Over a period of time, the jawbone in the area of 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.
Yet 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.
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 back part of the upper jaw. In addition, special membranes may be utilized that 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. 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, or a combination of bone with other bone replacement materials. Your 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. In the maxillofacial region (face and jaw bones), bone grafts can be taken from inside the mouth, in the area of the chin or wisdom tooth region or in the upper jaw behind the last tooth. When we use the patient’s own bone for repairs, we generally get the best results.
In many cases, we can use other bone replacement materials such as allograft material to implement bone grafting for dental implants. This bone is prepared from cadavers and used to promote the patients own bone to grow into the repair site. It is quite effective and very safe. Synthetic materials can also be used to stimulate bone formation. We can even use factors from your own blood (called PRP) or use genetically engineered liquids, bone morphogenic protein (BMP) to accelerate and promote bone formation in graft areas.
Sinus lift procedure:
The maxillary sinuses are behind your cheeks and on top of the upper back teeth. Sinuses are air filled cavities above the the upper 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 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. We can enter the sinus from where the upper teeth used to be. The sinus membrane is then lifted upward and a pocket created. Then 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 several 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 at the same time, thus saving time using only one 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.
In severe cases, the ridge has been reabsorbed 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 gets too thin to place dental implants. In this procedure, the bony ridge of the jaw is literally expanded by placing the bone graft to the side of the thin ridge or on top. The bone graft material then will mature for a few months and fuse to the ridge before we can place the implant.