Bone Grafting

When one or more teeth are missing it can lead to bone loss at the site of the gap. This loss of jaw bone can develop into additional problems, both with your appearance and your overall health.

In the same way that muscles are maintained through exercise, bone tissue is maintained by use. Natural teeth are embedded in the jaw bone and stimulate the jaw bone through activities such as chewing and biting. When teeth are missing, the alveolar bone, or the portion of the jaw bone that anchors the teeth into the mouth, no longer receives the necessary stimulation it needs and begins to break down, or resorb. The body no longer uses or “needs” the jaw bone, so it deteriorates.

Reasons for Jaw Bone Loss and Deterioration

The following are the most common causes for jaw bone deterioration and loss that may require a bone grafting procedure:

• Tooth Extractions
• Periodontal/Gum Disease
• Dentures/Bridgework
• Facial Trauma
• Osteomyelitis
• Tumors
• Developmental Deformities
• Sinus Deficiencies

Potential Consequences of Tooth and Jaw Bone Loss

• Problems with remaining teeth, including misalignment, drifting, loosening, and loss
• Collapsed facial profile
• Limited lip support
• Skin wrinkling around the mouth
• Distortion of other facial features
• Jaw (TMJ or temporomandibular joint) pain, facial pain, and headaches
• Difficulty speaking and communicating
• Inadequate nutrition as a result of the inability to chew properly and painlessly
• Sinus expansion

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, jaw, lower leg bone, hip, or the skull. Autogenous bone grafts are advantageous in that the graft material is your own live 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

Allogenic bone, or allograft, is dead 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 its own. Rather, it serves as a framework, or scaffold, over which bone from the surrounding bony walls can grow to fill the defect or void. Examples are Demineralized Bone Matrix (DBM)/Demineralized Freeze-Dried Bone Allograft (DFDBA)

Xenogenic Bone

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, and have a less predictable outcome.

Bone Morphogenetic Proteins

Bone morphogenetic proteins (BMPs) are proteins naturally produced in the body that promote and regulate bone formation and healing.

Socket preservation

Preserving Your Jaw Bone after Extraction

Removal of teeth is sometimes necessary because of pain, infection, bone loss, or due to a fracture in the tooth. The bone that holds the tooth in place (the socket) is often damaged by disease and/or infection, resulting in a deformity of the jaw after the tooth is extracted. In addition, when teeth are extracted the surrounding bone and gums can shrink and recede very quickly, resulting in unsightly defects and a collapse of the lips and cheeks.

These jaw defects can create major problems in performing restorative dentistry whether your treatment involves dental implants, bridges, or dentures. Jaw deformities from tooth removal can be prevented and repaired by a procedure called socket preservation. Socket preservation can greatly improve your smile’s appearance and increase your chances for successful dental implants.

Several techniques can be used to preserve the bone and minimize bone loss after an extraction. In one common method, the tooth is removed and the socket is filled with bone or bone substitute. It is then covered with gum, artificial membrane, or tissue, which encourages your body’s natural ability to repair the socket. With this method, the socket heals, eliminating shrinkage and collapse of the surrounding gum and facial tissues. The newly formed bone in the socket also provides a foundation for an implant to replace the tooth. This procedure adds no pain or downtime to the tooth removal.

If socket preservation is not performed at the time of tooth removal a ridge augmentation will frequently need to be performed. Bone is much harder to “grow” than it is to maintain. Ridge augmentation is more time intensive, has more downtime, and costs more. This is why Dr. Khan frequently recommends performing socket preservation procedure with tooth extraction.

Ridge augmentation

What is a ridge augmentation?

A ridge augmentation is a common dental procedure often performed following a tooth extraction if a socket preservation was not performed at the time of tooth removal. This procedure helps recreate the natural contour of the gums and jaw that may have been lost due to bone loss.

The alveolar ridge of the jaw is the bone that surrounds the roots of teeth. When a tooth is removed an empty socket is left in the alveolar ridge bone. If a bone replacement graft is placed at the time of extraction the bone will be maintained. This is know as “socket preservation”. If this is not performed some bone loss will occur. Over the course of a year this can be up to 25% of volume at that site.
Rebuilding the original height and width of the alveolar ridge is not always medically necessary, but may be required for dental implant placement or for aesthetic purposes. Dental implants require bone to support their structure and a ridge augmentation can help rebuild this bone to accommodate the implant.

How is a ridge augmentation accomplished?

A ridge augmentation is accomplished by making a small incision in the gums. Next bone graft material is placed at the site where the tooth was extracted. The gum tissue is then placed over the site and secured with sutures. Dr. Khan may choose to use a space-maintaining product over the top of the graft to facilitate new bone growth. Once the socket has healed, the alveolar ridge can be prepared for dental implant placement.

A ridge augmentation procedure is typically performed in office using intravenous sedation.

Sinus lift

What is a sinus lift?

The maxillary sinuses are behind your cheeks and on top of the upper teeth. These sinuses are empty, air-filled spaces. 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. Dental implants need bone to hold them in place. When the sinus wall is very thin, it is impossible to place dental implants in this bone.

The key to a successful and long-lasting dental implant is the quality and quantity of jaw bone to which the implant will be attached. If bone loss has occurred due to injury or periodontal disease, a sinus augmentation can raise the sinus floor and allow for new bone formation. A sinus lift is one of the most common bone grafting procedures for patients with bone loss in the upper jaw. The procedure seeks to grow bone in the floor of the maxillary sinus above the bony ridge of the gum line that anchors the teeth in the upper jaw. This enables dental implants to be placed and secured in the new bone growth.

Am I a candidate for a sinus lift procedure?

A sinus lift may be necessary if you:

• are missing more than one tooth in the back of your jaw
• are missing a significant amount of bone in the back of your jaw
• are missing teeth due to a birth defect or condition
• are missing most of the maxillary teeth and require support for dental implants

How is a sinus lift accomplished?

Most commonly, a small incision is made on the premolar or molar region to expose the jaw bone. A small opening is cut into the bone, and the membrane lining the sinus is pushed upward. The underlying space is filled with bone grafting material, either from your own body or from other sources. Sometimes, synthetic materials that imitate bone formation are used. After the bone is implanted, the incision is sutured and the healing process begins. After several months of healing, the bone becomes part of the patient’s jaw and dental implants can be inserted and stabilized in the newly formed sinus bone.

If enough bone between the upper jaw ridge and the bottom of the sinus is available to sufficiently stabilize the implant, sinus augmentations and implant placement can sometimes be performed as a single procedure. If not enough bone is available, the sinus augmentation will have to be performed first, then the graft will have to mature for up to several months, depending upon the type of graft material used. Once the graft has matured, the implants can be placed.

The sinus graft makes it possible for many patients to have dental implants that previously had no other option besides wearing loose dentures.

Bone morphogenetic protein

Bone morphogenic protein is an isolated protein that induces specific cells in our body to form new cartilage and bone. During surgery, the BMP is soaked onto and binds with a collagen sponge. The sponge is then designed to resorb, or disappear, over time. As the sponge dissolves, the bone morphogenic protein stimulates the cells to produce new bone. The BMP also goes away once it has completed its task of jump starting the normal bone healing process.

Since there is no need to harvest bone from the patients’ hip for BMP, recipients were spared donor site pain. Complications from the graft harvest site are also eliminated with the use of bone morphogenic protein.