Major & Minor Bone Grafting
Once a tooth is removed, over a period of time, the tooth socket ie. jawbone associated with the missing tooth/teeth atrophies or shrinks. This results in an insufficient quantity of bone suitable for placement of dental implants. In these situations, most patients are not candidates for placement of dental implants without bone grafting. Therefore if you are planning for an implant restoration, please let Dr. Yanagihara know at your initial consultation. Often a less invasive and less costly bone graft can be placed at the time of extraction to retard the bone shrinkage
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 aesthetic appearance by placing the implant(s) in the best possible position.
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 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. These procedures are routinely performed in an operating room and require a hospital stay.
Bone Grafting Overview
For a brief narrated overview of the bone grafting process, please click the image on the right. It will launch our flash educational MiniModule in a separate window that may answer some of your questions about bone grafting.
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Sinus Lift Procedure
The maxillary sinuses are membrane lined cavities located above your upper posterior teeth. Sinuses are like empty rooms that lighten the skull and warm the air we breathe. 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 to be encased completely in 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 bone graft. Dr. Yanagihara 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 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 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.
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 conventional implants. In this procedure, the bony ridge of the jaw is literally expanded by mechanical means. Bone graft material can be placed and matured for a few months before placing the implant.
The inferior alveolar nerve, which gives feeling to the lower lip and chin, is located in a canal in the posterior lower jaw beneath the premolars and molars. Placing an implant which violates this canal can result in permanent numbness to the lower lip, gums, teeth, and chin areas. Since this procedure is considered a very aggressive approach (there is almost always some permanent postoperative numbness to the lower lip, chin and jaw area, usually other, less aggressive options are considered first. Dr. Yanagihara would not encourage this procedure for anyone.
These procedures may be performed separately or together, depending upon the individual’s condition. As stated earlier, there are several areas of the body that are suitable for attaining bone for grafts. In the maxillofacial region, bone grafts can be taken from inside the mouth, in the area of the chin or third molar region, or in the upper jaw behind the last tooth. In more extensive situations, a greater quantity of bone can be attained from the hip or the outer aspect of the tibia at the knee.
In many cases, we can use 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 even use factors from your own blood to accelerate and promote bone formation in graft areas. Today we also utilize Bone Morphogenentic Protein (BMP). BMP is a protein found in your bone which causes stem cells to become bone forming cells thus growing bone where it is placed. BMP has been utilized by our Orthopedic colleagues for spine surgery for years with excellent success.