Bone grafting is often closely associated with dental restorations such as bridge work and dental implants.
In the majority of cases, the success of a restoration procedure can hinge on the height, depth, and width of the jawbone at the implant site. When the jawbone has receded or sustained significant damage, the implant(s) cannot be supported on this unstable foundation and bone grafting is usually recommended for the ensuing restoration.
There are several major factors that affect jaw bone volume:
Periodontal Disease – Periodontal disease can affect and permanently damage the jaw bone that supports the teeth. Affected areas progressively worsen until the teeth become unstable.
Tooth Extraction – Studies have shown that patients who have experienced a tooth extraction subsequently lose 40-60% of the bone surrounding the extraction site during the following three years. Loss of bone results in what is called a “bone defect”.
Injuries and Infections – Dental injuries and other physical injuries resulting from a blow to the jaw can cause the bone to recede. Infections can also cause the jaw bone to recede in a similar way.
Reasons for bone grafts
Bone grafting is a highly successful procedure in most cases. It is also a preferable alternative to having missing teeth, diseased teeth, or tooth deformities. Bone grafting can increase the height or width of the jawbone and fill in voids and defects in the bone.
There are essentially two basic ways in which bone grafting can positively impact the health and stability of the teeth:
Jaw Stabilization – Bone grafting stabilizes and helps restore the jaw foundation for restorative or implant surgery. Deformities can also be corrected and the restructuring of the bone can provide added support.
Preservation – Bone grafting can be used to limit or prevent bone recession following a tooth extraction, periodontal disease, or other invasive processes.
What Does Bone Grafting Involve?
Ridge Preservation – In this preventive procedure, bone mineral particles are placed into the defect that is present at the time a tooth is extracted. This bone mineral helps to prevent atrophy and is eventually replaced by your own, healthy, living bone. This provides a sound foundation for implant placement.
Block grafts – When atrophy has already occurred and the amount of remaining bone is not sufficient for the placement of dental implants, block bone grafts may be recommended. Block grafting involves removing small, rectangular pieces of bone from one area of the jaw and transplanting them to the area where implant placement is planned. The technique of block grafting is particularly useful for reconstructing areas where the bone is too thin to accommodate implants, or where bone height has been lost. The transplanted bone is secured to the new site with tiny titanium screws until it heals into the new location and becomes part of the existing bone. Dental implants can then be placed to complete the reconstruction.
Sinus lift – The bones of the upper jaw that are found above the back teeth (premolars and molars) contain a natural cavity that is filled with air. These hollow spaces are called the sinuses, and they are lined by a special membrane. As we get older, our sinuses get larger, often encroaching upon the back teeth, and especially into areas where upper back teeth have been lost. When this occurs, there may not be a sufficient amount of bone available for the placement of dental implants. In these cases, Dr. Karras may recommend a procedure known as a sinus lift. In this procedure, the sinus is entered below the lining membrane. The membrane is gently raised to create a space above the missing teeth, and bone, bone mineral, or a mixture of the two is placed to fill the space. This bone is incorporated into the area, allowing the successful placement of dental implants.
There are several types of bone grafts. Your dentist will determine the best type for your particular condition.
Autogenous Bone Graft – Harvested from the patient’s own body (usually from the posterior part of the lower jaw or the chin). This method is usually preferred because it produces the most predictable results.
BMP – BMP, or Bone Morphogenic Protein is a naturally ocurring protein found in our bones. BMP will actually cause the body to grow bone and can be used successfully to reconstruct larger defects where there is very little of the patient’s own bone remaining.
Allograft Bone Graft – This bone is derived from organ donors that have been carefully screened. The donor bone is processed until only the mineral content remains. When it is used as a graft, it is eventually replaced with your body’s own natural bone.
Xenograft – This is bone mineral derived from a bovine source.
The bone grafting procedure can often take several months to complete. Grafted bone will fuse with the existing bone and the migration of cells will cause firm adhesion and cell growth. Supplementing the jaw with bone will result in greater bone mass to help support and anchor the implant(s).