How Bone Grafting Works

Autogenous Bone Grafts:

Autogenous bone grafts utilize your own bone, taken from somewhere else in the body. The bone is typically harvested from the chin, jaw, lower leg bone, hip, or the skull. Autogenous bone grafts are advantageous in that the graft contains living cellular elements that enhance bone growth.

However, one downside to the autograft is that it requires a second procedure to harvest bone from elsewhere in the body. Depending on your condition, a second procedure may not be in your best interest.

Allogenic Bone:

Allogenic bone, or allograft, is bone harvested from a cadaver, then processed using a freeze-dry method to extract the water via a vacuum. Unlike autogenous bone, allogenic bone cannot produce new bone on its own. Rather, it serves as a framework or scaffold over which bone from the surrounding bony walls can grow to fill the defect or void.

Xenogenic Bone:

Xenogenic bone is harvested from another species, usually a cow. The bone is processed at very high temperatures to avoid the potential for immune rejection and contamination. Like allogenic grafts, xenogenic grafts serve as a framework for bone or scaffold for bone from the surrounding area to grow and fill the void.

Both allogenic and xenogenic bone grafts are advantageous in that they do not require a second procedure to harvest your own bone.

Types of Grafting Procedures

Socket Preservation

A socket preservation is a common surgical procedure often performed following a tooth extraction to help recreate the natural contour of the gums and jaw that may have been lost due to bone loss as a result of a tooth extraction, or for another reason.

The alveolar ridge is the bone that surrounds the roots of teeth. When a tooth is removed, an empty socket is left in the alveolar ridge. Usually this empty socket will heal on its own, filling with bone and tissue. Oftentimes, however, the bone in this region will atrophy and shrink in size during the healing process. This can result in loss of bone height and width at the site of the missing tooth, which will generally continue to deteriorate over time.

Restoring the original height and width of the alveolar ridge is not medically necessary, but may be required for dental implant placement, or for other aesthetic purposes. Dental implants require a foundation of bone for support, and socket preservation can to regenerate this needed bone for successful dental implant therapy.

A socket preservation is accomplished by placing bone graft material in the tooth socket following extraction of the tooth. A resorbable barrier and sutures may be used to help retain the bone grafting material in the socket during the healing process. This procedure is often done immediately following removal of the tooth, in order to avoid the need for a second procedure. Once the socket has healed, the patient can then proceed on to placement of the dental implant, usually 3 months later.

Major Bone Grafting

Bone grafting can repair implant sites with inadequate bone structure due to previous extractions, gum disease or injuries. The bone is either obtained from a tissue bank or your own bone is taken from the jaw, hip or tibia (below the knee). Sinus bone grafts are also performed to replace bone in the posterior upper jaw. In addition, special membranes may be utilized that dissolve under the gum and protect the bone graft and encourage bone regeneration. This is called guided bone regeneration or guided tissue regeneration.

Major bone grafts are typically performed to repair larger defects of the jaws. Bone grafting can be utilized to regenerate bone in sites with inadequate bone architecture due to previous extractions, gum disease, trauma, or pathology. The bone may either be obtained from a tissue bank or utilize your own bone harvested from another location, depending on the defect being reconstructed. Sinus lifts may be performed to replace bone in the posterior upper jaw. In addition, guided bone regeneration may be performed in other areas of the mouth to regenerate larger sized defects in preparation for dental implants. This may often involve special barrier membranes and components to help stabilize and protect the graft.

Sinus Lifts

The maxillary sinuses are empty, air-filled spaces in the upper jawbone located above the upper back teeth. Some of the roots of the natural upper teeth extend up into the maxillary sinuses. When these upper teeth are removed, there is often just a thin wall of bone separating the maxillary sinus and the mouth. Dental implants require an appropriate thickness of bone to anchor them in place. When the bone separating the mouth and sinuses is too thin, it is impossible to place dental implants in this bone.

The key to a successful and long-lasting dental implant is the quality and quantity of jawbone to which the implant will be attached. A sinus lift procedure is one of the most common bone grafting procedures for patients with insufficient bone in the upper jaw for dental implants. This procedure allows for regeneration of bone along the floor of the maxillary sinus above the bony ridge that anchors the teeth in the upper jaw. By stimulating bone formation in this location, dental implants can then be placed and secured in the new bone that forms.

In the most common sinus augmentation procedure, a small incision is made on the premolar or molar region to expose the jawbone. A small opening is cut into the bone, and the membrane lining the sinus is elevated upward. The underlying space between the sinus membrane and sinus floor is then filled with bone grafting material. After the bone graft is implanted, the incision is stitched up and the healing process begins. After several months of healing, the bone regeneration is complete and dental implants can be placed in this new bone.

Depending on the amount of bone that needs to be regenerated during the sinus lift, implant placement can sometimes be performed simultaneously. If not enough bone is available, the sinus lift will have to be performed first, and the graft will have to heal for several months before the implants may be placed. The sinus lift procedure makes it possible for many patients to have dental implants when years ago there was no other option.