In the time following a tooth extraction, the bone resorbs/atrophies due to disuse and alters the shape of the alveolar ridge. The ridge is then too thin for a dental implant to be inserted. To maintain the shape and thickness of the alveolar ridge, ridge augmentation (a bone grafting technique) is done such that the ridge is thick enough to take a dental implant. Usually ridge augmentation will not be needed if timely socket preservation and/or sinus lift are performed preemptively.