Extraction of Teeth - done atraumatically to avoid the loss of bone. Bone is needed for future support of dental restorations - bridges, partials and complete dentures. Also bone is preserved in case implant restorations are desired. In some cases bone grafting is done immediately after tooth removal to preserve and add to the volume of bone for future implants.
For addiontal information, visit the American Association of Oral and Maxillofacial Surgery site.