Congenitally total anodontia is congenital absence of all or most teeth, and also is a performance of ectodermal dysplasia syndrome. It is a kind of genetic disease, which represents complex group of diseases characterized by various defects in teeth, hair, skin, and so on, which is divided into two categories as ectodermal dysplasia anhidrotic（EDA） or called hypohidrotic ectodermal dysplasia and hidrotic ectodermal dysplasia. In addition to teeth, hair, skin and other structural abnormalities, patients of EDA are lack of sweat glands, who can not regulate body temperature, hidrotic type have normal sweat glands.
