loss (or bone resorption) often occurs when teeth have been
lost but not replaced, with age, or in people who have worn
dentures for some time. When resorption has excessively reduced
the jawbone, dental implants cannot be placed as there is
not enough good-quality bone material for the implant to anchor
to. In these cases, the bone can be rebuilt through modern
bone grafting techniques. Bone grafts can build up or fill
in jawbone defects allowing the successful placement of dental
implants. These techniques represent one of the greatest advances
in modern dentistry.
There are generally four types of bone grafts used:
1. Autografts are those where the bone
to be grafted to the jaw is taken, or harvested, from your
own body. The area where the bone is harvested from, known
as the donor site, is usually 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 jawbone.
2. Allografts are taken from human donors.
Many countries have donor programs where you can specify that
in the event of your death, parts may be harvested from your
body to save or improve the life of others. Heart transplants
are one type of allograft. This can represent one of the greatest
"gifts" you ever give. Bone obtained in this manner
undergoes rigorous tests and sterilization. Your body "converts"
the donor bone into your natural bone, thereby rebuilding
your resorbed jawbone.
3. 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, in time, your body will replace
with natural bone. After this replacement process is complete,
dental implants may be placed to support teeth.
4. Alloplastic grafts are inert, manmade
synthetic materials. The modern artificial joint replacement
procedure uses metal alloplastic grafts. For bone replacement
a manmade material that mimics natural bone is used. Most
often, this is a form of calcium phosphate. Depending on how
it is made, it may be "resorbable" or "non-resorbable".
That is, your body may or may not replace the alloplastic
graft with your natural bone. In those cases where it is not
replaced, it acts as a lattice or scaffold upon which natural
bone is built. In either case, the end result is to create
enough bone for the placement of dental implants.
Modern bone grafting techniques can be nothing short of
a miracle for that needing bone replacement.