MAKING THE WORLD BETTER. ONE SMILE AT A TIME
major and minor Bone Augmentation procedures
Following extraction or loss of teeth, the jawbone is reabsorbed in height and width. This often results in a situation where the quality or quantity of bone is not suitable for implant placement. By the process of guided bone regeneration, we can “grow” bone where it is needed. 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.
Minor bone augmentation (grafting) procedures can repair implant sites where there is inadequate bone structure due to early tooth loss, disease, or injuries.
Bone is either obtained from a tissue bank (human or animal products), or your own bone can be harvested from your jaw or hip.
Where the maxillary sinuses are involved (mainly posterior jaw), bone augmentation procedures can be performed to increase the amount of bone between the jaw and the sinus floor. Special resorbable or non-resorbable membranes (barriers) can be utilized to protect the bone graft site and encourage bone regeneration.
Major bone grafts are typically performed to repair defects of the jaws. These defects may arise because of traumatic injuries, tumour surgery, or congenital defects. Large defects are repaired using the patient’s own bone. This bone is harvested from several different sites depending on the size of the defect. 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.
Reasons for Jawbone Loss and Deterioration
The following are the most common causes for jawbone deterioration and loss that may require a bone grafting procedure:
- Tooth Extractions:
When a permanent tooth is removed and not replaced by an implant, jawbone resorption will occur. Natural teeth are embedded in alveolar jawbone and physiologically stimulate the jawbone through activities like masticating and biting. The rate 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 continues throughout life.
- Periodontal Disease:
Periodontal diseases are ongoing infections of the gums and underlying bone that gradually destroys the supporting alveolar bone. Periodontal disease affects one or more of the periodontal tissues: alveolar bone, periodontal ligament, cementum, or gingiva. While there are many diseases which 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. If gingivitis progresses into periodontitis, the supporting gum tissue and bone that holds teeth in place deteriorates. The progressive loss of the alveolar bone can lead to loosening and subsequent loss of teeth.
Unanchored dentures are placed on top of the oral mucosa and therefore 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.
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.
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.
Osteomyelitis is a type of bacterial infection in the bone and bone marrow of the jaw. The infection leads to inflammation, which can cause a reduction of blood supply to the bone. Treatment for osteomyelitis generally requires antibiotics and removal of the affected bone. A bone graft procedure may then be required to restore bone function and growth lost during removal.
Benign facial tumours, though generally non-threateningly, may grow large and require removal of a portion of the jaw. Malignant mouth tumours almost always spread into the jaw, requiring removal of a section of the jaw. In both cases, reconstructive bone grafting is usually required to help restore function to the jaw. Grafting in patients with malignant tumours may be more challenging because treatment of the cancerous tumour generally requires removal of surrounding soft tissue as well.
- Developmental Deformities:
Some conditions or syndromes known as birth defects are characterized by missing portions of the teeth, facial bones, jaw or skull.
Types of Bone Grafts
- Autogenous Bone Grafts:
Autogenous bone grafts, also known as autografts, are made from the patients’ 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 vital bone, meaning it contains living cellular elements that enhance bone growth.
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 in your best interest.
- 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.
- Xenogenic Bone:
Xenogenic bone is derived from non-living bone of another species, usually bovine. The bone is processed at very high temperatures to avoid the potential for immune rejection and contamination. Like allogenic grafts, xenografts serve as a framework for bone from the surrounding area to grow and fill the void.
Both allogenic and xenogenic bone grafting are advantageous in that they do not require a second procedure to harvest the bone, as with autografts. However, because these options lack autograft’s bone-forming properties, bone regeneration may take longer than with autografts, with a less predictable outcome.
Bone Graft Substitutes
As a substitute to using real bone, many synthetic materials are available as a safe and proven alternative, 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.
*What is a Ridge Augmentation?
A ridge augmentation is a common dental procedure often performed following a tooth extraction to help recreate the horizontal and vertical dimensions of the alveolar bone that may have been lost because of a tooth extraction, or for another reason.
Rebuilding the original height and width of the alveolar ridge is not 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.
*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.
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.
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, but require support for dental implants.