Major and Minor Bone Grafting

Over a period of time, the jawbone associated with missing teeth atrophies or is reabsorbed. This often leaves a condition in which there is poor quality and quantity of bone suitable for placement of dental implants. In these situations, most patients are not candidates for placement of dental implants. 

Today, we have the ability to grow bone where needed. This not only gives us the opportunity to place implants of proper length and width, it also gives us a chance to restore functionality and esthetic appearance.

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 (cadaveric bone) or your own bone is taken from the jaw, hip or tibia (below the knee.)   The success rates with the cadaveric bone are very high and have diminished the need for taking donor bone from the patient.  Many patients today can attain excellent bone augmentation via tissue bank bone which undergoes rigorous screenings to ensure that the process is sterile and infection free.  There has not been a documented case of a transmissible disease with the cadaveric (tissue bank) bone used. In addition, special resorbable membranes may be utilized that dissolve under the gum, 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 defects of the jaws. These defects may arise as a result of traumatic injuries, tumor surgery, or congenital defects. Large defects are repaired using the patient’s own bone. This bone is harvested from a number of different sites depending on the size of the defect. The skull (cranium), hip (iliac crest), and lateral knee (tibia), are common donor sites. It may take up to 6 months before the donor bone integrates (bonds to) to the patient's bone.   These procedures are routinely performed in an operating room and require a hospital stay.

Minor Bone Grafting

The overwhelming majority of bone graft procedures for implants are categorized as minor bone grafting procedures.  These procedures require only a 3 month period for the donor bone to integrate (bond with the patient's bone) prior to implant placement; unlike major bone grafting which may take up to 6months.   A cadaveric bone graft is usually performed at the time of tooth extraction to prevent bone loss and gross atrophy of the jaw bone.  There may be up to 30% bone loss in the upper jaw within 6 months if a tooth is extracted without the placement of a bone graft.  The bone graft maintains the shape of the jaw to optimize the success of subsequent implant placement and maintain ideal esthetics.  There may be facial rhytids (wrinkling) of the skin due to tooth and bone loss.

Sinus Lift Procedure

The maxillary sinuses are behind your cheeks and on top of the upper teeth. Sinuses are like empty rooms that have nothing in them. 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 need bone to hold them in place. When the sinus wall is very thin, it is impossible to place dental implants in this bone.

There is a solution and it’s called a sinus graft or sinus lift graft. The dental implant surgeon enters the sinus from where the upper teeth used to be. The sinus membrane is then lifted upward and donor bone is inserted into the floor of the sinus. Keep in mind that the floor of the sinus is the roof of the upper jaw. After about 6 months of healing, the bone becomes part of the patient’s jaw and dental implants can be inserted and stabilized in this new sinus bone.

The sinus graft makes it possible for many patients to have dental implants when years ago there was no other option other than wearing loose dentures.

If enough bone between the upper jaw ridge and the bottom of the sinus is available to stabilize the implant well, sinus augmentations and implant placement can sometimes be performed as a single procedure. If not enough bone is available, the Sinus Augmentation will have to be performed first, then the graft will have to mature for several months, depending upon the type of graft material used. Once the graft has matured, the implants can be placed.