Bone grafting of the top jaw (maxilla) or bottom jaw (mandible) can be necessary for many reasons. Removal of large areas of bone for pathology (cancer, cysts, tumors, etc), congenital defects (clefts, etc) and trauma require large amounts of bone grafting. More commonly, smaller grafting is needed for loss of teeth. Today, we have the ability to replace bone as needed, providing an opportunity to restore functionality and cosmetic appearance.
Minor Bone Grafting
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. Several forms of minor bone grafting are available to optimize dental implant placement.
Ideal dental implant placement requires sufficient height and width of the tooth bearing bone (alveolus) in the correct position with favorable ridge architecture. Following the removal of a tooth, the alveolar bone resorbs, losing as much as half of the width in the first year. Two-thirds of this loss occurs in the first 3 months following the extraction. Ridge preservation is bone grafting at the time of extraction, which has been shown to prevent the ridge from shrinking for several months. This is the most effective and efficient form of grafting available, and any tooth being removed should have ridge preservation considered for possible future implant placement. Often, a ridge preservation bone graft can prevent more invasive bone grafting surgery in the future.
Sinus Lift Procedure
The maxillary sinuses are behind your cheeks 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. When the height of bone is insufficient for a dental implant in this region a sinus lift procedure is required.
The oral surgeon 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, sinus augmentation will have to be performed first. The graft will have to mature for several months prior to the implants being placed.
When teeth are lost the supporting bone left behind is called a ridge. Over time the ridge will shrink and prevent the placement of dental implants. Bone grafts can be placed to increase the height and/or width of the ridge to allow tooth replacement using implants. Grafts most commonly are from external sources, but can come from various areas of the jaws, for example in the area of the chin, the wisdom tooth region of the lower jaw or in the upper jaw behind the last tooth.
Major Bone Grafting
Major bone grafting can repair larger defects due to pathology, congenital defects or injuries. 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), and are common donor sites. These procedures are routinely performed in an operating room and require a hospital stay.