There are various types of bone grafts, all of which are designed to build up the bone that is missing. The ridge or socket preservation graft is a type of graft that is done when a patient does not have adequate jawbone for an implant. It is used to fill in the hole from an extraction site, so there is no vacancy around the implant, which would cause it to fail.
A sinus lift is for when the patient has suffered too much bone loss for an implant to be placed without building up the bone. A sinus lift is used in smaller areas of a few teeth, in the upper jaw, below the sinus cavity. Thirdly, a sinus graft or block graft is for when there is a lot of bone loss in the sinus area, front of the mouth, or even in the lower jawline. A block of bone material (consisting of artificial bone, cadaver bone, or bovine bone) is screwed into place with small titanium screws. After the bone has healed and integrated into the natural bone, it serves well to hold implants. If a patient is in need of a bone graft, the type of graft, and the material used would be determined by your dentist.