What is Bone Grafting
Over a period of time, the jawbone 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.
Missing teeth over a period of time can cause your jawbone to atrophy, or resorb. This often results in poor quality and quantity of bone suitable for the placement of dental implants as well as long term shifting of remaining teeth and changes to facial structure. Most patients, in these situations, are not candidates for dental implants.
Fortunately, today we have the ability to grow bone where it is needed. This not only gives us the opportunity to place implants of proper length and width, but it also gives us a chance to restore functionality and aesthetic appearance
Bone grafting can repair implant sites with inadequate bone structure due to previous extractions, gum disease, or injuries. The bone is either obtained from a tissue bank or your own bone is taken from the jaw, hip or tibia (below the knee). Sinus bone grafts are also performed to replace bone in the posterior upper jaw. In addition, special membranes may be utilized that dissolve under the gum to protect the bone graft, as well as encourage bone regeneration. This is called guided bone regeneration, or guided tissue regeneration.
Major bone grafts are typically performed to repair defects of the jaws. These defects may arise as a result of traumatic injuries, tumor surgery, or congenital defects. Large defects are repaired using the patient’s own bone. This bone is harvested from a number of different areas depending on the size needed. The skull (cranium), hip (iliac crest), and lateral knee (tibia), are common donor sites. These procedures are routinely performed in an operating room and require a hospital stay.
We will decide which type of bone graft to use before your surgery.
Our surgeon will make an incision in the skin above where the graft is needed. They’ll then shape the donated bone to fit the area. The graft will be held in place using any of the following: pins, plates, screws, wires, or cables.
Once the graft is securely in place, we will close the incision with stitches and bandage the wound. A cast or splint may be used to support the bone while it heals. Many times, no casting or splint is necessary.
Reasons for Jawbone Loss and Deterioration
When one or more teeth are missing it can lead to bone loss at the site of the gap. This loss of jawbone can develop into additional problems, both with your appearance and your overall health. You may experience pain, problems with your remaining teeth, altered facial appearance, and eventually even the inability to speak and/or eat normally.
In the same way that muscles are maintained through exercise, bone tissue is maintained by use. Natural teeth are embedded in the jawbone and stimulate the jawbone through activities such as chewing and biting. When teeth are missing, the alveolar bone, or the portion of the jawbone 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 jawbone, so it deteriorates.
Causes of Jawbone Loss
Tooth Extractions | When an adult tooth is removed and not replaced jawbone deterioration may occur. Natural teeth are embedded in the jawbone and stimulate the jawbone through activities such as chewing and biting. When teeth are missing, the alveolar bone, or the portion of the jawbone that anchors the teeth in the mouth, no longer receives the necessary stimulation and begins to break down, or resorb. The body no longer uses or “needs” the jawbone, so it deteriorates and goes away.
The rate that the bone deteriorates, as well as the amount of bone loss that occurs, varies greatly among individuals. However, most loss occurs within the first eighteen months following the extraction and will continue gradually throughout your life.
Periodontal Disease | Periodontal diseases are ongoing infections of the gums that gradually destroy the support of your natural teeth. Periodontal disease affects one or more of the periodontal tissues: alveolar bone, periodontal ligament, cementum, or gingiva. While there are many diseases that affect the tooth-supporting structures, plaque-induced inflammatory lesions make up the majority of periodontal issues and are divided into two categories: gingivitis and periodontitis. While gingivitis, the less serious of the diseases, may never progress into periodontitis, it always precedes periodontitis.
Dental plaque is the primary cause of gingivitis in genetically-susceptible individuals. Plaque is a sticky colorless film, composed primarily of food particles and various types of bacteria, that adheres to your teeth at and below the gum line. Plaque constantly forms on your teeth, even minutes after cleaning. Bacteria found in plaque produces toxins, or poisons, that irritate the gums. Gums may become inflamed, red, swollen, and bleed easily. If this irritation is prolonged, the gums will separate from the teeth causing pockets (spaces) to form. If daily brushing and flossing is neglected, plaque can harden into a rough, porous substance known as calculus (or tartar). This can occur both above and below the gum line.
