In dentistry, hypodontia is the condition of naturally having fewer than the regular number of teeth. In Caucasians, the most commonly missing teeth are the third molars (25-35%), the upper lateral incisors (2%) or the lower second premolars (3%) The congenital absence of all teeth is called anodontia. Hypodontia is often familial, or associated with ectodermal dysplasia or Down syndrome.