Over a period of time the jawbone associated with missing teeth atrophies or is resorbed. 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.
Bone Graft Procedures
Bone grafting can repair dental implant sites with adequate bone structure due to previous extractions, gum disease or injuries. The bone is either obtained from tissue bank or your own bone is taken from 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 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 patients 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. These procedures are routinely performed in an operating room and require a hospital stay.
Sinus Lift Procedure
The maxillary sinuses are behind your cheeks and above the upper teeth. Some of the roots of the natural upper teeth may 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 is called a sinus graft or sinus lift.
The dental implant surgeon enters the sinus from where the upper teeth used to be. The sinus membrane is then lifted upward and the donor bone is inserted into the floor of the sinus.
After several months of healing, the bone becomes part of the patients jaw and a dental implant 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 were 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 dental implants placement can sometimes be performed as a single procedure. If not enough bone is available, the sinus augmentation will have to be performed first and allowed to mature for several months, depending upon the type of graft material used. Once the graft has matured, the dental implants can be placed.
In severe cases, the ridge has been resorbed and a bone graft is placed to increase ridge height and/or width. This is a technique used to restore the lost bone dimension when the jaw ridge is too thin to place conventional implants. In this procedure, the boney ridge of the jaw is literally expanded by mechanical means. Bone graft material can be placed and allowed to mature for a few months before placing the implant.
Ridge Preservation refers to a specific application of bone grafting that attempts to prevent the resorption of bone that normally follows the removal of a tooth. At the time of tooth removal, the resulting socket is filled with bone material and covered with a protective dressing. Our doctors typically use processed cow or human donor bone for this purpose, sometimes mixing it with a small amount of bone obtained from a neighboring area of the patients own jaw. Filling the socket with bone in this manner dramatically delays the normal bone resorption process that would occur at an extraction site. It also hastens the process of bone maturation at the site, thus allowing the placement of a dental implant sooner that would be possible if the socket was left to heal without the benefit of the added bone. This procedure is very successful in preserving the ridge of the bone that is necessary for implant placement-hence the term “ridge preservation” Postoperative recovery following this procedure is usually no more complicated than that following removal of a tooth without ridge preservation.