What is Bone Graft?
Do you think of bone as a hard, rigid material that never changes? In fact bone remodels itself all the time: Your body is constantly depositing new bone cells and removing old ones. In the case of the bone that supports your teeth, this process can be helpful or harmful. For example, the jawbone's adaptability allows an orthodontist to move teeth into a better position with braces. But in the case of losing a tooth as an adult, the bone changes that result can have serious consequences.
When teeth are lost, the bone that used to surround them begins to melt away or “resorb.” Tooth-supporting bone can also be lost when you have periodontal (gum) disease. If you lose enough teeth and bone, your facial features will sag, giving you a more aged appearance; it can also complicate treatment to replace your missing teeth. Fortunately, with modern bone grafting-techniques, the bone that has been lost can be built up again. This can benefit both your health and appearance by strengthening your jawbone, allowing more effective tooth replacement, and increasing support to your facial features.
Bone grafting is a minor surgical procedure that is normally done in a dental office. An incision is made in your gum to gain access to the bone beneath it, and then grafting material is added. Most often, the grafting material is processed bone minerals around which your body will actually deposit new bone cells.
The grafting material itself can come from your own body, but very often it is bone from an animal or human donor that has been treated by a laboratory to make it sterile and safe. It can even be a synthetic substance. Grafting material comes in a variety of forms: powder, granules, putty or a gel that can be injected through a syringe. The graft, which is generally covered by a collagen membrane for optimum bone repair, will act as a scaffold onto which your body will build new bone.
Bone Grafts Around Teeth or Implants
Localized bone loss often occurs around diseased teeth due to periodontal (gum) disease, fractured teeth, traumatic injuries and dental infections. When the bone loss occurs around teeth, the teeth can become loose and at risk of being lost. When the bone loss occurs around implants, the thread part of the implant gets exposed and the condition gets worse. In order to save them, the bone around them can be regenerated through grafting and the teeth or implants become stabilized. The gum will be opened up to expose the bone area. The area gets cleaned up, bone material placed and covered with membrane. The gum will be re-positioned and sutured together.
Bone Grafts After Extraction
This is referred to as a socket preservation graft, and it is placed directly into the socket immediately after tooth removal.
The area of the jaw bone that holds a tooth in place is called a tooth socket. Preservation of bone volume and architecture (shape) is crucial for implant stability and esthetics. After a tooth has been extracted, the supporting bone (socket) begins to rapidly melt away (bone resorption). Post-extraction bone resorption tends to be particularly severe in sockets with thin walls of bone. A socket preservation graft placed immediately after tooth extraction helps to preserve bone volume and architecture by minimizing post-extraction bone resorption. This procedure diminishes the likelihood that a more complicated bone graft will be necessary prior to implant placement. In many cases, this simple graft is all that is required to provide sufficient bone for implant placement.
The tooth is extracted with great care leaving as much socket bone intact as possible. After the tooth has been extracted, the socket is gently but thoroughly cleaned and debrided. A specially prepared bone graft material is inserted into the socket and retained in place with sutures over the socket. The site is reevaluated for implant placement four months after grafting; if sufficient bone is present the patient is ready to be scheduled for implant surgery.
When severe bone loss has resulted in a very thin or narrow bone ridge, bone graft is needed expand the ridge. Incision is made and the gum flap is elevated to expose the bone area. Bone graft material is added and a non-resorbable membrane is usually covered up to keep the shape and volume. Gum flap is re-positioned and sutured together. During the 6-7 months of healing time, the ridge gets thicker and wide enough for implants. If non-resorbable membrane is used, it needs to be removed later time - usually at the time of implant placement.
The maxillary sinuses are empty space located behind the cheek bones, above the roots of the upper back teeth and below the eye socket. The floor of the maxillary sinus is located just above the roots of the upper molars and second premolar. Frequently, the roots of these teeth extend up into the maxillary sinuses. When these upper teeth are removed, there is often just a thin layer of bone separating the maxillary sinus and the mouth. A thin sinus floor will not provide enough bone to support a dental implant.
The solution to this problem is called a maxillary sinus graft or maxillary sinus lift graft. A small window is created in the thin bone on the lateral sinus wall where the maxillary posterior teeth had previously been extracted. The delicate sinus membrane is carefully exposed then lifted upward and a bone graft is inserted beneath the membrane into the floor of the sinus. After six months of healing, when the bone becomes solid enough to support an implant, the implants are placed.
The sinus graft makes it possible for many patients to have dental implants when years ago their only option was to wear dentures, partial dentures or bridges.
In many cases the bone beneath the sinus floor is slightly deficient but there is sufficient bone height to provide initial implant stabilization. In these situations sinus grafting and implant placement are performed simultaneously. This remarkably simple bone graft procedure is called a vertical sinus lift. The sinus floor graft site is approached from within the implant preparation site. This is an elegant surgical technique reduces the total healing period by approximately six months.