Periodontitis is affected by bacteria that adheres to the tooth’s surface, along with an overly aggressive immune response to these bacteria. If gingivitis progresses into periodontitis, the supporting gum tissue and bone that hold teeth in place deteriorates. The progressive loss of this bone, the alveolar, can lead to the loosening and subsequent loss of teeth.
Dentures/Bridgework | Unanchored dentures are placed on top of the gum line, but they do not provide any direct stimulation to the underlying alveolar bone. Over time the lack of stimulation causes the bone to resorb and deteriorate. Because this type of denture relies on the bone to hold them in place, people often experience loosening of their dentures and problems eating and speaking. Eventually, bone loss may become so severe that dentures cannot be held in place with strong adhesives, and a new set of dentures may be required. Proper denture care, repair, and refitting are essential to maintaining oral health.
Some dentures are supported by anchors, which do help adequately stimulate, and therefore preserve bone.
With bridgework, the teeth on either side of the appliance provide sufficient stimulation to the bone, but the portion of the bridge that spans the gap where the teeth are missing receives no direct stimulation. Bone loss can occur in this area. By completing a bone graft procedure, Dr. Skigen is now able to restore bone function and growth, thereby halting the effects of poor denture care.
Trauma | When a tooth is knocked out or broken to the extent that no biting surface is left below the gum line, bone stimulation stops, which results in jawbone loss. Some common forms of tooth and jaw trauma include teeth knocked out from injury or accident, jaw fractures, or teeth with a history of trauma that may die and lead to bone loss years after the initial trauma.
A bone grafting procedure would be necessary to reverse the effects of bone deterioration, restoring function and promoting new bone growth in traumatized areas.
Misalignment | Misalignment issues can create a situation in the mouth where some teeth no longer have an opposing tooth structure. The unopposed tooth can over-erupt, causing deterioration of the underlying bone.
Issues such as TMJ problems, normal wear-and-tear, and lack of treatment can also create abnormal physical forces that interfere with the teeth’s ability to grind and chew properly. Over time, bone deterioration can occur where the bone is losing stimulation.
Osteomyelitis | Osteomyelitis is a type of bacterial infection in the bone and bone marrow of the jaw. This infection leads to inflammation, which can cause a reduction of blood supply to the bone. Treatment for osteomyelitis generally requires antibiotics and the removal of the affected bone. A bone graft procedure may be required to restore bone function and growth lost during removal.
Tumors | Benign facial tumors, though generally non-threatening, may grow large and require the removal of a portion of the jaw. Malignant mouth tumors almost always spread into the jaw, requiring the removal of the affected section of the jaw. In both cases, reconstructive bone grafting is usually required to help restore normal function to the jaw. Grafting in patients with malignant tumors may be more challenging because treatment of the cancerous tumor generally requires removal of the surrounding soft tissues as well.
Developmental Deformities | Some conditions or syndromes are characterized by missing portions of the teeth, facial bones, jaw or skull. Dr. Skigen may be able to perform a bone graft procedure to restore bone function and growth where it may be absent.
Sinus Deficiencies | When molars are removed from the upper jaw, air pressure from the air cavity in the maxilla (maxillary sinus) causes resorption of the bone that formerly helped keep the teeth in place. As a result, the sinuses become enlarged, a condition called hyperpneumatized sinus.
This condition usually develops over several years and may result in insufficient bone from the placement of dental implants. Dr. Skigen can perform a procedure called a “sinus lift” that can treat enlarged sinuses.
Potential Consequences of Tooth and Jawbone 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
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, 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 it’s 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.
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 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.
Bone Morphogenetic Proteins
Bone morphogenetic proteins (BMPs) are proteins naturally produced in the body that promote and regulate bone formation and healing.
Synthetic materials also have the advantage of not requiring a second procedure to harvest bone, reducing risk and pain. Each bone grafting option has its own risks and benefits. Dr. Skigen will determine which type of bone graft material best suited to your particular needs.