Anodontia is an extremely rare genetic condition in which the patient is missing all of his teeth. They simply never grow in, and although it can affect baby teeth, it typically only affects permanent teeth.
According to the National Organization for Rare Disorders (NORD), a child suffering from anodontia will most often never grow any more teeth after losing the primary set. However, dentists more frequently see cases of hypodontia, the nonexistence of between one and six teeth; or oligodontia, the absence of more than six, but not all.
Little can be done in cases like this beyond implants or dentures, but it's important to take certain steps early for the purposes of a child's good oral health, ability to eat, speak and breathe normally, jaw and facial structure and ultimately self-esteem. Kids with this condition often also have ectodermal dysplastic syndrome, which is a group of more than 150 genetic disorders with varying symptoms.