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, and 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 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.
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.
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.
The Importance of Teeth for Jaw Bone Health
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. 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 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.
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
Reasons for Jaw Bone Loss & Deterioration
The following are the most common causes for jaw bone deterioration and loss that may require a bone grafting procedure:
When an adult tooth is removed and not replaced jaw bone deterioration may occur. 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 in the mouth, no longer receives the necessary stimulation and begins to break down, or resorb. The body no longer uses or “needs” the jaw bone, 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 18 months following the extraction and will continue gradually throughout your life.
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.
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.
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 jaw bone 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 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 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.
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.
Some conditions or syndromes are characterized by missing portions of the teeth, facial bones, jaw, or skull. Drs. Stopperich or Koutras may be able to perform a bone graft procedure to restore bone function and growth where it may be absent.
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. Drs. Stopperich or Koutras can perform a procedure called a “sinus lift” that can treat enlarged sinuses.