Amelogenesis imperfecta

Amelogenesis imperfecta is a hereditary defect of tooth and is not associated with any other generalized defects.

Since it is absolutely an ectodermal disorder, the mesodermal structures of the tooth like; dentin and pulp, etc. are always normal in this disease.

Generally amelogenesis imperfecta is of three types:

• Hypoplastic type
• Hypocalcification type
• Hypomaturation type.

Hypoplastic type: The hypoplastic type of amelogenesis imperfecta occurs if the disease affects the enamel during its formative stage, so that, the enamel matrix could not be formed.

Clinically, the teeth with this defect will show complete lack of enamel formation or a very thin layer of enamel on the newly erupted tooth.

Hypocalcification type: In this type of amelogenesis imperfecta, the disease affects the enamel during the stage of its calcification.

Clinically, the teeth will have a normal thickness of enamel, but it is very soft and can easily be removed by the dental explorers.

Hypomaturation type: In this case, the disease affects during the mineralization or maturation process, which results in the formation of a hypomineraiized enamel.

Clinically, the enamel is of normal thickness, but it can be pierced by an explorer point under firm pressure and is lost easily by chipping away during mastication.

Clinical Features
Both the deciduous as well as the permanent dentition can be affected by amelogenesis imperfecta. The color of the teeth is mostly chalky white, but it can be yellow or even dark-brown.

The contact points between teeth are mostly open and occlusal surfaces and incisal edges are severely abraided.

The tooth surface may have a cheesy consistency, and there may be presence of numerous wrinkles àr grooves also. However, the teeth in this disease do not show higher caries incidence.

Radiological Features
Radiographs of amelogenesis imperfecta show total absence of enamel from the tooth surface in many cases and whenever present, it is mostly seen on the tip of the cusps and on the proximal areas.

The radiodensity of enamel in this disease is much less and is very close to that of the dentin.

Histopathology
Histological features of amelogenesis imperfecta shows hypoplastic type shows lack of differentiation of the ameloblast cells, with no matrix formation.

The hypocalcification type shows defective matrix structure and abnormal mineral deposition. The hypomaturation type shows alteration in the enamel rod and rod-sheath structures.

Treatment
There is no treatment available in amelogenesis imperfecta and composite veneering can be done to improve the appearance.