HISTORY OF BONE GRAFTING
Introduction to Bone Grafting:
When I first came into oral and maxillofacial surgery, we were involved in a great amount of experimentation with many materials for bone grafting. Bone transfer grafts involved the use of ribs, hip bone, tibia and particulate bone grafts. We grafted blocks of ceramic (hydroxylapatite-solid and porous). We tried to get the body to induce bone healing, but only had marginal success. The problem was that our bodies are very good at absorbing bone that they feel does not belong. Also many of the areas we tried to build up have muscle pull and bite pressures that tell the body to absorb the bone.
Infection, contamination (foreign bodies), irritants (chemicals like alcohol, peroxide, menthol, etc), extremes in temperature, and mechanical displacement (to name a few) can also cause the body to reject a graft. We have been generally able to overcome these concerns with proper care and medications.
Past History of Bone Grafting:
Years ago, our initial attempts at bone grafting were largely failures. The area where the most progress was made with these bone grafting trials was in major reconstructions after accidents or cancer. The early researchers in bone grafting, were successful in transferring larger bone grafts using bone cribs (natural bones hollowed out to carry bone graft) and also vascularized grafts (major bone grafts transferred along with tissue and blood vessels to rebuild a jaw). These bone grafting surgeries are fabulous and needed, but are not practical for our day-to-day needs as it relates to the teeth and dental implants.
Synthetics in Bone Grafting:
Bone grafting took a big step with the introduction of synthetics (such as glass ionomers). These materials along with ceramics helped in providing some bridging and we were able to treat quite a few defects with these, but they were not adequate to build bone up. Generally we are able to use them in areas where there is some existing bone to widen or expand, but they do not work well to add bone thickness or adding bone onto a surface of a site.
Your Own Bone:
We have always used native (your own) bone for bone grafting material. Early on we would take bone from the hip or long bones. There were two main problems: the donor site surgery was extensive, and also the native bone is absorbed easily. The body can recognize it and absorb it. We do still use grafts like this in major reconstructions, but it is not practical or necessary for our day-to-day procedures.
Bone Grafting Products:
Human bone products started being introduced in the mid 1990s, but they were hard to get a hold of and these were prohibitively expensive. For us in oral surgery, the use of animal bone product (typically bovine and porcine bone) was introduced and again, expensive at first. The price did come down and it became our mainstay for grafting starting in about 2000. It was helpful with small defects, but it was only marginally helpful in larger grafts such as widening the dental ridge for implants. I used this a lot and some of you have had exceptional grafts with this and I have been successful with building up ridges and placing implants in this material and I say this in humble amazement. I was able to perform the bone grafting procedures, but it is quite a miracle of nature and frankly good genetics in some individuals who accepted this material enough to be successful.
Over a number of years, the human bone product came down in price. It was certainly accepted by the body, but we found that by itself it would tend to absorb. It was still not ideal. BMP (bone morphogenetic protein) is a growth factor or “bone induction factor” our bodies produce which helps to stimulate the body to produce bone. This substance was isolated and we started using it in bone grafts in the 1990s. It was quite expensive when it first came out, but again, as the cost came down, we could use it in our practices. This was a big step in “turning bone on” to produce more bone. Mixed with human bone product, we saw enhanced bone healing. This worked well and again, I have treated a number of you out there with this material and have received successful grafts with this over the past 15 years or so. It was a step better, but still not ideal, especially in that it caused a large tissue response with swelling. It is also still quite expensive.
In the meantime, individuals were experimenting with the use of PRP (platelet rich plasma) which was used in surgical sites along with grafts. This technology made a lot of sense and research seemed to support its use in bone grafting procedures, but we really did not see significant improvement. Some centers really believed in it. I did not find it to give any improved results.
More recently, it was found that blood can be further fractionated (separated) into its parts through centrifugation and pipetting. These are relatively easy techniques that can be done in our office setting and without great cost.
