Hypodontia (the common dental term) describes a situation when fewer than 6 permanent teeth are missing, the term Oligodontia is used when more than 6 permanent teeth are missing (they were never formed). The most common missing teeth are the third molars (otherwise known as the Wisdom Teeth), followed by the premolars and the lateral incisors. Although it is not uncommon to have one missing tooth, patients with multiple missing teeth generally have a strong genetic component and it has been linked to conditions such as Ectodermal Dysplasia and several syndromes. Because early recognition aids in proper treatment, your dentist will refer you to specialists (orthodontist, oral surgeons, etc) that will determine which options suit you best to replace the missing teeth.