Bone Preservation and Bone Augmentation are the two main purposes of Hard Tissue (Bone) Grafting.
There are several different types of bone grafts that can be performed, the most common being a Socket Graft, which is when a bone graft is placed at the time of tooth extraction into the existing tooth socket to help preserve the bone volume until an implant can be placed at a later date. This is the least invasive, as well as the least expensive bone graft.
A Ridge Augmentation is performed when your bony jaw ridge has been significantly reduced in size due to missing teeth for an extended period of time.
There are instances prior to placing an upper implant in which the maxillary sinus may be lower than ideal for placing a traditionally sized implant. A Crestal Sinus Lift is performed in order to raise the bone just below the sinus 2-4 millimeters to allow enough space for implant placement.
When upper back teeth have been missing for an extended period of time, the maxillary sinus may droop all the way down to the level of your bony ridge, allowing no room for any sized dental implant to be placed. With a Lateral Wall Sinus Lift, the sinus membrane itself is lifted up to allow bone to be grafted beneath. The bone is allowed to mineralize for several months, upon which there is adequate room for implants to be placed.