This was the advent of PRGF and this takes us up to our present technology. I have been using the PRGF technology since 2010 and I have used it on hundreds of grafting procedures. We typically use the PRGF along with human bone product as a mixture with great success. I call it a “supercharged bone graft.”
The interesting fact is that it actually works best with the human bone product (cataveric bone) rather than your own bone. When your own bone is used, your body recognizes it as your own and immediately starts to absorb it. The donated bone product is recognized by your body as “normal bone” and so you will grow bone around it. Ultimately, your body absorbs it and lays down your own bone, but it is more difficult for your body to absorb it. It actually takes months to completely absorb and during that extra time, it gives your body the chance to stabilize and mature the bone. It also gives us time to place dental and facial implants or other functional loads on the bone which stimulate it to stay and strengthen.
This is still not a perfect material in that we are still not able to easily graft large areas (areas bigger than your finger). However, that level of bone grafting is enough to be able to build up the ridges for dental implant placement or facial reconstructive surgery (orthognathic surgery).
“Functional load” is a term that is used to describe a functional pressure that is placed on bone that tells it to be maintained. A tooth is an excellent example of a “functional load.” When a healthy tooth is in the jaw bone, it stimulates the bone to be present and strong in order to support the tooth – a functional load. A dental implant, once it is in place and accepted, performs the same stimulation on bone. So when we graft bone to the jaw, after a period of time without a load on it, the body will tend to absorb that bone. There are many factors that contribute, including genetic, functional and environmental.
Key Ingredients to Successful Bone Grafting:
Oxygen is one of the primary or key ingredients to the healing of any type of bone graft. In order to get bone to “take” or heal, your body has to recognize it as “acceptable” (not rejected) and then it needs to initially grow blood vessels into the graft from the surrounding bone and soft tissues. This actually takes place starting almost immediately, but can be accelerated or “induced” by properly preparing the site and with the use of natural graft enhancers such as PRGF.
Next to oxygen, there are “growth factors” which stimulate our bodies to lay down new bone and to grow blood vessels into the graft to nourish it. These growth factors are naturally present in our tissues and given off in areas of injury or where healing is going on, such as a surgical site. But we have discovered that these factors can be isolated and concentrated from our blood. What makes this even crazier is that the very part of the blood that is highest in these factors when the blood is centrifuged also contains the very cells (platelets) which produce the “stem cells” (multipotent fibroblasts) which have the ability to form into any type of tissue that they are “induced” to become. In our case, by mixing them with bone graft and placing them in a bone environment, separating them from the other tissues (barrier graft) – we are able to induce them to become bone development cells (osteoblasts) which will ultimately lay down mature bone in an area where the bone had been missing or deficient. Fantastic!
Maybe that is a little complicated, but suffice it to say: the ease of use of PRGF and human bone product has been a quantum leap for the reconstruction for the dental ridge in order to replace or secure the teeth. We can even use this technology along with block grafts (sections of bone that are taken from your own jaw structure) and build up or widen larger areas.
Soft Tissue Bone Grafting:
Soft tissue bone grafting is another separate subject, but worth mentioning here. When we rebuild up deficient areas of the jaw such as for dental implant treatment, we usually need to improve the tissue bed. Tissue along the dental ridge and along the teeth and implants needs to be thick, strong tissue. We call this tissue “attached gum tissue” and it is the tissue which naturally occurs around the necks of your teeth. It has the characteristic of producing and containing keratin which makes it tough (much the same way the keratin in the skin on the palm of your hand forms a callus). The tissue naturally occurs on the roof of the mouth (palate) and we are able to take tissue from the palate and transplant it to other areas to make them more healthy, such as bone grafted areas of the dental ridge. There are synthetic tissue graft materials which can help in this. The PRGF technology can also be used to enhance this kind of tissue grafting as well.
I am very excited about where our office is at with these procedures. We have stayed at the forefront of bone grafting technology and I continue my education on a regular basis. I look forward to new and even better technologies that will help my patients achieve a high quality of life. These are easy office procedures. If you would like to know how this bone grafting technology can help you, just call (262) 634-4646 and come in for a consult.
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