Bone grafting is a surgical procedure to replace missing bone with material from a patient's own body, however, natural and synthetic substitutes are also used. This procedure is performed with the aim of stimulating new bone formation in the body.
"Auto-graft" means tissue implanted from one part of the body to another in the same individual. Traditionally, surgeons have used a patient's own bone, but harvesting this bone requires an additional surgical procedure. There are several drawbacks to this approach. First, your body does not offer an unlimited supply of bone, as there is only so much bone the surgeon can remove without creating another problem. Second, the harvesting procedure can be painful and more severe than the bone grafting surgery.
These disadvantages of auto-grafts have led the way for the use of natural or synthetic materials from sources outside of the body, known as "bone graft substitutes."