• Bone loss can occur in the upper and lower jaws for several reasons. Localized bone loss often occurs around diseased teeth due to periodontal (gum) disease, fractured teeth and dental infections. In addition over a period of time, the jawbone associated with missing teeth atrophies (bone resorption). This often leaves a condition in which there is poor quality and quantity of bone, unsuitable for placement of dental implants. In the past, patients with significant bone loss were not candidates for placement of dental implants.

    Today, we have the ability to grow bone where 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 esthetic appearance.

    Bone grafts can repair (augment) implant sites which have inadequate bone structure due to previous extractions, gum disease, infections or injuries. Commonly used bone graft materials include autogenous bone (your own bone), bank bone (cadaver bone), bovine bone and synthetic bone. The selection of graft material and surgical technique are based on the location and severity of the bone loss. In most cases, specially prepared cadaver bone and/or autogenous bone are utilized. Autogenous bone is usually taken from other areas of the jaw. Augmentation bone grafts can be accomplished virtually anywhere on the upper and lower jaws.

    The great majority of bone grafts required for implant placement are minor procedures which can easily be accomplished in the office under local anesthesia or intravenous sedation. Major bone grafts are utilized to repair extremely large defects of the jaws. These defects may arise as a result of traumatic injuries, tumor surgery, or congenital defects. Large defects are always repaired using the patient's own bone. Since a large amount of bone is needed to repair these extensive defects, the bone must be harvested from areas where there is an abundance of available bone .This bone can be harvested from a number of 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 performed in an operating room and require a hospital stay.
    Socket Preservation Grafting

    A socket preservation graft helps to preserve the bone at an extraction site for future implant placement. The area of the jaw bone that holds a tooth in place is called a tooth socket. After a tooth has been extracted, the bone that supported this tooth rapidly begins to melt away (bone resorption). In order to minimize bone resorption an immediate socket preservation bone graft can be placed. The goal is to provide enough bone for implant placement four months later. In many cases, this simple graft is all that is required to provide sufficient bone for implant placement. In some cases, either due to severe inflammation at the extraction site, a low maxillary sinus, extensive preexisting bone loss and /or diseased tissue at the extraction site, it is not possible to provide sufficient bone volume for implant placement with this procedure alone. In these circumstances additional bone grafting is required either at the time of implant placement, or as a staged procedure.
    The tooth is extracted with great care leaving as much socket bone intact as possible. After the tooth has been extracted, the socket is gently but thoroughly cleaned and debrided. A specially prepared cadaver bone graft is inserted into the socket and retained in place with a with a small collagen plug which is sutured into place over the socket. The collagen plug falls out by itself a week or two later. The site is reevaluated for implant placement four months after grafting. If sufficient bone is present the implant can be placed at that time.

    Sinus lift procedure

    The maxillary sinuses are located above the roots of the upper posterior teeth and below the eye socket. The maxillary sinuses are found behind the cheeks on either side if the nose. Sinuses are like empty rooms that are filled with air. The floor of the maxillary sinus is located just above the roots of the upper molars and second premolar. Frequently, these teeth extend up into the maxillary sinuses. When these upper teeth are removed, there is often just a thin layer of bone separating the maxillary sinus and the mouth. Dental implants need bone to hold them in place. A thin sinus floor will not provide enough bone to support a dental implant.

    The solution to this problem is called a sinus graft or sinus lift graft. Our doctor creates a small window in the thin bone on the lateral sinus wall where the maxillary posterior teeth had previously been extracted. The sinus membrane is then lifted upward and a bone graft is inserted into the floor of the sinus. The bone graft is usually a combination of specially prepared cadaver bone and bone harvested from the patient's lower jaw. Keep in mind that the floor of the sinus is the roof of the upper jaw. After six months of healing, the bone becomes solid enough to support an implant.

    The sinus graft makes it possible for many patients to have dental implants when years ago there was no other option other than wearing loose dentures.

    In many cases the bone beneath the sinus floor is slightly deficient but there is sufficient bone height to provide initial implant stabilization. In these situations sinus augmentation and implant placement can be performed simultaneously. This remarkably simple bone grafting technique is called a simultaneous internal sinus lift. It is 'internal' because the sinus floor graft site is approached from within the implant preparation site. This technique is a simple, elegant surgical solution which adds only a few minutes to the implant procedure. If the bone height is inadequate for initial implant stabilization, the sinus augmentation must be performed from the lateral approach as a staged procedure six months prior to implant placement.

    Ridge Expansion

    When severe bone loss has resulted in a ridge that is too narrow to support a dental implant, there are several bone grafting options available:

    • - Particulate Cadaver Bone Graft
    • - Ridge Split
    • - Onlay Cortical Bone Graft

    Particulate Cadaver Bone Graft

    A particulate cadaver bone graft is often utilized in cases where there is sufficient bone to provide initial implant support, but there is inadequate bone volume to fully cover the implant. This graft is usually placed simultaneously with implant insertion. A collagen membrane may be utilized to contain the graft and prevent soft tissue (gum tissue) from interfering with new bone formation. The membrane is broken down and eliminated by the body so removal at a future date is not required. This technique is often referred to as guided tissue regeneration,or guided bone regeneration.

    Ridge Split

    A ridge split is performed in cases where the ridge is too narrow to place an implant but wide enough to split. There must be sufficient bone height to support an implant to accomplish this procedure. The crest of the ridge is split along its length between the outer cortex and inner cortex. The ridge is carefully expanded as the implant is inserted. This creates a void in the center of the split ridge which is filled with a specially prepared cadaver bone graft. The implant is buried beneath the gum tissue and allowed to heal for six months. When this procedure is accomplished in the mandible, the procedure must be staged due to the dense non-elastic nature of the mandibular bone. The bone cuts (osteotomies) are accomplished three weeks prior to implant placement. This three week healing period assures excellent blood supply to the expanded bone by allowing the gum tissue to reattach to the bone in the area of the osteotomies before expansion takes place.

    Onlay Cortical Bone Graft

    An onlay cortical bone graft is performed in cases of severe bone loss. A small block of bone is harvested from the chin or the mandibular ramus (just posterior to the lower wisdom tooth area). These donor sites are surgically approached from within the mouth. The block of bone is screwed into the recipient site with specially designed tiny surgical bone screws. The area is allowed to heal for 4 to 6 months, at which time the screws are removed and the implant is placed.
    These surgeries are performed with complete comfort in our office under local anesthesia, nitrous oxide gas, IV sedation or general anesthesia.


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