Missing Teeth / Edentulism
The term edentulism refers to permanent teeth which are lost from a place that once had them. An edentulous site is a position in the mouth previously occupied by a tooth. An edentulous area is a region from which multiple teeth have been lost. Total edentulism is the loss of all teeth.
Edentulism is contrasted with anodontia, which is a term for congenital absence of all of the teeth (i.e. the patient never gets teeth); and hypodontia, which is a term for congenital absence of some of the teeth. Hypodontia is also called partial anodontia, which is something of a misnomer. While hypodontia is common, anodontia is rare, and is usually associated with a condition called hypohydrotic ectodermal dysplasia.
Reasons for replacing missing teeth include: to prevent the remaining teeth from moving; to prevent the remaining teeth from becoming overloaded; to preserve the ability to chew normally and maintain proper nutrition; to preserve the tooth bearing (alveolar) bone; to support the cheeks and lips; to restore the appearance of the smile.