About Bone Grafting
What is Bone Grafting?
Over a period of time, the jaw bone associated with missing teeth atrophies and is reabsorbed. This often leaves a condition in which there is poor quality and quantity of bone suitable for the placement of dental implants. In these situations, most patients are not candidates for the placement of dental implants.
With bone grafting we now have the opportunity to not only replace bone where it is missing, but we also have the ability to promote new bone growth in that location. 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.
Types of Bone Grafts
Autogenous Bone Grafts
Autogenous bone grafts, also known as autografts, are made from your own bone, taken from somewhere else in the body. The bone is typically harvested from the chin, back of the jaw, lower leg bone, hip, or the skull. Autogenous bone grafts are advantageous in that the graft material is your own living bone, meaning it contains living cellular elements that enhances bone growth, also eliminating the risk of your body rejecting the graft material since it comes from you.
However, one downside to the autograft is that it requires a second procedure to harvest bone from elsewhere in the body. Depending on your condition, a second procedure may not be recommended.
Allogenic bone, or allograft, is bone harvested from a cadaver, then processed using a freeze-dry method to extract the water via a vacuum. Unlike autogenous bone, allogenic bone cannot produce new bone on it’s own. Rather, it serves as a framework, or scaffold, over which your bone cells from the surrounding bony walls can grow to fill or regenerate the defect or void.
Xenogenic bone is derived from non-living bone of another species, usually a cow. The bone is processed at very high temperatures to avoid the potential for immune rejection and contamination. Like allogenic grafts, xenogenic grafts serve as a framework for bone from the surrounding area to grow and fill the void.
Both allogenic and xenogenic bone grafting have an advantage of not requiring a second procedure to harvest your own bone, as with autografts. However, because these options lack autograft’s bone-forming properties, bone regeneration may take longer than with autografts. In large defects, they may have a less predictable outcome.
Bone Graft Substitutes
As a substitute to using real bone many synthetic materials are available as safe and proven alternatives, including:
Demineralized Bone Matrix (DBM)/Demineralized Freeze-Dried Bone Allograft (DFDBA)
This product is processed allograft bone, containing collagen, proteins, and growth factors that are extracted from the allograft bone. It is available in the form of powder, putty, chips, or as a gel that can be injected through a syringe.
Graft composites consist of other bone graft materials and growth factors to achieve the benefits of a variety of substances. Some combinations may include: collagen/ceramic composite, which closely resembles the composition of natural bone, DBM combined with bone marrow cells, which aid in the growth of new bone, or a collagen/ceramic/autograft composite. These composite materials may not be as predictible in healing for some individuals.
Bone Morphogenetic Proteins
Bone morphogenetic proteins (BMPs) are proteins naturally produced in the body that promote and regulate bone formation and healing. When combined with a resorbable support material like collagen, BMP call be used to grow new bone and is typically used for sinus lift grafting.
Stem cells are special cells that are able to develop into a wide range of cell types from muscle cells to brain cells. With age, the amount of stem cells we have rapidly decline. We are able to use a type of adult stem cell, called a mesenchymal stem cell (MSC), to form new bone. MSCs have a unique property in that they are considered “immunologically privileged”, that is they do not elicit an immune response from the body thus they cannot be rejected. We obtain them from a commercial tissue bank and mix them with allogenic bone (which serves as a scaffold) and use this combination for large sinus lift grafts, one of the two FDA approved uses for MSCs (the other is spinal fusion).
Each bone grafting option has its own risks and benefits. Drs. Yamada and Zeidan will determine which type of bone graft material is best suited to your particular needs during your consultation.