Major and 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 the placement of dental implants. In these situations, most patients are not candidates for the placement of dental implants. Frequently Dr. Bowler will arrange CT scans and a special implant planning computer programme (SimPlant) to evaluate the quality and quantity of the available bone to determine whether bone grafting is required. Dr. Bowler will show you this on the practice computer prior to you making a final decision about bone grafting.
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.
Major Bone Grafting:
Bone grafting can repair implant sites with inadequate bone structure due to previous extractions, gum disease or injuries. The bone that is obtained is your own bone taken from the jaw or the hip. Sinus bone grafts can be performed to replace the bone in the posterior upper jaw. On occasions, special membranes may be utilised that dissolve under the gum but protect the bone graft and 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, tumour surgery, or congenital defects. Large defects are repaired using the patients own bone. The bone is harvested from a number of different sites depending on the size of the defect. The skull (cranium), hip (iliac crest), and ribs are common donor sites. These procedures are routinely performed in an operating theatre and require a hospital stay of usually 48 hours.
Sinus Lift Procedure:
The maxillary sinuses are large empty spaces behind your cheek bones and on top of the upper teeth. Some of the roots of the natural upper teeth extend up into the maxillary sinuses, when these 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, therefore when the sinus wall is very thin, it is impossible to place dental implants in this bone.
There is a solution and it is called a sinus graft or sinus lift graft. Your oral and maxillofacial surgeon enters the sinus from where the upper teeth used to be, the sinus membrane is then lifted upwards 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 patients jaw and dental implants can be inserted and stabilised in this new sinus bone.
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.
If enough bone is available, sinus augmentation 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 on the type of graft material used. Once the graft has matured, the implants can be placed.
In severe cases where the ridge has been resorbed a bone graft can be placed to increase ridge height and/or width. This is a technique used to restore the lost bone dimension when the jaw ridge gets too thin to place conventional implants. In this procedure, the bony ridge of the jaw is literally expanded by mechanical means. Bone graft material can be placed and matured for a few months before placing the implant.
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 to the lower jaw. This procedure applies only to the lower jaw and is indicated when teeth are missing in the area of the two back molars and/or 2nd premolar, with significant bony resorption which would not allow conventional implant placement.
Typically, we remove an outer section of the cheek side of the lower jawbone in order to expose the nerve and vessel canal. Then we isolate the nerve and vessel bundle in that area, and slightly pull it out to the side. At the same time we place the implants well be tracking the neuro-vascular bundle. Then the bundle is released and placed back over the implants. The surgical access is refilled with bone graft material of the surgeons choice and the area is closed.
These procedures may be performed separately or together, depending upon the individual's condition. As stated earlier, there are several areas of the body that are suitable for obtaining bone grafts. In the maxillofacial region, bone grafts can be taken from inside the mouth in the area of the chin or lower third molar region or in the upper jaw behind the last tooth. In more extensive situations, a greater quantity of bone can be obtained from the hip. When we use the patients own bone for repairs or additions, we always get the best results.