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.
Today, we have the ability to grow bone where it is needed. This not only gives us the opportunity to place implants of proper length and width, but 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 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 growth. 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.
Sinus Lift Procedure
The maxillary sinuses are behind your cheek bones 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 is called a sinus lift procedure with bone grafting. Drs. Curry and Butler enter 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 patients 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 adequate bone exists to stabilize the implant(s), sinus augmentation and implant placement can sometimes be performed as a single procedure. If there is inadequate bone, the sinus augmentation will have to be performed first and after allowing adequate time for bone formation, the implants can then be placed.
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 lower jaw and tibia are common donor sites. Occasionally, the hip is used to obtain a larger quantity of bone if needed.
As stated earlier, there are several areas of the body that are suitable for obtaining bone grafts. In the maxillofacial region, bone grafts can be taken from inside the mouth, in the area of the chin, 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 below the knee. When we use the patients own bone for repairs, we generally get the best results.
In many cases, we can use allograft materials 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.
These surgeries are performed in our office surgical suites under IV sedation or general anesthesia. After discharge, bed rest is recommended for one day and limited physical activity for one week.
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 gets too thin to place conventional implants. Bone graft material can be placed and allowed to mature for a few months before placing the implant.
Nerve - Repositioning
The inferior alveolar nerve, which gives feeling to the lower lip and chin, may need to be moved in order to make room for placement of dental implants to the lower jaw. This procedure is limited to the lower jaw when posterior teeth are missing. Since this procedure is considered a very aggressive approach (there is almost always some postoperative numbness of the lower lip and chin area, which dissipates only very slowly, if ever) usually other less aggressive options are considered first.
Typically, we remove the outer section of the lower jawbone in order to expose the nerve and vessel canal. Then we isolate the nerve and vessel bundle in that area, and slightly pull it out to the side. At the same time, we will place the implants. The surgical access is refilled with bone graft material of the surgeons choice and the area is closed.