Bone Augmentation

When teeth are lost the bone surrounding the teeth is removed naturally by the body in a process called resorption. This is a normal process as the bone is only required when there are teeth to support. Resorption takes place very quickly in the first six months and then slows but never stops, the jaws appear over time to shrink, and if left untreated, the loss of bone from the jaw can progress so far that a denture will not stay in place no matter how much denture fixative is used.

As mentioned earlier dental implants have been a great advance in modern dentistry but the modern techniques of bone augmentation are even more impressive. Although we use the term bone augmentation, it is probably more accurate to use two terms, bone grafting and bone growing, though after time, the final results are indistinguishable from each other. True bone grafting is where blocks of bone are harvested and placed in to the deficient jaw, bone growing tends to be where small particles of either bone or synthetic material are held in place and act as a filler into which your body can grow new bone. Both procedures are often used at the same time though bone growing is a much easier procedure.

There are generally four types of materials used for bone augmentation:-

AUTOGRAFTS are those where bone is taken from the donor site in your own body and placed in the recipient site. The donor site is usually either the mouth or the hip. This is your own bone and is very compatible with your body. Autografts are generally the best graft technique and usually result in the greatest regeneration of missing jaw bone but they do require a second surgical procedure to harvest the bone.

ALLOGRAFTS are taken from human donors. Many countries have donor programmes where you can specify in the event of your death, that parts may be harvested from your body to save or improve the life of others. Heart transplants are an obvious example. Bone obtained in this manner undergoes rigorous tests and sterilisation. Your body converts this bone into your natural bone thereby rebuilding the defect.

XENOGRAFTS are harvested from animals. The animal bone, most commonly bovine (cow), is specially processed to make it biocompatible and sterile. It acts like a filler which your body initially uses like a scaffold to build new bone on and then in time converts the xenograft material to your own bone. This is a very easy system to use as the "replacement bone" comes out of a bottle.

ALLOPLASTIC grafts are inert, man made synthetic materials that mimic natural bone. They are usually a form of calcium phosphate and can be either resorbable or non-resorbable. They are again very easy to use as they come in a bottle, and work in very much the same way as Xenografts.