
2 - Exantemoticas diseases e.g. measles, chicken pox, scarlet fever.
3 - Congenital syphilis.
4 – Hypocalcaemia.
5 - Trauma at birth, prematurity.
6 - Local infection or trauma.
7 - Ingestion of chemicals.
8 - Idiopathic.

Dental enamel hypoplasia produced by local causes develop a special type of anomaly known as tooth Turner. Turner's tooth in addition to hypoplasia, has misshapen crown or different structure of the defective enamel to change the shape of the root.