Bone Grafting

Major & Minor Bone Grafting

Over a period of time, the jawbone associated with missing teeth atrophies or is resorbed. This often leaves a condition in which there is poor quality and quantity of bone suitable for placement of dental implants. In these situations patients are not good candidates for placement of dental implants because the bone foundation is not adequate to support the implants.

Removal of tumors in the jaws or traumatic accidents can leave bone defects in the facial structure compromising function and cosmetics. Today, we have the ability to rebuild bone foundations where needed with bone grafting surgeries. This not only gives us the opportunity to place implants of proper length and width, it also gives us a chance to improve function and aesthetic appearance.

Minor Bone Grafting

Bone grafting can repair implant sites with inadequate bone structure due to previous extractions, gum disease, injuries or atrophy. The bone is either obtained from a tissue bank (allograft), or your own bone (autograft) is taken from the jaw, hip or tibia (below the knee). Sinus bone grafts are also performed to replace bone height in the posterior upper jaw. In addition to the bone materials, special membranes made of collagen may be utilized to protect the bone graft and encourage bone regeneration. These membranes resorb (dissolve) under the gum tissue after bone healing is complete. This technique is called guided bone regeneration or guided tissue regeneration.

Major Bone Grafting

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 (autograft). This bone is 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 routinely performed in an operating room and require a hospital stay.

Tissue Bank Bone

Bone grafts are used to fill bony defects, provide structural support, and build up deficient areas of the jaw when bone loss occurs. It is often necessary to rebuild the bone by using a bone graft prior to placing dental implants or dentures. There are different types of bone grafting materials available to treat various conditions. To avoid a harvest site surgery, Dr. Boerman may advise the use of an allograft (tissue harvested from a donor of the same species). Allograft bone has osseoconductive characteristics….in other words, it induces new bone formation in conjunction with your natural bone. Allografts act as a support or bridge for normal bone growth. Over time your own living cells will grow into the allograft replacing it with your own healthy new bone. The use of allografts is safe and effective. Allograft bone is screened and tested before being considered for donation and the bone undergoes a strict sterilization process. According to the American Association of Tissue Banks, over two million allografts have been transplanted in the last five years with no documented incident of disease transmission.

• www.tutogen.com

Ridge Preservation

In some cases when teeth are removed the defect (socket) may not predictably heal with normal contour, or the bone ridge that holds the teeth may collapse over time. If the bone foundation is compromised you may not be able to wear prosthetic tooth replacements or have implants placed for replacement of teeth. The placement of allograft bone into the sockets at the time of tooth extraction significantly improves healing and preserves bone shape to allow for predictable implant placement several months later. Dr. Boerman may advise that you have a ridge preservation procedure done at the time of your extractions to avoid the need for additional grafting surgery prior to implant placement.

Sinus Lift Procedure

The maxillary sinuses are behind your cheeks and above the upper teeth. Sinuses are air cavities. Some of the roots of the natural upper teeth may 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.

There is a solution and it’s called a sinus graft or sinus lift graft. The dental implant surgeon enters the sinus from where the upper teeth used to be. The sinus membrane is then lifted upward and donor bone is inserted into the floor of the sinus. Keep in mind that the floor of the sinus is the roof of the upper jaw. After several months of healing, the bone becomes part of the patient’s jaw and dental implants can be inserted and stabilized in this new sinus bone.

The sinus graft makes it possible for many patients to have dental implants, when years ago the only option was to wear loose dentures.

If enough bone between the upper jaw ridge and the bottom of the sinus is available to stabilize the implant well, 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 several months, depending upon the type of graft material used. Once the graft has matured, the implants can be placed.

Ridge Expansion

After removal of teeth the bone foundations (ridges) atrophy or shrink. In severe cases, the ridge has been reabsorbed and a bone graft is necessary to increase ridge height and/or width. Two common techniques used to restore the lost bone in preparation for implants are onlay grafting and ridge expansion. Onlay grafts require the use of cadaver bone or the patient’s own bone (harvested from the jaw or hip). Small screws are used to hold the grafted bone in place until the healing is complete. The screws are removed at the time of implant placement. With the ridge expansion procedure, the bony ridge of the jaw is split with an electric saw and literally expanded by mechanical means. After placement of the graft most patients will need 4-6 months of healing prior to placement of implants.

Nerve Repositioning

The inferior alveolar nerve, which gives feeling to the lower lip and chin, may need to be moved in order to make room for placement of dental implants in the lower jaw. This procedure is limited to the lower jaw and indicated when teeth are missing in the area of the two back molars and/or and second premolar, with the above-mentioned secondary condition. Any procedure with nerve tissue may cause some postoperative numbness of the lower lip and jaw area, which dissipates only very slowly, if ever. Usually other options (bone graft reconstruction) are considered first.

Typically, an outer section of the cheek side of the lower jawbone is removed in order to expose the nerve canal. The nerve and blood vessel bundle are gently moved out to the side. With the nerve out of the way the implants are placed. Then the bundle is released and placed back over the implants. The surgical access is filled with bone graft material of the surgeon’s choice before suturing.

Pre-Prosthetic Surgery

The preparation of your mouth before the placement of a prosthesis (denture) is referred to as pre-prosthetic surgery.

Some patients require minor oral surgical procedures before receiving a partial or complete denture, in order to ensure the maximum level of comfort. A denture sits on the bone ridge, so it is very important that the bone is the proper shape and size. If a tooth needs to be extracted, the underlying bone might be left sharp and uneven. For the best fit of a denture, the bone might need to be smoothed out or reshaped. Occasionally, excess bone would need to be removed prior to denture insertion.

One or more of the following procedures might need to be performed in order to prepare your mouth for a denture:

• Bone smoothing and reshaping
• Removal of excess bone
• Bone ridge reduction
• Removal of excess gum tissue
• Removal of impacted teeth

We will review your particular needs with you during your appointment.