Bone and Soft Tissue Grafting
Following tooth loss the bone surrounding the root is no longer stimulated and begins to resorb. Although bone will fill the socket the result is an overall loss of jawbone in the site. This can negatively impact the appearance of the gum making tooth replacement less esthetic. Over time the use of dentures resting on the gum causes further atrophy (bone loss). Loss of supporting bone can age your facial appearance and make dentures more difficult to wear. It also contributes to loss of chewing function making eating less pleasurable. Patients begin to select softer foods that often have less nutritional value. Jaw atrophy can leave a condition in which there is poor quality and quantity of bone suitable for placement of dental implants. In these situations patients may not be good candidates for placement of dental implants without bone grafting.
Oral surgeons have unique training in jaw reconstruction and Dr. Misch has been a pioneer in the field of bone regeneration surgery for dental implants. Today we have the ability to grow bone where needed. This gives us the opportunity to place an adequate number of implants in proper positions to support the replacement teeth. It also allows us to restore esthetic appearance and create a beautiful smile. There are several materials and methods that can be used to rebuild missing bone. Dr. Misch will select the approach that offers the best outcome in your particular case.
Socket Bone Grafting
When a tooth is removed it may be possible to immediately place the dental implant. However, in some cases conditions are not favorable for this option. Infection, bone loss around the root, or lack of adequate remaining bone may prevent immediate implant insertion. In these instances a bone graft material is placed into the socket to help prevent bone loss and facilitate repair. Bone substitutes work very well as a scaffold for bone fill over time. In the front part of the mouth we provide temporary tooth replacement for use during healing. Typically in two to four months the dental implant can be inserted into the healed site.
Sinus Bone Grafting
The sinuses are hollow cavities located in the back of the upper jaw. In many patients the sinus floor is in close approximation to the tooth roots. When the back teeth are lost the bone around the roots resorbs leaving inadequate bone below the hollow sinus for implant placement. In some cases we can use shorter implants to anchor into the bone below the sinus. When there is inadequate bone we may need to add bone graft material along the sinus floor. The sinus is not penetrated but repositioned further superior. The sinus has a lining that is much like a balloon within the cavity. The balloon lining is elevated and a bone substitute is placed below it along the sinus floor. Performed by an experienced oral surgeon, sinus bone grafting is a proven safe and effective method to rebuild upper jaw bone. In some cases dental implants can be placed at the same time the bone graft is inserted. Otherwise the bone graft is allowed to heal and implants are placed four to six months later. Dr. Misch was a member of the 1996 Sinus Bone Graft Consensus Conference and has published and lectured extensively on this technique.
When teeth have been missing for some time the bony ridge of the jaw may be too resorbed to place implants. Injuries to the mouth causing tooth loss can also result in bone deficiencies. The ridge may be too narrow or there may not be adequate bone height to place implants. There are several methods that can be used to rebuild the missing bone. Guided Bone Regeneration can be used to repair small bone defects. A bone graft material is placed over the bone defect and is covered by a thin membrane that protects the graft during healing. In some cases Ridge Expansion can be used with special instruments to widen the bone. Dr. Misch may recommend the use of your own bone to rebuild the ridge. Block Bone Grafts may be obtained from different sites in the body depending on how much bone is needed. In most patients requiring this approach, we can obtain bone from within the mouth using the upper or lower jaw. Dr. Misch developed the Ramus Bone Graft technique that uses bone from the back of the lower jaw behind the molars. This has become one of the most commonly used surgical procedures in the world to augment the jaw. In extreme instances he may need to use bone from the hip to reconstruct larger amounts of missing bone. Fortunately new advancements in bone regeneration have largely replaced the common need for harvesting your own bone. However, Dr. Misch will always recommend the best technique for your case as well as any alternatives that may also be effective. The need for bone grafting will add treatment time to your case. A bone graft heals much like a broken bone so adequate time is needed to heal.
Types of Bone Grafts
Autogenous bone refers to a bone graft taken from one area of the patient’s own body and transplanted onto the deficient part of the jaw. As previously mentioned bone can often be obtained from local sites within the mouth using the upper or lower jaw. The bone can be harvested as a small block or particles can be collected. Large bone defects or advanced bone loss may require the use bone from the hip. This procedure is done in an operating room under a general anesthesia.
In most cases bone substitutes can be utilized to repair bone defects. One option is to use donated human bone mineral from a tissue bank. This type of bone graft is safe as it is processed and sterilized so there is no risk of disease transmission or infection. Another alternative is the use of animal products such as bovine (cow) or porcine (pig) bone. The use of animal bone mineral is also well documented as a safe and effective option. In some cases artificial bone made in the laboratory from calcium phosphate can be used. Your body looks at these bone substitutes as “old bone” that needs to be replaced with new tissue. New bone will also grow around graft particles and incorporate them into the jaw. Dr. Misch will always recommend the best material to grow bone in your case as well as any alternatives that may also be effective.
A relatively new approach uses tissue engineering techniques to stimulate bone formation. Platelet rich plasma can be obtained from the blood to stimulate healing after surgery. Platelets contain growth factors that attract cells involved in the repair of tissues following injury. A small amount of blood is drawn from a vein and processed to remove the platelets. Research has produced special proteins that are synthesized in the laboratory to replicate our body’s own growth factors that work to repair bone such as in fracture healing. Bone morphogenetic protein (BMP) is made by our bone cells to facilitate formation of new bone. BMP attracts your own stem cells to the area and instructs those cells to start forming bone. The surgeon places the synthetic BMP in the defective area to direct new bone growth. Dr. Misch has performed clinical research on BMP and is one of the leading authorities on its use in dentistry (viewable here and here). Another commercial product is platelet derived growth factor (PDGF). This growth factor attracts reparative cells and stimulates them to heal surgical wounds. In most cases these special proteins are mixed with bone substitutes to rebuild the missing bone. Continued research in this exciting area of regenerative medicine will undoubtedly further improve our ability to grow new bone in the future.
Soft Tissue Grafting
The most common reason adults lose teeth is from periodontal or gum disease. Periodontal disease causes the loss of supporting bone and gum (gingiva) around the teeth. In addition to bone grafting it is sometimes necessary to replace the missing gingiva or soft tissue. Gingival grafts can be obtained from the roof of the mouth or hard palate. A piece of soft tissue is removed and transplanted to the defective site. The surgical wound on the palate heals over a short time period. In some cases we can use donated grafts from a tissue bank. This dermal graft is obtained from processed human or animal tissue. The obvious benefit of this option is that the surgeon does not need to use the patient’s own palatal tissue as a donor site.