Post-extraction the alveolus undergoes modelling which reduces height and width. This may present a problem for subsequent crown and bridge or implant therapy. Ridge preservation is the use of grafts and/or membranes to try to minimize the loss of the alveolar ridge. Extraction sockets have been filled with autogenous, allogenic and alloplastic materials. Membranes or soft tissue were used to contain the graft. More recently biodegradable sponges and materials coated in growth factors have been tested. Studies have primarily looked at either maintenance of vertical and horizontal dimensions or the healing of the socket and how much of the graft material is incorporated into the newly formed bone. Irrespective of method or materials, there seems to be some maintenance of the alveolus. Bone fill seems to occur in preserved extraction sockets, but in most cases with a high percentage of residual graft particles. In general, there is a lack of evidence to show that ridge preservation aids in correct 3-D implant placement, maintains hard and soft tissue volume over a prolonged period of time or for success and survival of implants placed into ridge preserved sockets. Still the most effective way to maintain ridge volume is to keep the natural tooth.